Solution Manual For Introduction to Human Factors Applying Psychology to Design 2E y Nancy J. Stone

Solution Manual For Introduction to Human Factors Applying Psychology to Design 2E y Nancy J. Stone Alex Chaparro Joseph R. Keebler Chapter 1-12 Chapter 1 Answers to End of Chapter Exercises 1

Human factors is the application of psychological science. First, identify a psychological phenomenon or finding (e.g., the Zeigarnik effect). Now, give an example of how this information would or would not be considered human factors.

The Zeigarnik effect postulates that we are likely to remember things better when interrupted, but not once a task is completed. For example, wait servers remember orders when they are not complete, but do not recall the orders as well once everyone has been served. This is great when you are constantly getting knew information and can forget the old. This would not work for pilots or drivers who need to remember how to control their respective vehicles.

2

Given the following systems, (1) identify the goals, inputs, process, and outputs, (2) describe how these different parts of the system are interrelated, and (3) describe how the system would be affected if one or more of these parts or functions changed: a. Highway system (1) Goals: to provide safe routes to various destinations. Inputs: drivers, vehicles, weather, infrastructure (to name a few). Process: following proper use of system, making critical decision related to driving (e.g., lane changes). Outputs: safe arrival, accidents (2) Novice drivers, compared to more experienced drivers, are more likely to make slower or incorrect decisions, which could result in not getting to the correct destination (e.g., wrong exit) or having an accident.

(3) As processes improve, there will likely be fewer errors and/or accidents. b. Air transportation system See answers to a as an example. c. Elevator (1) Goals: to raise and lower people and things safely to various levels of a building or structure. Inputs: people, things, buttons/controls (to name a few). Process: know when to enter the elevator, understand how to operate the elevator. Outputs: safe arrival to proper level.

(2) If you replace the adult elevator operator with a child, this will likely impact the processing and inappropriate control of the elevator. \ (3) With a more advanced operator, the elevator controls should be better understood. With better designed controls and signage the operator will make fewer mistakes operating the elevator. d. Bus system See other answers as an example. e. Restrooms (1) Goals: sanitation. Inputs: people, cleaning supplies. Process: hygiene decisions. Outputs: human relief, cleanliness.

(2) If no one is using the restroom, then there is no need to clean or provide cleaning materials, and there would not be any outputs.

(3) If (more) people stopped washing their hands after using the restroom, three would be the spread of more disease. f. Offices

(1) Goals: to meet with people, to process paperwork, etc. Inputs: people, documents, visual cues(to name a few). Process: inviting people in to talk, making decisions on the budget.

Outputs: effective meeting, balanced budget.

(2) Without the proper people in the room, the appropriate documents, etc., it is not possible to have an effective meeting or to make the appropriate budget decision.

(3) With the wrong documentation, there is a greater change of budgetary error. g. Parking lots (1) Goals: to store cars safely. Inputs: drivers, pedestrians, vehicles, signage, traffic rules (to name a few). Process: deciding where to safely park. Outputs: safely parked car.

(2) The input (e.g., pedestrian) will influence how the driver trying to park will or can process the parking rules and not run over the pedestrians.

(3) A novice driver might be less likely to notice the pedestrian or motorcyclist behind the car when backing into a spot.

3

Identify various events that occurred during WWII and explain how they helped the development of the human factors profession.

As one example, you could discuss the problems pilots had in flying airplanes that were built without standardization.

4

If you were having trouble entering phone numbers into your cell phone, explain how a human factors specialist is likely to approach the problem compared to an engineer or an I-O psychologist.

An engineer might focus on the design of the phone and how the phone works (i.e., how the numbers are entered). An I-O psychologist is likely to encourage some form of training. The human factor specialist might be concerned with the size of the buttons for entering the numbers or, due to memory, decay focus on using voice entry instead of manual entry.

5

As a human factors specialist working during WWII, describe the different types of research you would likely conduct and explain how the results could be applied to everyday use.

You might begin by looking at the work by Chapanis and Fitts. The work of experimental psychologists apply here, too. There are many possible answers.

6

What are some of the reasons we need to consider special populations? Give an example of how a lack of consideration of special populations is likely to create errors or decrease safety for the users.

We need to consider special populations so that more users can benefit from the design.

Without considerations for special populations, we might create a cell phone that is too small such that individuals with large fingers will accidentally activate surrounding keys or we create a workspace that has many items locate high overhead whereby individuals who are shorter or have mobility issues could have trouble accessing the materials.

7

Compare and contrast the terms engineering psychology, ergonomics, and human factors.

The three terms all focus on designing for the human user. For some, the term engineering psychology is narrower than human factors, while ergonomics tends to be a term used more commonly in Europe. In addition, ergonomics often focus on the design of furniture and workspaces, but not exclusively.

8

Describe where human factors specialists are likely to work and the types of work they might do.

Human factors specialists could work in a multitude of places such as a computer company designing computer software or games. The HF specialist might work for a nuclear power plant to help design a safer system, or one might work in a hospital developing better protocols to increase patient safety.

9

Consider everyday things you use. Identify what might be considered a human factors problem and describe how you might use human factors to design something that works well.

Mass transit stations (such as the trains in Chicago) have vending machines that have an array of buttons and information that is often incomprehensible if one has not used it before (and sometimes they are not working, which adds to the confusion). A better layout of the instructions by steps using images could help the novice user and those for whom English is not their first language.

10 Human factors is an adaptable field. What makes the human factors specialist capable of applying one’s knowledge and skills to a variety of areas (e.g., law, medicine, travel)?

The key here is that we are looking at designing things for the human users so that the design is understandable, easy to use, and has few errors. All areas tend to have human users of some activity that can be evaluated (e.g., medical tools).

Chapter 2 Answers to End of Chapter Exercises 1

You are studying the impact o f room color on mood. You have college students come into a laboratory where there are two identical rooms, but one room is painted yellow and the other is painted pink. The students perform a vigilance task in either the yellow or pink room. After 30 minu tes, the students’ mood is assessed. a) Describe the population that is being studied.

The population is the adult population; however, depending on the university, it might be skewed toward the younger adult population. b) Describe the sample, how the sample s hould be selected, and the pros and cons of this type of sample. Explain how this sample is different from other types of samples.

The sample is a subset of the adult population and, more specifically, a subset of the student enrolled at the college. Because true random selection is not possible, whereby they should be randomly assigned to the room. c) Describe the groups to which these results could be generalized.

Based on the sample characteristics (e.g., age range 18-24, mean=20, etc.), the results should be generalized to this adult population. d) Write a possible hypothesis for this study.

It is expected that individuals in the yellow room will perform better on the vigilance task that those in the pink room.

2

You are investigating whether individuals truly understand how to use home-use blood pressure monitors. a) Design a research project you could conduct that would have high internal validity.

It would be ideal to work with individuals who must use home-use blood pressure monitors and ask them to participate in your study/experiment. It would be possible to provide real or mock up monitors and ask individuals to perform various functions noting errors and success. b) Explain why this is or is not a quasi -experiment.

This would not be a quasi-experiment, as we are not comparing two groups of individuals (e.g., those using monitors and those who do not use monitors) who were not randomly selected to their groups. Rather, we are comparing different sets of instructions. c) Explain how your sample might influence the results.

Using individuals who actually use monitors will make them more invested and likely give better results than students who are getting credit for an experience. With that said, we could still get a good understanding of differences in instructions or monitor design from students, if that were our sample. d) Discuss what variables might be confounded.

There should not be any confounding in this particular project.

3

For the experiment described in #1, a) What is the independent variable?

Room color. b) What is the dependent variable?

Performance on the vigilance task.

4

Operationalize each of the following: a) Friendliness

The number of times a person smiles in a five minute period. b) “Best” performer On a vigilance task, this could be the person with no or only one error. c) Depressed grandparent.

Someone who makes sad statements ninety-five percent of the time during a 30-minute conversation.

d) Clear and understandable instructions.

Tested to ensure fewer than five percent of the people could not complete the instructions. e) Legible street signs.

Eighty percent or more of the individuals could read the sign. f) Safe environment (e.g., a kitchen or roadway).

The kitchen had no accessible sharp knives. g) Older employees.

Someone over the age of 40 (according to the Age Discrimination in Employment Act).

5

For the following situations, explain how this could be a conflict of interest and how a conflict of interest could be avoided. a) You wish to study the impact of seating design on lower back pain. A large, well-known chair manufacturer is willing to fund your research.

The chair manufacturer has a vested interest, which makes this a COI. To avoid the COI, it would be best to be funded by someone else; however, by reporting the COI and making sure to have a reporting structure in place, it is possible to have the chair manufacturer fund the research.

Check with your organization on process. b) A leading drug manufacturer is willing to fund your research on the development of labels to help reduce the number of misread medicine labels in hospitals.

This is not a COI, as this is not the development of drugs. Rather, this is the development of labels.

6

For the following situations, (1) explain how informed consent would be given, (2) explain whether there is minimal risk or the participants would be at risk, and (3) explain your decision on the risk/benefit ratio (i.e., should the IRB approve this research?).

a) A researcher wants to investigate the validity of a new machine to install in vehicles for identifying if someone is too drunk to drive. The researcher wishes to include in the research individuals who have had at least one DUI (Driving Under the Influence or DWI: Driving While Intoxicated).

(1) The researcher could get informed consent when the individual comes to the lab to test the machine.

(2) Some might consider the knowledge of DUI/DWI to be sensitive, which might increase the risk of the project.

(3) Depending on the means for handling the risk (e.g., anonymity, security), the IRB is likely to approve this project. b) In order to study the impact of ambient noise on hearing perception, the researcher wishes to study the individuals with hearing loss at a nearby nursing home.

(1) Informed consent would be acquired prior to when the research participants begin the research.

(2) As data would be reported in groups (i.e., not identifiable), this seems to be minimal risk, as not being able to hear and ambient noise are similar to everyday events.

(3) The IRB would likely approve this project. c) Faculty members ask their students to participate in a research project in which they will play a videogame. The game has the students “flying a mission” and “eliminating” the enemy. The students will get extra credit if they participate.

(1) The researchers would get informed consent at the beginning of the research.

(2) Playing such a video game is no riskier than many games played by people. This would be considered minimal risk. As with all research, there should options for discontinuing the participation.

(3) The IRB is likely to approve this project.

7

Which type of research, studies or experiments, a) Has greater internal validity? Explain.

Experiments have greater internal validity because there is greater control over the manipulation to truly differentiate the differences. b) Has greater external validity? Explain.

Studies often have more external validity because you are studying individuals in their natural environments; however, with less control over the manipulation.

8

You wish to test the hypothesis that individuals exposed to yellow rooms are happier than individuals exposed to green or blue rooms. a) Design a between-subjects experiment that would test this experiment. That is, identify the independent and dependent variables and explain what the participants would experience. Explain if you would have to use counter-balancing.

Individuals would be randomly assigned to one of the colored rooms (yellow, green, blue) to perform various tasks and then complete a mood survey. There would not be any counterbalancing because the participants only experience one room. b) Design a within-subjects experiment that would test this experiment. Explain if you would have to use counter-balancing.

Individuals would be randomly assigned to a sequence of room experiences (e.g., first blue, then yellow, then green). Participants would perform various tasks and then complete a mood survey.

Some type of counter-balancing should occur (more difficult when three options), but it is possible to determine the possible sequences and then randomize their assignment.

9

For each of the following, (1) explain what the relationship means and (2) explain how the result could be applied. a) The correlation between attendance and performance in an Algebra class is .87.

Those who attend tended to perform better. This could be due to more motivation or more exposure to the material, both, or some unknown variable. b) The correlation between age and cognitive alertness while driving is -.45.

This suggests that older individuals tend to have lower cognitive alertness. It is unlikely that cognitive alertness affects age (i.e., as cognitive alertness increase age decreases)! c) The correlation between room temperature and depression level is .22.

This is a relatively small correlation and might not be applied well.

10 For each of the following, explain how the result could be applied. a) The performance of individuals in the pink room was significantly slower than the performance of individuals in the yellow room.

Yellow might be stimulating or pink depresses activity. If you want to calm people, perhaps using a pink room could help. b) Individuals in the more complex driving simulation had significantly more accidents than individuals in the simpler driving simulation.

Complex driving situations have greater demand and people do not function as well. Having people not talk to the driver during complex driving situations might result in fewer accidents.

11 For the following, (1) determine if the process is ethical and (2) discuss why it is ethical or what you could do to make it ethical, if possible.

a) Some individuals in your vigilance project continue to fall asleep, so you decide to sound an alarm every few minutes to keep them awake.

This is ethical; however, the alarm would need to be a part of the methods or it will be random error. b) Near the end of your data collection you have some students who are frustrated with the project and want to quit. You persuade the students to continue and complete the project.

This is unethical given the use of persuasion. If the researcher asked the participants if they wanted to leave and they decided to stay, that would be fine. c) Your results did not come out as you predicted so you decide to rewrite your hypotheses so that the paper will flow better.

This is HARKing and is unethical. The proper way to handle the results is to report them as they are and discuss reasons for these results. d) Some of your results are as you predicted, but others are difficult to explain. You decide to eliminate the confusing data.

This is not ethical. One should report and discuss the results. The review process helps with the interpretation (i.e., reviewers often give alternative explanations to consider).

12 Given the following frequency distribution table, determine the mean, median and mode.

Response

Frequency

Option 1

1

2

2

3

8

4

6

5

3

Total

20 Mean =3.4 Median = 3 Mode = 3

13 Given the following scatterplots, estimate the correlation coefficient: a) -.85

b) +.60

c)

-.35 Chapter 3 Exercise Solutions 1. Shown in figure 3.8 is a picture of the instrument display from a BMW. Identify the different types of displays (digital, analog, moving indicator fixed scale or fixed indicator moving indicator etc.).

a. Analog: fuel level indicator (1/2), speedometer (50 km), engine temperature (mid level), RPM (1/min x 1000), fuel efficiency display (L/100 km) b. Digital: odometer (61134 km), clock (18:43), radio station setting (104.8) 2. Calculate the visual angle subtended by a four inch tall letter on a sign viewed from 20 ft. Note: that the calculation of visual angle requires that the values of distance and stimulus size be expressed in the same units (ft., inches, mm, etc.). ( (

)

)

3. Calculate the contrast for stimulus with a luminance maximum and minimum of 110 and 100 units, respectively using the three equations shown on page? a. Luminous contrast =

,

b. Contrast ratio =

4. What are some of the principles that guide the location and arrangement of displays? a. There are four principles that guide the location and arrangement of displays in a panel: the importance of use, the frequency of use, the sequence of use, and functional organization.

i. The importance of use and frequency of use principles dictate that regions near the center of the visual field of the operator should be reserved for the most important and frequently used displays. ii. The sequence of use principle specifies that the physical arrangement of displays should match as closely as reasonably possible the order in which they are monitored or used by an operator in the execution of their tasks. iii. The principle of functional organization states that displays illustrating different but functionally related information should be grouped together. The orderly arrangement of displays reduces both eye and head movements and the time to acquire system information.

5. What kinds of tasks are better suited for use of a digital display? a. Digital display are advantageous if an operator has to read exact numerical values but is less advantageous if the numerical values change rapidly.

6. Which wavelengths of light allow an observer to see with the cone photoreceptors while minimizing adaptation of the rod visual system? a. Long wavelength light that would appear red to observers with normal vision. b. Wavelengths greater than approximately 650 nm 7. What percentage of the population has abnormal color vision?

a. About 8% of males and .4% of females 8. Which depth cue would a monocular observer lack? a. Stereoscopic cues 9. What are some of the limitations associated with the use of olfactory displays? a. People quickly become desensitized to odors b. The passive diffusion of odorants limits the ability to direct odors to a particular location or person and the active dispersal of odorants using puffs of air or fans can be distracting and annoying.

Chapter 4 Exercise Solutions 1. What are the perceptual qualities related to the physical properties of sound including intensity and frequency?

Intensity (Amplitude): Perceptual Quality: Loudness Description: Intensity refers to the amplitude or strength of a sound wave, which corresponds to how loud or soft the sound is perceived.

Relationship: As intensity increases, the perceived loudness of the sound also increases.

Conversely, decreasing intensity leads to softer sounds. The perception of loudness follows a nonlinear relationship with intensity, meaning that a doubling of intensity does not necessarily result in a doubling of perceived loudness. Instead, it follows a logarithmic scale.

Frequency (Pitch): Perceptual Quality: Pitch Description: Frequency refers to the rate at which sound waves vibrate, measured in Hertz (Hz).

It determines the perceived pitch of a sound.

Relationship: Higher frequencies are perceived as higher pitches, while lower frequencies are perceived as lower pitches. The human auditory system is sensitive to frequencies ranging from about 20 Hz to 20,000 Hz, although this range varies among individuals. Pitch perception is also influenced by factors such as sound duration, timbre, and context.

Timbre: Perceptual Quality: Tone color or quality Description: Timbre refers to the unique characteristics of a sound that allow us to distinguish between different sound sources, even when they have the same intensity and pitch.

Relationship: Timbre is influenced by various factors, including the harmonic content, envelope (attack, sustain, decay), and spectral characteristics of a sound. For example, a piano and a violin playing the same pitch at the same intensity will have distinct timbres due to differences in their harmonic structure and sound production mechanisms.

These perceptual qualities helps us interpret and make sense of the auditory world around us, allowing us to recognize and differentiate between various sounds based on their intensity, pitch, and timbre.

2. Using equation 1 shown below, calculate the decibel values for each the following examples.

1. P = .0002, Pr = .0002, 0 dB 2. P = .002, Pr = .0002, 20 dB 3. P = .00015, Pr = .0002, -2.5 dB 4. P = .00025, Pr = .0002, 1.9 dB 3. Describe the major structural components of the auditory system associated with the outer, middle and inner ear.

Outer Ear: 

Pinna (Auricle): The visible, external part of the ear that collects sound waves and directs them into the ear canal.



Ear Canal (Auditory Canal): A tube-like structure that leads from the pinna to the eardrum. It funnels sound waves toward the eardrum.

Middle Ear: 

Eardrum (Tympanic Membrane): A thin, cone-shaped membrane that vibrates in response to sound waves. It separates the outer ear from the middle ear and transmits vibrations to the ossicles.



Ossicles (Malleus, Incus, Stapes): Three tiny bones located in the middle ear cavity. The malleus (hammer) is attached to the eardrum and transmits vibrations to the incus (anvil), which then transmits them to the stapes (stirrup). The stapes connects to the oval window of the inner ear.



Eustachian Tube: A narrow tube that connects the middle ear to the back of the nose and throat (nasopharynx). It helps equalize air pressure on both sides of the eardrum, preventing discomfort and maintaining proper function of the middle ear.

Inner Ear: 

Cochlea: A spiral-shaped, fluid-filled structure responsible for converting sound vibrations into electrical signals that can be interpreted by the brain. It contains specialized sensory cells called hair cells.



Vestibular System: Located within the inner ear, the vestibular system consists of the vestibule and semicircular canals. It is responsible for maintaining balance and spatial orientation.



Auditory Nerve: Bundles of nerve fibers that transmit auditory information from the cochlea to the brainstem, where it is further processed and interpreted.



Round Window and Oval Window: Membranes separating the middle ear from the cochlea. The oval window receives vibrations from the stapes and transmits them to the fluid-filled cochlea, while the round window allows for the displacement of cochlear fluid in response to these vibrations.

4. Describe the three sites where the amplitude of sound frequencies is amplified by the ear.

The human ear amplifies sound frequencies at three distinct sites along the auditory pathway: Outer Ear (Pinna and Ear Canal): The outer ear, consisting of the pinna and the ear canal, serves as the entrance to the auditory system. The pinna helps collect sound waves and funnel them into the ear canal.

The ear canal acts as a resonant tube, amplifying sound waves within the frequency range of human hearing, particularly in the range of 2000 to 5000 Hz. This amplification is due to the resonance properties of the ear canal, which enhances sound pressure at certain frequencies.

Middle Ear (Tympanic Membrane and Ossicles): The middle ear is an air-filled cavity located between the eardrum (tympanic membrane) and the inner ear. Sound waves collected by the outer ear cause the tympanic membrane to vibrate. The vibrations of the tympanic membrane are transmitted to three small bones called the ossicles (malleus, incus, and stapes), which form a chain connecting the tympanic membrane to the oval window of the inner ear.

The ossicles acts as a lever system, amplifying the force of the vibrations and thus increasing the pressure of the sound waves before they enter the inner ear. This amplification is crucial for overcoming the inertia of the denser fluid found in the cochlea of the inner ear.

Inner Ear (Cochlea): The cochlea is a spiral-shaped, fluid-filled structure located in the inner ear. Sound vibrations transmitted from the eardrum through the ossicles are focused on the much smaller stapes. The surface area of the eardrum is larger than that of the stapes footplate, the portion of the stapes that contacts the oval window of the Cochlea. When sound waves cause the eardrum to vibrate, the malleus (attached to the eardrum) moves, transmitting these vibrations to the incus and then to the stapes.

Due to the difference in surface area between the eardrum and the stapes footplate, mechanical advantage is achieved. This means that the force exerted by the larger surface area of the eardrum is concentrated onto the smaller surface area of the stapes footplate, resulting in an increase in pressure. This pressure amplifies the sound vibrations before they enter the fluidfilled cochlea of the inner ear.

These three sites of amplification in the ear work together to enhance the perception of sound, ensuring that auditory signals are efficiently transmitted and processed by the auditory system.

5. What are the otolithic organs? What sensory abilities do they support?

The otolithic organs are structures located within the vestibular system of the inner ear, which is responsible for sensing balance, orientation, and spatial awareness. There are two otolithic organs in each inner ear, known as the utricle and the saccule. They are named for the tiny calcium carbonate crystals, called otoliths or otoconia, that are embedded in gelatinous material on their surfaces.

Utricle: The utricle is is positioned horizontally within the inner ear. It contains hair cells that are embedded in a gelatinous substance, with otoliths resting on top of these hair cells. The utricle primarily senses linear acceleration and head tilt in the horizontal plane, such as when moving forward or backward or when tilting the head side to side. It also contributes to the sense of spatial orientation and helps detect changes in velocity during linear motion.

Saccule: The saccule is smaller and more vertically oriented compared to the utricle.

Similar to the utricle, it contains hair cells embedded in a gelatinous substance, with otoliths resting on top. The saccule primarily senses linear acceleration and head tilt in the vertical plane, such as when moving up or down or when nodding the head. It also contributes to the perception of gravity, providing information about the orientation of the head relative to the direction of gravity.

The utricle and saccule, along with the semicircular canals, form the vestibular system, which plays a crucial role in maintaining balance, stabilizing gaze during head movements, and coordinating postural adjustments to prevent falls. The otolithic organs provide essential sensory input that helps the brain understand the body's position and movement in space, allowing for coordinated motor responses and spatial awareness.

6. Which sound frequencies is the auditory system most sensitive to?

The auditory system is most sensitive to sound frequencies within the range of approximately 2000 to 5000 Hz, with peak sensitivity occurring around 3000 to 4000 Hz. This frequency range corresponds to the frequencies of many speech sounds, including consonants like /s/, /sh/, /f/, and /th/, as well as some vowel sounds.

7. Describe the effects of masking on auditory sensitivity?

Masking in auditory perception refers to the phenomenon where the detection or perception of a target sound is affected by the presence of another sound, known as the masker. Masking occurs when the masker makes it difficult for the auditory system to detect or discriminate the target sound, particularly when both sounds share similar frequencies or occur simultaneously. Here are the main effects of masking on auditory sensitivity: Elevated Thresholds: Masking can elevate the threshold of hearing for the target sound, meaning that it becomes more difficult to detect or perceive the target sound in the presence of the masker.

Frequency Selectivity: Masking effects are often frequency-dependent, with the degree of masking being greater when the masker and target sound share similar frequencies. A masker that overlaps with the frequency range of the target sound is more likely to interfere with its perception.

8. How does the effect of masking change as the intensity of the masking tone is increased?

As the intensity of the masking tone is increased, the effect of masking generally becomes more pronounced. This is due to several factors: Increased Masking Level: As the intensity of the masking tone increases, it becomes more effective at masking the target sound. The increased energy of the masking tone makes it more dominant in the auditory system, reducing the detectability of the target sound.

Increased Spread of Masking: With higher intensity masking tones, the spread of masking may extend to neighboring frequency regions.

Overall, increasing the intensity of the masking tone generally leads to more effective masking, reducing the detectability of the target sound.

9. What are the units for subjective loudness, relative loudness and perceived pitch?

Subjective Loudness: The unit for subjective loudness is the sone. The sone is a subjective unit of loudness that quantifies how loud a sound is perceived to be by a listener. It is based on the psychoacoustic perception of loudness and is designed to correlate with the perceived loudness of sounds.

Relative Loudness: The unit of loudness, is the phon, is a subjective unit used to measure the perceived loudness of a sound. The phon scale is designed to correlate with the subjective perception of loudness experienced by an average listener. One phon is defined as the loudness of a 1 kHz tone at a sound pressure level of 1 dB SPL (sound pressure level), which is the threshold of hearing for an average human ear under ideal listening conditions.

Perceived Pitch: The unit for perceived pitch is the mel. The mel is a psychoacoustic unit of pitch that quantifies the perceived pitch of a sound based on human auditory perception. The mel scale is nonlinear and is designed to reflect the perceptual similarity of pitches rather than their physical frequency ratios.

10. What are the auditory cues that listeners use to locate the positions of sounds in the environment?

Listeners use various auditory cues to locate the positions of sounds in the environment. These cues include both monaural cues, which rely on information from one ear, and binaural cues, which involve comparing information from both ears. Here are some of the key auditory cues used for sound localization: Interaural Time Difference (ITD): ITD is a binaural cue that arises from the difference in the time it takes for a sound to reach each ear. Sounds coming from one side of the body reach the closer ear slightly sooner than the farther ear. The brain processes this time delay to determine the direction of the sound source.

Interaural Level Difference (ILD): ILD is a binaural cue that arises from the difference in the intensity of a sound reaching each ear.

When a sound source is off-center, it is louder in the ear closest to it and quieter in the ear farther from it. The brain uses this intensity difference to localize sounds in the horizontal plane.

Shape of Pinna and head: Cues also arise from the filtering effects of the head and outer ears on sounds as they reach each ear. These cues include changes in the frequency content and intensity of sounds depending on their location.

By integrating these various auditory cues, the auditory system can accurately determine the direction and location of sound sources in the environment, enabling spatial awareness and facilitating tasks such as locating objects, navigating environments, and engaging in social interactions.

11. Describe three factors that influence speech intelligibility.

The effects of vocabulary set size, context, and vision on speech intelligibility are significant factors that influence how well speech is understood and comprehended by listeners.

Vocabulary Set Size: The vocabulary set size refers to the number of words used in a speech communication task. Larger vocabulary set sizes typically pose greater challenges for speech intelligibility because they require listeners to recognize and process a wider range of words. As the vocabulary set size increases, listeners may encounter more unfamiliar words, leading to increased cognitive effort in decoding and understanding the speech signal. Conversely, smaller vocabulary set sizes with familiar words and phrases are generally associated with higher speech intelligibility, as listeners can more easily recognize and comprehend the spoken content.

Context: Context refers to the surrounding linguistic, situational, and environmental cues that provide additional information to aid in speech perception and comprehension. Contextual cues can include semantic information, syntactic structure, and situational context. Strong contextual cues can enhance speech intelligibility by providing predictive information about the likely content and meaning of the speech signal. For example, in a conversation about a specific topic, listeners can use contextual knowledge to anticipate the words and phrases that are likely to be used, facilitating faster and more accurate comprehension. However, in contexts with ambiguous or conflicting cues, such as noisy environments or unfamiliar topics, speech intelligibility may be reduced due to difficulties in disambiguating the speech signal.

Vision: Vision, particularly lipreading and facial expression cues, can significantly enhance speech intelligibility, especially in noisy or challenging listening conditions. Visual cues provide supplementary information about the articulatory movements and facial expressions of the speaker, which can aid in speech perception and disambiguation. Lipreading, in particular, allows listeners to extract visual information about the shape and movement of the speaker's lips, helping to distinguish between similar speech sounds and improving overall speech intelligibility. Combining auditory and visual information through audiovisual speech processing can lead to synergistic effects, resulting in greater improvements in speech intelligibility compared to auditory-alone conditions.

Overall, vocabulary set size, context, and vision play important roles in shaping speech intelligibility, with each factor contributing to the listener's ability to decode, understand, and comprehend spoken language in various communication contexts.

12. Why might auditory spatial cues improve the ability of listeners to segregate auditory messages?

Auditory spatial cues can improve the ability of listeners to segregate auditory messages by providing additional information about the spatial location and direction of sound sources in the environment. There are several reasons why auditory spatial cues are beneficial for auditory segregation including the following: Spatial Separation: Auditory spatial cues help to spatially separate sound sources in the environment. When different sound sources originate from different locations in space, listeners can more easily distinguish between them, even if they have similar acoustic properties. Spatial separation reduces the overlap of auditory signals, making it easier for listeners to focus their attention on specific sound sources and segregate them from background noise or competing speech.

Spatial Release from Masking: Auditory spatial cues can enhance the perception of target sounds in the presence of competing noise or masking sounds. When the target and masking sounds are spatially separated the target signal becomes more perceptually distinct from the background noise. This occurs because the auditory system can use spatial information to selectively attend to the target sound while suppressing irrelevant noise sources.

Attentional Focus: Auditory spatial cues help to guide attention towards specific sound sources of interest while ignoring irrelevant or distracting sounds. When listeners can accurately localize sound sources in space, they can direct their attention towards the desired sound source and filter out competing auditory information from other directions.

13. Why might men experience greater hearing loss then women?

Men may experience greater hearing loss than women due to several factors, including biological differences, environmental factors, and lifestyle choices. Here are some reasons why men may be more susceptible to hearing loss: Occupational and Recreational Noise Exposure: Men are more likely to work in noisy environments or industries with high levels of occupational noise exposure, such as construction, manufacturing, and military service. Men may also engage in recreational activities that involve exposure to loud noise, such as hunting, shooting sports, or attending concerts and sporting events without adequate hearing protection.

Healthcare Seeking Behavior: Men may be less likely than women to seek medical attention for hearing problems or to use hearing protection devices. Cultural norms or perceptions of masculinity may discourage men from acknowledging hearing difficulties or seeking help for hearing loss.

Chapter 5 Solutions

5.1

Chapter Exercises – Things to Think about when Answering These

Questions

1. What is user-centered design? Why is it used?

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Involving users in the product design process

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It is used to understand user needs and requirements early in the process

2. What is the difference between an interview and a focus group? What are the types of questions used in each? Give an example of each.

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An interview is typically a one-on-one session with an individual on a topic. Questions may be closed or open-ended and the interview may be structured or unstructured.

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A focus group is a facilitated interview with multiple people at the same time. Questions are typically open-ended and group discussion is encouraged, but in a structured manner.

3. What is the difference between objective and subjective measures? Give an example of each.

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Objective measures are those that do not have the potential for bias. For example, time to complete a task, or number of clicks to complete an online task.

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Subjective measures are ratings or responses that are self-reported by users, such as how easy or difficult a task was to complete.

4. You are exploring the use of cell phones among an older adult population. Design a 5item questionnaire to survey this population on their cell phone usage. Include both closed-ended and open-ended questions.

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There are many options for this questionnaire. A closed-ended question could be “How often do you use your cell phone to text message?” with responses of a) Never b) 1-5 times a day c) 6-10 times a day d) more than 10 times a day. An open-ended question could be “What are the features you like BEST about your cell phone?”

5. You are exploring the use of a new app to capture people's daily exercise and eating habits and display them in a dashboard on their home screen. Assuming your population has never worked with anything like this before, which method of requirements gathering would you recommend? Why? -

Participatory design would help to gather information from different types of individuals.

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Focus groups could help you understand how different groups of individuals think about this information.

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Interviews would be better than a questionnaire because you can follow-up with the individuals in your discussion.

6. You are interested in finding out more about how older adults use the social networking site Instagram. Create a user profile questionnaire for such users. How many target populations do you anticipate finding? Describe the characteristics of each.

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You can define many user groups based on age, technology experience, social media experience, etc. Closed-ended questions should be included to query current usage and experience, along with key demographics. Open-ended questions could be added to query the respondents’ feelings about Instagram. All of this information can be used to characterize the main user profiles.

7. What is card sorting? How is it used to understand users? Describe how you would use a card sort to design the architecture of a website.

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Card sorting is a method to gain an understanding of user conceptual models.

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To design a card sort for a website, you should gather all the key items of information on the site that could be represented in a navigation menu. Then, show the items in a single list (or on physical cards) and ask users to group them in a way that makes sense to them.

Do this with a variety of users. Collectively, this will allow you to see how users of the site think about the information which can be used to create a navigation menu.

8. Conduct a task analysis on making a bologna and cheese sandwich. List all tasks and subtasks necessary to complete this task.

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Starting from the very beginning of gathering the bread, cheese, bologna, etc., map out the exact steps involved in making the sandwich. Test the steps with someone else to see how well it works if they follow the steps exactly.

9. List the tasks and subtasks necessary to extract $500 cash from your local ATM. Identify the potential errors that could occur at each subtask. What improvements, if any, would you recommend to the design of the ATM to reduce the potential for error?

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Each ATM may vary in its design, but in general, start with the initial step of placing the card into the ATM machine and log each subsequent step, along with potential errors (user or system generated) that could occur. Based on this information, suggest ways the system could be improved to minimize error.

10. Suppose you are interested in doing a usability study of your university’s student club website. Define 5 tasks you would have users do to assess its usability. a. How many users would you recruit? What user characteristics would you include in your screening survey? Would you exclude any students from participating? If so, why? b.

What measures would you log for each task and what does each tell you about the site’s usability?

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Tasks may involve first impressions of the club website, find future events, find other members, learn how to join the club, and find contact information for the leader.

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The number of users included should be about 5-10 per user group. You could possibly exclude people already familiar with the site, if the goal is to learn more about the new member experience.

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Measures include task success, task difficulty, errors committed, and overall perceptions of the site usability.

11. Conduct the study you defined in Question 10 with a minimum of 5 participants. a. Create a table of your results. How consistent is the feedback across participants? b. What recommendations do you have to make the site more usable and satisfying to your users? What changes would you make to your study to get more information?

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Tables and charts can be generated to show the results. Identify how the site design could be improved to reduce the chance that errors will occur.

12. Identify a system or product that might present a problem to someone (1) visually challenged, (2) hearing challenged, (3) mobility challenged, and/or (4) cognitively challenged. Describe the potential problems and present possible solutions.

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A mobile phone may be a good example of a product that all of these user groups use. o Visually challenged – are the accessibility options adequate for readability? o Hearing challenged - are the accessibility options adequate for hearing notifications and content on the device? o Mobility challenged – can users hold and manipulate the device to use it in a desired manner? o Cognitively challenged – can the device be simplified in terms of screen design and /or application design?

o Solutions for all of these could be features within the mobile phone system itself or may require additional accessories or software. The key is identifying what, if anything, prevents the user from using the device and determining solutions.

Chapter 6 Exercise Solutions 1. Compare and contrast the properties of the echoic and iconic stores.

Echoic memory and iconic memory are both types of sensory memory that play crucial roles in the initial processing of sensory information. However, they differ in several key aspects: Sensory Modality: Echoic memory pertains specifically to auditory sensory information. It involves the temporary storage and processing of auditory stimuli. Iconic memory, on the other hand, deals with visual sensory information. It involves the temporary storage and processing of visual stimuli.

Duration: Echoic memory typically has a slightly longer duration compared to iconic memory, lasting up to several seconds. This longer duration allows for the processing of auditory information over short time intervals. In contrast, Iconic memory has a very brief duration, usually lasting for only a fraction of a second (less than a second). This rapid decay means that visual information is stored for a very short period, just enough for initial processing.

Capacity: Echoic memory has a moderate capacity, allowing for the retention and processing of several pieces of auditory information simultaneously. Iconic memory also has a moderate capacity, capable of retaining multiple visual stimuli simultaneously. However, its capacity is limited by the brief duration, meaning it can only hold a small amount of visual information at any given moment.

While both echoic and iconic memory are types of sensory memory that temporarily hold and process sensory information, they differ in terms of sensory modality, duration, and capacity.

2. Describe the different types of long-term memories and give examples of each type.

Explicit (Declarative) Memory: Explicit memory involves conscious recollection of information. It is divided into two main subtypes: a. Episodic Memory

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Description: Episodic memory refers to the ability to recall personal experiences and specific events, including the context in which they occurred (time, place, associated emotions).

Example: Remembering your graduation day, including details such as the weather, your feelings, the ceremony, and the people who attended.

b. Semantic Memory  

Description: Semantic memory involves the storage of general world knowledge, facts, concepts, and meanings that are not tied to specific experiences.

Example: Knowing that Paris is the capital of France, understanding the concept of gravity, or recalling that the chemical symbol for water is H2O.

Implicit (Non-Declarative) Memory Implicit memory involves unconscious retention of information and typically influences behavior without conscious awareness. It includes several subtypes (i.e., procedural, priming, classical conditioning, habituation and sensitization) but we focus on procedural memory. a. Procedural Memory  

Description: Procedural memory pertains to skills and tasks that are performed automatically without conscious thought, often acquired through repetition and practice.

Example: Riding a bicycle, typing on a keyboard, or playing a musical instrument.

3. Describe the different strategies you have used to remind yourself to do something in the future (i.e., prospective memory). What kind of cues did you use to remind yourself? Were they time or event based prospective memories? From your experience, were time or event based prospective memories more prone to failure?

Prospective memory involves remembering to perform an intended action or task in the future. Students may report employing various strategies to remind themselves of future tasks, and these strategies often involve using different types of cues. Here are some examples:  Alarms and Timers: Setting alarms or timers on my phone or other devices is one of the most straightforward strategies. These alarms can be time-based, reminding me to do something at a specific time, such as attending a meeting or taking medication.  Calendar Reminders: Utilizing digital calendars and scheduling software allows the user to input future tasks or events with associated reminders. These reminders can be time-based, triggering alerts at designated times before the scheduled task.  To-Do Lists: Maintaining to-do lists is another effective strategy. Users may jot down tasks that need to be completed and review the list regularly to ensure they don't forget any upcoming commitments. To-do lists can include both time-based tasks (e.g., "Complete report by Friday") and event-based tasks (e.g., "Call client after receiving email").

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Visual Cues: Placing visual cues or reminders in prominent locations can be helpful. For example, leaving a sticky note on the refrigerator to remind yourself to buy groceries on the way home serves as an event-based reminder.

Associative Cues: Associating the intended action with a specific event or context can aid in remembering to perform the task. For instance, you could remind yourself to return library books when passing by the library or to send an email when checking my inbox.

Routine Integration: Incorporating the intended action into daily routines can help automate prospective memory. For example, making it a habit to take vitamins with breakfast ensures that you remember to do so each morning.

Regarding whether time-based or event-based prospective memories are more prone to failure, it often depends on individual factors and the nature of the task. Both types of prospective memories can be susceptible to failure under certain circumstances:  Time-Based Prospective Memory: Time-based tasks rely on remembering to perform an action at a specific time. These tasks can be prone to failure if distractions, interruptions, or competing priorities prevent me from noticing or responding to the reminder. Additionally, if the timing of the task is flexible or if you are not in the appropriate context to act on the reminder, you may forget to execute the intended action.  Event-Based Prospective Memory: Event-based tasks are triggered by specific cues or events. While event-based cues can be effective in prompting memory retrieval, they may fail if the cue is not salient enough or if you fail to notice it due to inattention or distraction. Additionally, if the cue is ambiguous or if you encounter similar cues frequently, you may experience retrieval interference, leading to forgetting.

4. Describe Baddeley’s model of working memory. What are the functions of the different components of Baddeley’s model?

Baddeley's model of working memory, proposed by Alan Baddeley and Graham Hitch in 1974, is a theoretical framework that describes the structure and functions of working memory. It consists of multiple components that work together to temporarily store and manipulate information during cognitive tasks. The model includes three main components: Central Executive: The central executive is the control center of working memory, responsible for coordinating and regulating cognitive processes. It allocates attentional resources, plans and executes strategies, and manages the flow of information between different components of working memory and long-term memory. The central executive is flexible and adaptive, allowing individuals to adapt their cognitive strategies to varying task demands and environmental conditions.

Phonological Loop: The phonological loop is responsible for the temporary storage and rehearsal of verbal and auditory information.It consists of two subcomponents: a. Phonological Store: The phonological store holds verbal information in a temporary acoustic or phonological form. It has a limited capacity and duration, typically storing information for a few seconds. b. Articulatory Control Process: The articulatory control process, also known as the inner voice, is responsible for the subvocal rehearsal of verbal information stored in the phonological store. It allows individuals to refresh and maintain phonological representations in working memory through silent speech or inner rehearsal.

Visuospatial Sketchpad: The visuospatial sketchpad is responsible for the temporary storage and manipulation of visual and spatial information. It allows individuals to mentally represent and manipulate visual images, spatial layouts, and spatial relationships. The visuospatial sketchpad is thought to consist of separate visual and spatial subsystems, allowing for the independent processing of visual and spatial information.

Episodic Buffer: The episodic buffer is a temporary storage system that integrates information from multiple sources, including the phonological loop, visuospatial sketchpad, and long-term memory. It provides a limited-capacity workspace where information from different modalities and formats can be combined, manipulated, and temporarily held in a multimodal format. The episodic buffer plays a crucial role in facilitating the integration of information across various cognitive domains and supporting complex cognitive tasks such as reasoning, problem-solving, and comprehension.

5. Explain the difference between bottom-up and top-down influences on the deployment of visual attention.

The deployment of visual attention can be influenced by two main types of processes: bottom-up and top-down. Bottom-up influences are driven by the characteristics of the visual stimuli themselves, independent of the observer's goals or expectations. These influences are often automatic and involuntary, capturing attention based on salient features of the stimuli, such as color, motion, contrast, or sudden changes in the environment.

Top-down influences are driven by the observer's goals, expectations, knowledge, and cognitive processes, shaping how attention is deployed based on internal factors. These influences involve the deliberate allocation of attention to specific aspects of the visual scene that are relevant to the observer's current task, goals, or interests. Top-down processes are sometimes referred to as goal-directed or conceptually-driven attentional mechanisms because attention is guided by the observer's goals and expectations. For example, when searching for a specific object in a cluttered scene, attention is directed to features that are relevant to identifying that object, such as its shape, color, or location, based on the observer's knowledge and expectations.

6. Describe the differences between inattentional blindness and change blindness. Which of these forms of attentional failure may be most closely related to the attentional failure’s drivers’ experience? Explain.

Inattentional blindness and change blindness are both forms of attentional failures, but inattentional blindness occurs when individuals fail to notice an unexpected object or event in their visual field while they are attending to something else. This phenomenon typically occurs when attention is focused on a specific task or stimulus, leading to reduced awareness of peripheral or unexpected stimuli. Inattentional blindness often involves the failure to perceive salient or conspicuous objects or events that would normally be detected under different circumstances. For example, a driver may experience inattentional blindness if they fail to notice a pedestrian crossing the road because their attention is focused on checking their speedometer or adjusting the radio.

Change blindness occurs when individuals fail to detect changes in a visual scene, even when those changes are relatively large or obvious. Unlike inattentional blindness, change

blindness does not necessarily involve the presence of an unexpected object or event. Instead, it involves the failure to detect changes that occur gradually or during a disruption in visual processing (e.g., a saccade or eye movement). Change blindness often occurs when attention is not directly focused on the changing aspects of the visual scene, leading to a failure to encode or detect the changes. For example, a driver may experience change blindness if they fail to notice a road sign that has changed color or position, especially if their attention is focused elsewhere or if the change occurs gradually over time.

Regarding which form of attentional failure may be most closely related to the experience of drivers, both inattentional blindness and change blindness can occur in driving contexts, but they may manifest in different ways. Drivers may be more prone to inattentional blindness when their attention is diverted away from critical aspects of the driving environment due to distractions, cognitive load, or task fixation. For example, drivers who are focused on navigating unfamiliar roads or conversing with passengers may fail to notice unexpected hazards or road signs.

Change blindness may be more relevant to drivers when changes in the visual scene occur gradually or during eye movements (e.g., when scanning the environment). For example, drivers may fail to notice changes in traffic patterns, road conditions, or the behavior of other road users if their attention is not directly focused on monitoring those changes.

7. Experimental evidence suggests that young drivers are more at risk of accidents when talking on a cellular phone. Explain how the theory of automatic versus controlled processing might account for the challenges young drivers face.

Automatic processing refers to cognitive processes that occur effortlessly and involuntarily, often without conscious awareness. These processes are well-learned, highly practiced, and require minimal cognitive resources. For young drivers, basic driving skills such as steering, braking, and maintaining speed may become automatic with practice and experience. These skills are typically performed without conscious effort, allowing drivers to focus their attention on higher-level cognitive tasks such as navigation, hazard detection, and decisionmaking.

Controlled processing, in contrast, involves conscious, effortful cognitive control. It requires the allocation of attention and cognitive resources to actively monitor, regulate, and execute complex tasks. Tasks that involve divided attention, multitasking, or concurrent cognitive demands often require controlled processing. For example, talking on a cellular phone while driving requires drivers to divide their attention between the conversation and the demands of driving.

When young drivers engage in conversation on a cellular phone while driving, they may experience challenges related to the interaction between automatic and controlled processing.

Engaging in a phone conversation requires the allocation of cognitive resources to processing auditory information, formulating responses, and maintaining conversational coherence. This divided attention can compete with the cognitive resources needed for safe driving, particularly for young drivers who may have limited experience and cognitive resources available for driving tasks.

Conversations on a cellular phone can impose a cognitive load that exceeds the capacity of young drivers, leading to cognitive overload and impairments in driving performance. This cognitive load may interfere with the ability to monitor the road environment, anticipate potential hazards, and respond appropriately to changing traffic conditions.

The theory of automatic versus controlled processing suggests that engaging in a phone conversation while driving can challenge young drivers' cognitive resources and attentional control mechanisms, increasing the risk of accidents due to divided attention and cognitive overload. As a result, interventions aimed at reducing distracted driving among young drivers should consider the cognitive demands of concurrent tasks and promote strategies for managing attention and cognitive resources effectively while driving.

Chapter 7 Exercises Solutions 1. Describe the difference between normative and non-normative decision making.

Normative and non-normative decision-making represent two different approaches to understanding and evaluating the rationality and effectiveness of decision-making processes.

Normative Decision-Making: 1. Normative decision-making focuses on identifying and prescribing the "correct" or optimal decision-making process based on rational principles, logical reasoning, and normative standards of rationality.

2. In normative decision-making, decisions are evaluated in terms of their adherence to normative criteria, such as logical consistency, completeness of information, consideration of all available alternatives, and maximization of expected utility or value.

3. Normative models, such as expected utility theory, decision trees, and game theory, provide formal frameworks for analyzing decision problems and determining the optimal course of action based on mathematical principles and probabilistic reasoning.

4. Normative decision-making aims to identify the decision that maximizes expected payoff or utility, given the available information, preferences, and decision criteria.

Non-Normative Decision-Making: 1. Non-normative decision-making refers to decision processes that deviate from normative standards of rationality and optimality, often due to cognitive biases, heuristics, situational constraints, or imperfect information.

2. In non-normative decision-making, decisions may be influenced by psychological factors, emotional responses, social influences, time pressure, or bounded rationality, leading to deviations from idealized rationality.

3. Non-normative decision-making models seek to describe and explain how individuals actually make decisions in practice, taking into account the limitations and biases inherent in human cognition and decision processes.

4. Descriptive models, such as prospect theory, behavioral economics, and dual-process theory, provide insights into the cognitive mechanisms underlying non-normative decision-making, including the role of intuition, emotion, heuristics, and biases in shaping decision outcomes.

Normative decision-making involves prescribing the ideal or optimal decision-making process based on rational principles and normative standards, while non-normative decision-making focuses on describing and explaining how decisions are actually made in practice, considering the influence of cognitive biases, heuristics, and situational factors. Both approaches offer

valuable perspectives for understanding and evaluating decision-making processes, with normative models providing benchmarks for rational decision-making and non-normative models offering insights into the complexities and challenges of real-world decision contexts.

2. Given the method shown for calculating expected value shown on page 7, calculate what the monetary value of winning would need to be such that expected winnings and losses would balance out (i.e., equal 0).

3. Explain the difference between compensatory and non-compensatory methods of evaluating the attributes of decision alternatives.

Compensatory and non-compensatory methods differ in how they combine and weigh the various attributes or criteria when comparing alternative options: Compensatory Methods: a. Compensatory methods involve considering all attributes or criteria of decision alternatives and allowing trade-offs between them. In other words, a decision alternative may compensate for weaknesses in one attribute by offering strengths in another attribute. b. Under compensatory methods, decision-makers assign weights or importance values to each attribute based on their preferences or priorities. Attributes with higher weights contribute more to the overall evaluation of the decision alternative. c. Compensatory methods often involve calculating a total score or utility value for each alternative by aggregating the weighted scores of individual attributes. The alternative with the highest total score is considered the best choice.

Non-Compensatory Methods: a. Non-compensatory methods do not allow trade-offs between attributes; instead, they involve making decisions based on a set of predetermined rules or thresholds for each attribute. In other words, an alternative must meet certain minimum criteria on all attributes to be considered acceptable. b. Under non-compensatory methods, decision-makers apply strict cutoffs or rules to eliminate alternatives that do not meet specified standards on one or more attributes. This approach prioritizes certain attributes or criteria over others and does not allow for compensating strengths in one attribute for weaknesses in another. c. Non-compensatory methods simplify the decision-making process by focusing on essential criteria or deal-breakers, reducing the cognitive burden of evaluating complex trade-offs. However, they may overlook potentially valuable alternatives that excel in some attributes but fall short in others.

2. Describe how expert decision-makers differ from novices. How do experts reduce the effects of work load on decision making?

Expert decision-makers differ from novices in several key ways, including their knowledge, experience, cognitive processes, and decision-making strategies. Below are some of the main differences between expert and novice decision-makers: Knowledge and Expertise: o Experts possess extensive domain-specific knowledge and expertise in their area of specialization, acquired through years of education, training, and practical experience.

They have a deep understanding of the underlying principles, patterns, and nuances of their field, allowing them to recognize and interpret complex patterns and make accurate judgments. o Novices, in contrast, have limited knowledge and experience in the domain and may lack the depth of understanding and expertise exhibited by experts. They may struggle to recognize relevant patterns, make sense of complex information, and apply appropriate strategies in decision-making situations.

Pattern Recognition and Intuition: o Experts excel in pattern recognition and intuitive decision-making, drawing upon their extensive experience and knowledge to quickly identify relevant cues, anticipate outcomes, and make accurate predictions. They rely on mental representations or "mental models" of familiar situations to guide their decision-making process. o Novices, on the other hand, may rely more heavily on analytical reasoning and deliberate problem-solving strategies, as they have not yet developed the intuitive pattern recognition skills characteristic of experts. They may need to expend more cognitive effort and rely on explicit rules or guidelines to make decisions.

Efficient Information Processing: o Experts demonstrate more efficient information processing and cognitive economy in decision-making tasks, filtering out irrelevant information, focusing on critical cues, and allocating attention effectively to important aspects of the problem. They are better able to prioritize and integrate information, leading to more accurate and efficient decision-making outcomes. o Novices may struggle with information overload, processing irrelevant information, or becoming overwhelmed by the complexity of the decision task. They may expend unnecessary cognitive resources on non-essential details or fail to discern the most salient features of the problem.

Decision-Making Strategies: o Experts employ sophisticated decision-making strategies, mental simulation, and recognition-primed decision-making, which leverage their domain-specific knowledge and expertise to guide decision processes. They are adept at adapting strategies to fit the demands of the situation and selecting the most appropriate course of action based on past experience. o Novices may rely on simpler decision-making strategies, such as trial and error, rulebased reasoning, or linear problem-solving approaches, which may be less effective in complex or ambiguous decision contexts. They may benefit from guidance, feedback, and opportunities for experiential learning to develop more sophisticated decision-making skills over time.

In terms of reducing the effects of workload on decision-making, experts employ several strategies to manage cognitive load and maintain performance under pressure: Chunking and Automaticity: o Experts organize information into meaningful chunks or patterns, allowing them to process large amounts of information efficiently and automatically. By automating routine tasks or procedures, experts reduce the cognitive load associated with basic cognitive processing, freeing up cognitive resources for higher-level decision-making.

Selective Attention and Focus: o Experts selectively attend to relevant cues and filter out distractions, enabling them to maintain focus on critical aspects of the decision task. They prioritize information based on its importance and relevance to the decision at hand, minimizing the impact of irrelevant or peripheral stimuli on decision-making performance.

Efficient Decision Strategies: o Experts employ decision strategies that are tailored to the demands of the situation, leveraging their domain-specific knowledge and expertise to guide decision processes. They use heuristics, rules of thumb, and mental shortcuts to simplify complex decision problems and make rapid judgments under time pressure.

Experience-Based Decision-Making: o Experts draw upon their extensive experience and familiarity with similar situations to guide decision-making under workload conditions. They rely on past successes and failures to inform their decisions, using analogical reasoning and recognition-primed decision-making to adaptively respond to novel or uncertain situations.

3. What task characteristics are related to reliable differences between expert and non-experts in decision-making?

Task characteristics play a significant role in distinguishing reliable differences between expert and non-expert decision-making. Below are some task characteristics that are related to reliable differences between experts and non-experts in decision-making: Complexity: o Decision-making tasks that are complex and multifaceted tend to reveal reliable differences between experts and non-experts. Experts excel in navigating complex decision spaces, integrating diverse information, and identifying subtle patterns or relationships that may not be apparent to novices. Non-experts may struggle with the cognitive demands of complex decision tasks, leading to lower-quality decisions or greater reliance on simplistic strategies.

Uncertainty: o Tasks characterized by uncertainty or ambiguity challenge decision-makers to make informed judgments in the absence of complete information. Experts are often more adept at managing uncertainty, drawing upon their domain-specific knowledge, experience, and intuition to make accurate predictions or assessments under uncertain

conditions. Non-experts may exhibit greater hesitancy, indecision, or reliance on random choice in uncertain decision contexts.

Time Pressure: o Time-constrained decision-making tasks place pressure on individuals to make rapid, effective decisions within limited time frames. Experts are typically more efficient and decisive under time pressure, leveraging their experience, intuition, and efficient decision-making strategies to prioritize information and reach timely judgments. Nonexperts may experience greater difficulty in managing time pressure, leading to rushed decisions, errors, or indecision.

Consequences and Stakes: o Decision tasks with high stakes or significant consequences highlight differences between experts and non-experts in their risk perception, tolerance for ambiguity, and willingness to take calculated risks. Experts are often more comfortable with risk and uncertainty, as they have developed robust decision-making strategies and coping mechanisms to manage potential outcomes. Non-experts may exhibit greater aversion to risk, leading to conservative decision-making or avoidance of high-stakes choices.

Feedback Availability: o Tasks that provide immediate or delayed feedback on decision outcomes allow for the evaluation and refinement of decision-making strategies over time. Experts benefit from feedback-rich environments, as they can learn from past experiences, adjust their strategies, and improve decision performance through iterative practice and reflection. Non-experts may struggle to learn from feedback or adapt their decisionmaking approaches, resulting in slower skill development and lower decision quality.

Domain Specificity: o The domain specificity of decision tasks influences the extent to which expertise is transferable across different contexts. Experts demonstrate superior performance in decision tasks within their domain of expertise, where they possess specialized knowledge, skills, and experience. Non-experts may perform comparably to or outperform experts in unfamiliar or unrelated domains where expertise does not confer a significant advantage.

4. What are decision aids and how can they improve human decision-making? Give an example.

Decision aids are tools, techniques, or systems designed to assist individuals in making better decisions by providing structured support, information, guidance, or feedback throughout the decision-making process. These aids can range from simple checklists and decision trees to sophisticated software applications and decision support systems. Decision aids aim to enhance decision-making effectiveness, efficiency, and consistency by facilitating information processing, reducing cognitive biases, and improving the quality of decisions.

5. What is automation bias?

Automation bias refers to the tendency of individuals to rely excessively on automated systems or technology, even when presented with conflicting information or evidence that suggests the automation may be incorrect or unreliable. In other words, automation bias occurs when individuals defer to automated systems' recommendations or outputs without critically evaluating or verifying their accuracy.

Chapter 12 Chapter 12 Alt text Figures Legends Figure 12.1 An adaptation of the SEIPS 2.0 model demonstrating the work system, processes, and patient, provider, and organizational level outcomes (adapted from Holden, Carayon, Gurses, Hoonakker, Hundt, Ozok, & Rivera-Rodriguez, 2013).

Figure 12.2 An example of major teamwork competencies (adapted from Salas, et al., 2014).

Figure 12.3 Team competencies in the TeamSTEPPS framework.

Figure 12.4 Example of an electronic medical record made by EPIC.

Chapter 8 Answers to end of chapter exercises 1. Describe the difference between discrete and continuous controls.

A discrete control is one that can be placed into a finite number of specific states, whereas a continuous control can adopt a continuum, or range, of states.

2. Describe the seven types of control coding described in the text and identify a real-world example of each type.

Controls can be identified and coded by shape, texture, color, size, location, mode of operation, or label. A real-world example of shape coding may be door controls that indicate pushing or pulling by their shape. An example of texture coding may be on a car that has smooth round knobs to operate climate control but fluted round knobs to operate the radio. An example of color

coding may be green and red buttons that turn a machine on or off, respectively. An example of size coding is the power button on a coffee machine being larger than other buttons that change brewing cycle settings. An example of location coding is placing a stovetop knob nearest to the burner that it controls. An example of mode of operation coding may be the use of continuous controls in cars, to operate states of the vehicle that are also continuous in nature – such as a rotating wheel to control steering angle, and foot pedals to control acceleration or braking force.

An example of label coding are symbols placed on a radial knob on a car dashboard that indicate different exterior and/or interior lamp settings.

3. Define elastic and viscous friction and the advantages of using them as a form of resistance in a control.

Elastic friction is a force that resists the displacement of a control and which increases with the magnitude of displacement, and tends to return the control to its original position when the displacement-force is removed. Viscous friction is a force that resists the displacement of a control which remains constant with the magnitude of displacement, and which tends to allow the control to remain in the position it was placed in after the displacement-force is removed.

The use of friction in controls is useful to prevent accidental activation or to provide feedback to the user when the control has been successfully operated.

4. According to research presented in the text, what is the relationship between motor skill and aging, and what affect does experience and expertise have on this relationship?

Motor skill tends to decline in older adults, specifically with regarding to speeded movements, or movements that require muscular strength or two hands working in coordination. However, years of experience performing certain manual tasks may improve performance to such a high level that the age-related declines are counteracted.

5. List and describe three factors that can affect reaction time.

Factors that influence reaction time may include the number of potential stimuli, the number of potential responses, the intensity of the stimulus, and the age of the person.

6. What are the task parameters that make up the Index of Difficulty in Fitts’ law? How do these parameters individually affect movement time?

The two parameters are movement distance and target size/width. Increasing movement distance results in increasing movement time. Decreasing target width results in increasing movement time.

7. Compare and contrast open-loop and closed-loop control.

These are both theories of motor control, but they differ in terms of how and when information is used to plan and organize the movement. In the context of motor performance, closed-loop control involves the continuous/online use of sensory feedback to ensure accuracy in a movement. Open-loop control involves the use of previous motor learning experiences to preprogram an accurate movement.

8. Explain the differences between position, velocity, and acceleration control.

Position control is when a change in position of a controller alters the position of the system (i.e., thing controlled). Velocity control is when a change in the position of the controller alters the velocity of the system. Acceleration control is when a change in the position of the controller alters the acceleration of the system.

9. Define lag and the effect it has on tracking performance.

In systems control, lag is the time delay between when a user’s control input is made to the system and when the change in system state is noticed by the user. Increasing lag can result in inaccuracy and instability/variability in controlling the system state.

10. Compare and contrast pursuit and compensatory tracking displays.

Both are examples of ways to control a system using a controller and a display showing feedback about the system state. A pursuit tracking task occurs when the user operates the control in such a way as to follow, or pursue, a system state that changes dynamically. A compensatory tracking task occurs when the user operates the control so as to maintain a desired fixed system state in the display, and compensates for occasional disturbances to that state.

Chapter 9 Answers to End of Chapter Exercises 1

Using Table 9.1, calculate the 5 th percentile for women’s a. Stature

60 inches (1520 millimeters) b. Leg length This would require the measurement of leg lengths. It would be inappropriate to add the 5th percentile values for, let’s say, buttock-popliteal length and popliteal height together. c. Resting elbow height 7 inches (185 millimeters). This is the distance from seat surface.

2

If your distribution has a mean of 78 and a standard deviation of 8, calculate the 5 th , 50 th , and 95 th percentile point.

64.89, 78, 91.16 3

Determine the ideal desk height and seating height for the 50 th percentile male and the 5 th percentile female when writing at a desk (using Table 9.1).

When writing, the 50th percentile desk height for males: a little above 46 inches (1260 mm).

When writing, the 5th percentile desk height for females: a little above 39 inches (985 mm) 4

Calculate the ideal desk height for writing for the 50 th percentile for all people (i.e., the appropriate surface working height including both men and women).

We need the overall measure, but we can approximate this with the men’s and women’s data: 44.5 inches (1122.5 mm).

5

Observe individuals studying in the library. Identify and describe what needs to be changed for appropriate fit.

The answer will depend on what is being observed.

6

Observe individuals using the computers in the library. Identify and describe what needs to be changed for appropriate fit.

The answer will depend on what is being observed.

7

Evaluate your seating when writing at a desk. Determine if a. Your seating is appropriate. Identify and describe what needs to be changed. b. Your posture is appropriate. Identify and describe what needs to be changed.

The answer will depend on the specific setup.

8

Evaluate your computer workstation and determine what is wrong with the current design. At a minimum, consider seating and surface height, reach envelopes, and line of sight. Identify and describe what you would change to make a better anthropometric fit.

The answer will depend on the specific setup.

9

Evaluate the seating in two different vehicles. Determine if the seating is appropriate for a large number of people (i .e., is it adjustable?). Consider issues of reach and clearance.

The answer will depend on what is being observed.

10 Observe at least one type of check-out counter (e.g., grocery store). Describe what is wrong with this design and what you might change

a. For standing individuals. b. For seated individuals (e.g., people in wheelchairs, seated workers).

The answer will depend on what is being observed.

11 Describe the differences in what you observed and what you would change after evaluating the sitting, reach, and clearance issues at a workstation for a. Children b. The elderly c. Disabled individuals The answer will depend on what is being observed.

Chapter 10 Answers to End of Chapter Exercises 1. You oversee the landscape personnel for the university. They have been w orking in temperatures just above 80º F (26.7º C) with a relative humidity of 45% for the past several weeks. This coming week the temperature is to move into the upper 80’s (31.7º C or higher) with a 70% relative humidity. a. Explain what types of physiological effects are likely to occur.

An individual will likely become flushed and more extreme effects include fatigue, cramps, heat rash, heat exhaustion, or heat stroke. b. What will you recommend that the workers do to avoid negative effects from the temperature?

Drink plenty of water, wear appropriate clothing, and take necessary breaks. c. How might you modify their work schedule, if at all?

Having individuals avoid the hottest part of the day (e.g., work early mornings or later in the afternoon) could help.

2. Road crews are working 24-hour shifts to clear the roads during a strong snowstorm that is likely to last another day or two. The temperature has dropped to below 30º F (-1.1º C) during the day and the wind has increased causing large drifts to clear. a. Explain what types of physiological effects are likely to occur.

The extremities will become cold with the potential for frostbite. With extended time in the cold, someone could experience hypothermia. b. What recommendations will you give your crews to avoid any negative effects due to the cold climate?

Proper clothing is essential to reduce heat loss. Staying dry also is critical. c. How might you modify the work process or schedule to reduce the number of cold-related effects?

Have the workers take warming breaks periodically, especially when the weather is the worst (e.g., windy and wet).

3. For the conditions identified in exercises 1 and 2 above, explain what types of cognitive changes the workers might experience.

Greater cognitive deficits occur when extreme heat or cold. In heat, cognitive deficits occur more so with more complex tasks. Cognitive deficits also seem to be greater with higher amounts of relative humidity.

Some complex tasks impacted in the heat are not necessarily impacted in the cold, but it might impact reasoning, learning, and memory.

4. Explain what the appropriate illumination and set up of the luminaires should be for the following settings. a. Studying in a library, in a dorm room, or outside in a park.

Assuming someone is reading a book, not a computer, then there would need to be higher levels of direct or task lighting. b. Looking for defects in glass bottles.

Having light at an angle to see shadows. c. Preparing dinner (and the users/preparers are of all ages).

Diffuse light to see where things are and not to cut oneself. This would not necessarily need to be high levels, but more lighting might be needed for detail work (dicing). One might need to avoid shadows.

5. Identify various sounds in the following settings that could mask or cause interference with another sound and explain how you could reduce the masking or interference. a. A cockpit or flight deck Different auditory warnings. Would need to make sure that the sounds are distinguishable. b. A car Someone singing in the car and an auditory signal (e.g., the blinker). Having something quite distinguishable to ensure the blinker get turned off when not needed. c. An office People talking and the ring of your office phone. Make sure the ring tone is distinguishable and loud enough. d. A classroom Students talking/whispering when the teacher is talking. Make sure the teacher speaks loud enough (without yelling and becoming hoarse) and stop the classroom talking, if possible.

6. For the sounds identified in exercise 5, explain what the performance effects are likely to be and explain what the likely underlying cause is for this change in performance. a. If the auditory warnings are not heard, proper actions cannot be taken leading to performance deficits. If the warning can be heard, then performance should be appropriate. A louder tone might also increase attention. b. A blinker that is on continuously could cause confusion to the other drivers, leading to potentially dangerous movements (e.g., going around someone signally a right turn).

c. Missing a phone call is not necessarily catastrophic, but if the call is critical, answering it will be important. d. By reducing the interference/masking in the classroom, the students might learn more and be more focused.

7. If individuals working in loud environments (e.g., engine rooms, airport tarmac) wear ear plugs and/or earmuffs, explain how these individuals can best communicate with each other.

Many of the communications could be visual (e.g., signs, facial expressions, lights). Tactile (e.g., touch, vibration of an apparatus) could also convey meaning.

8. Select a space you use frequently (e.g., dorm room, kitchen, office space) and conduct your own link analysis. a. Identify problem areas with the layout.

Answers will depend on the specific location selected. b. Without concern for cost, redesign (but be able to justify) how you would change the layout to make it more efficient.

Answers will depend on the specific location selected. c. Explain what you are satisficing.

Answers will depend on the specific location selected.

9. In designing workspaces, you have the opportunity to select either cellular or open-plan offices. a. Explain under what conditions you would select a cellular or open -plan office.

I would select a cellular office when I need quiet for concentration or I need privacy.

An open-plan office would be great when I am working on something that is not as mentally taxing and I want to interact or communicate with others more freely.

b. If you select an open-plan office, explain whether you would or would not use partitions and what effect this decision might have on performance.

Partitions help reduce visual noise and some auditory noise. If I wanted to have fun and interact with others, I would not use partitions. If I needed some visual privacy, I would select partitions. c. Explain how windows and the office color scheme might impact the workers in this space.

Windows provide stimulation and might provide a means for restoration (e.g., from a cognitively taxing task). Windows might be good for creativity. Various colors also could impact stimulation (e.g., red more stimulation, blue more calming), which might be good when working a boring task (e.g., red) or complex/stimulating task (blue).

10. Explain how you would enhance wayfinding in the fo llowing settings and justify your designs. a. A health care facility for the elderly.

It would be important to make sure the signage was clear/understandable and visible. Graphics or images might help, if understandable. b. An elementary school.

It might be good to paint the rooms different colors and have different colored walls leading to the similarly colored rooms. This way the youngsters could associate a particular hallway with the correct classroom. If it is one hallway, with multiple rooms, then the doorways could be painted the room color. The path to the playground might have an arrow and then a diagram of kids playing. (Definitely have fun with these answers!). c. A shopping mall.

Architecturally, the buildings could be different, which could help. Also, something in the flooring/walkway could assist – arrows with names of stores. Similarly, good signage helps.

Having different textures and/or colors for the pathways could be another means, so people can associate the direction with different textures and/or colors. d. A single-family dwelling with four bedrooms Signage can always be helpful. Using graphics, if someone has dementia, might be an added benefit. Certain types of floors (e.g., hardwood) to designate through path and other types of flooring for the bathrooms, living room, kitchen, etc.

e. A large high-rise apartment or office building.

Good signage and color coding for the floor number would be helpful.

Chapter 11 Answers to End of Chapter Exercises 1. Identify several errors that could occur wh en driving. Explain how these errors could be: a. A slip or a mistake.

Slip: I intended to go to the grocery store after work, but I drove home instead.

Mistake: missing the exit to the airport because the sign was placed after the exit. b. An error of omission or commission (and which types).

Omission: I needed to send a text, but I never hit send.

Commission: I needed to pick up the red pen, but I picked up the blue one. c. A skill-, rule-, or knowledge-based error.

Skill-based error: I have a cup of chai first thing in the morning. This morning, though, I needed to fast for my blood test. Oops.

Rule-based error: the light bulb (lamp) in your hanging light fixture (luminaire) is not working, so you replace it with a new light bulb. Unfortunately, it still does not work (and the bulb wors elsewhere).

Knowledge-based error: Hmm. How to fix this hanging light fixture. After some research on luminaires, you suspect the on/off switch is bad. You buy a new one, install it, and voila, it works!! d. Complete a through c for the following errors. i. Missing a deadline.

This is a slip if I got distracted or forgot the deadline. It could be a mistake if the information shared with me about the deadline was wrong. It could possible be rule-based error, if assignments were normally submitted on Thursdays and this was due on Tuesday. ii. Going to the wrong building for your meeting.

This could be skill-based error (habit) when they changed the meeting location. iii. Sending the e-mail to the wrong person(s).

This could be an error of commission.

2. Compare and contrast the different ways to categorize errors. a. Explain how slips and mistakes are similar to or different from errors of omission and commission.

Slips and mistakes are both output errors, which means the wrong thing was executed. These would be errors of commission. The one exception would be when a slip occurs because it is normal to do nothing, but some action was needed. This would be an error of omission. b. Explain how slips and mistakes are similar to or differe nt from skill-, rule-, and knowledge-based errors.

Skill-based errors are slips/lapses. Mistakes are incorrect planned behaviors, which would include rule- and knowledge-based errors. c. Explain how errors of omission and commission are similar to and different from skill-, rule-, and knowledge-based errors.

Errors of omission and commission could align with any of the SRK-based errors. For example, if the automated behavior is to not do anything, but something is needed, that is skill-based.

When the skill-based action is wrong for that moment, that becomes an error of commission. If the person performs an action (rule- or knowledge-based) and it is incorrect, this would be an error of commissions.

3. Explain how each classification system helps you underst and the underlying problem.

The different classification systems help us understand the errors in terms of input, process, and output.

4. Norman talked about knowledge “in the head” and “in the world.” Design a process or tool two ways, one way for each of these two different types of knowledge. Explain how these processes or tools work differently because of the focus on the different types of knowledge required.

If I designed a computer system to process reimbursements, it would be “in the head” if each step of the process was ambiguous and required extensive training to use. An “in the world” system would open with “Step 1: Upload receipt” with a space for doing so. Then it would have, “Step 2: Provide explanation for reimbursement” with a text box. This would continue until all

NECESSARY information was collected. At the bottom, it would state, “Click SUBMIT to submit your reimbursement request.”

5. Write out in detail how you would perform the steps of a human reliability analysis for the following situations. You will need to create the situation and estimate probabilities. a. A car accident.

See the steps in Table 11.2 to guide the selection of action. You might have: Unlock car  get into car  buckle up  start car back out of parking spot  pull into traffic  observe traffic signs and lights  navigate to destination.

Next determine performance criteria (which will depend on the list of tasks above), identify where errors could occur and their respective probabilities (will depend on what values were estimated). b. Withdrawing the incorrect amount of cash from an ATM. Follow the steps in Table 11.2. For example, pulls up to ATM machine  enters card  enters passcode  enters desired activity  enters dollar amount or selects predetermined amount  retrieves cash. Determine performance criteria, areas where errors could occur, and estimate probabilities. c. Completing a semester-long group project for class.

This answer will follow the same process, but will depend on the setup of the project.

6. Explain whether the following is an accident. a. A chemical spill.

This is an accident only if there is some damage or injury. b. Someone loses control of the car and drives over a curb.

If there was damage or injury, it would be an accident. c. The garbage disposal is turned on when a utensil is in it.

There is damage, which would be an accident.

7. Consider the following situations. Identify potential individual and system factors contributing to errors.

a. A driver falls asleep behind the wheel.

This is mainly an individual factor whereby the individual is not getting enough sleep. It could be a system factor if a business is not allowing individuals to have time for rest. Airlines have mandatory time limits whereby pilots will often “time out” and you will need another pilot before your plane can depart. b. A parent forgets to pick up the children after school (yes, this happens!).

Most likely an individual factor, which could be related to stress. As a potential system factor, it could be bad planning on the part of the parent. c. Submitted reports are late.

This could be an individual issue, but poor communication from the system could lead to a misunderstanding of when reports are do or the system used for submitting the reports are not apply “in the world” designs. d. Reports are completed incorrectly.

At the system level, this could be due to the design of the forms whereby it is not clear what is desired. At the individual level, it could be due to someone’s lack of conscientiousness.

8. Explain how you might reduce errors by addressing the individual and system factors identified in #7 above. a. Get the person on a good sleep cycle. As with medical residents, restrict work hours. b. Come up with a checklist to make sure various steps, such as picking up child, is not skipped. c. Provide a checklist or work aid. d. Redesign the form for clarity.

9. Design warnings. a. Identify and describe an example of a bad warning i. Explain how you would make this an effective warning.

This would depend on the example provided. ii. Justify why this modification is good.

This would depend on the example provided. b. Identify and describe a situation that needs a warning. Create a warning to meet this need.

This would depend on the example provided.

10. Explain how you would test (i.e., research) a. The effectiveness of a warning.

One way would be to implement warnings and then track the number of errors. Before implementing the warnings, one could test whether the warning is noticeable, understood, and implementable (the instructions of the warning). b. The cause of an error.

As an example, if the error is turning right on a red light when it is not safe, one could create different scenarios in a driving simulator to see when people were most likely to turn right (when it was unsafe). c. The best way to reduce error.

Warnings are not the first choice, but should be part of the solution. The first thing to do is to eliminate/reduce the cause of the error as much as possible. This is a problem at the system level.

Once the system (whether that is a better designed saw or more training), Chapter 12 Exercise Solutions Practicing your literature review skills – Conduct a medical HF literature review a. Preparation – Students will need access to a computer and hopefully a school library although scholar.google.com can suffice. b. Students should decide on a topic of interest in the area of HF/E in medicine and find 10 relevant articles from no later than 10 years ago c. Students should read each article and create a code sheet using excel or a similar program. The spreadsheet should contain the following columns: 1. The article’s title and authors, 2 The article’s overarching purpose 3. Whether it’s a theoretical, review, or empirical paper, 4. What the major contributions of the paper are to the field, and 5. A summary of next steps for research given the articles findings? d. The students should create 2 reference lists – one in APA format and one in AMA format. APA rules can be found here: http://www.easybib.com/guides/students/writing-guide/iv-write/a-formatting/apapaper-formatting/AMA rules can be found here: https://www.lib.jmu.edu/citation/amaguide.pdf

2. Teamwork in Medicine - Two teamwork models are provided in Chapter 12.

Noticeably, they both have only a few constructs/factors that they focus on.

Teamwork is much more complex than the models presented, yet both of these models are important and adopted in the field. Why do you think these models are simplistic? What are positive and negative ramifications of this simplification? What could be done to capture more information in the model without making it overcomplex in regards to medical practice?

3. Thinking about standardization - usability versus flexibility - Medical professionals are inundated with rules, regulations, and mandates from all levels of their organization, their professional societies, and the government. We know from the chapter on usability that most tools have a usability flexibility trade off. In general, the more flexible a tool is the less usable it is and vice versa. In recent years there has been a mandate for medical professionals to use standardized tools when handing patient’s over during care transitions (i.e. passing one patient to another provider or unit for the next step in their care). This is often accompanied by a set of checklists or protocols that help guide providers in their information exchange. What kind of issues could tools like this face when being implemented? What role does technology play, if any, in this sharing of information? It is speculated that approximately 70% of adverse medical events occur due to ―failures in communication‖ – how can we address this problem using HF/E methods?

4. The problem with medical errors – Preparation – The instructor should provide the following two articles to students if available, and their abstracts if not. a. Makary, M. A., & Daniel, M. (2016). Medical error—the third leading cause of death in the US. Bmj, 353, i2139. b. Stokowski, L. A. (2016). Who believes that medical error is the third leading cause of hospital deaths. Medscape, May, 26.

Medical errors appear to be a huge problem in modern day medicine, but their measurement and evaluation is still not standardized and validated. Have students read Makary’s and Stowkowski’s papers and compare and contrast the two articles in regards to medical error rates. Which article seems to be more accurate? Is there any bias in either article that could be affecting their findings? Is there a way to synthesize the two disparate views into a more comprehensive understanding of the medical error space?

5. Error thought problem - Discuss the philosophy of an error - when does an error actually become an error? Often times we estimate an error’s presence by the outcomes we see - accidents, injuries, and deaths. But can errors exist without a negative outcome? Can negative outcomes exist without errors? How does a ―systems approach‖ affect the way we look at errors and react to them?

6. Provide four examples of automated system that you interact with during your daily activities.

Examples of automated systems include the following: Smartphone Assistants (e.g., Siri, Google Assistant): These AI-powered assistants respond to voice commands to perform various tasks such as setting reminders, sending messages, making calls, or searching the web.

ATMs (Automated Teller Machines): ATMs allow users to perform banking transactions such as withdrawing cash, depositing checks, transferring money between accounts, and checking account balances without the need for human tellers.

Smart Home Devices (e.g., Smart Thermostats, Smart Lights): These devices can be controlled remotely or automatically adjust settings based on user preferences or environmental conditions. For example, smart thermostats regulate home temperature, while smart lights can be programmed to turn on or off at specific times.

Online Shopping Platforms (e.g., Amazon, eBay): E-commerce websites utilize automated systems for various tasks such as recommending products based on past purchases, processing payments securely, managing inventory, and tracking shipments.

7. Using Table 12.1as an example identify the levels of automation employed by the following systems: vehicle cruise control, thermostats, microwave, Zumba?

Vehicle cruise control Thermostats Microwave Roomba

Level 2 Level 1 Level 1 Level 2

8. List the pros and cons of requiring human operators to monitor an automated system. Considering your list of pros and cons, what recommendation would you make regarding the role of a human operator in supervising the activity of an automated system?

Pros: Error Detection and Correction: Human operators can quickly identify errors or anomalies that the automated system might miss and take corrective action.

Adaptability: Humans can respond to unexpected situations that the automated system may not be programmed to handle, providing flexibility and adaptability.

Complex Decision Making: In situations requiring nuanced judgment or ethical considerations, human operators can make decisions that take into account broader context and implications.

Cons: Cost: Employing human operators can be costly compared to relying solely on automated systems, especially in the long term.

Response Time: Human reaction times may be slower than automated systems, leading to delays in addressing issues or emergencies.

Human Error: Just like automated systems, human operators can make mistakes, potentially introducing errors into the system.

Dependency: Relying too heavily on human operators may diminish trust in the automated system and undermine its effectiveness.

9. Describe the types of interfaces you use during your daily activities (i.e., physical keyboards, voice etc). Are there particular applications that are better suited for

certain modes of interaction (i.e., touch, voice, gesture recognition, etc?). What are some of the challenges or problems you have experienced using each of these types of interfaces?

In their daily activities, students may interact with various types of interfaces, each serving different purposes and offering unique advantages and challenges: Physical Keyboards and Mice: These are commonly used for inputting text and navigating graphical user interfaces on computers. Physical keyboards offer tactile feedback, allowing for precise typing, while mice provide accurate pointing and clicking. Challenges include repetitive strain injuries from prolonged use and limited mobility for individuals with disabilities.

Touchscreens: Touchscreens are prevalent in smartphones, tablets, and many other electronic devices. They offer intuitive interaction through gestures like tapping, swiping, and pinching.

Touchscreens are well-suited for tasks that involve direct manipulation of objects or content, such as browsing the web or playing games. However, challenges include accidental touches, smudging, and difficulties for users with limited dexterity or visual impairments.

Voice Interfaces: Voice interfaces, such as virtual assistants like Siri or Google Assistant, enable hands-free interaction by recognizing and responding to spoken commands. They are particularly useful for tasks like setting reminders, making calls, or controlling smart home devices while multitasking or when hands are occupied. Challenges include inaccuracies in speech recognition, especially in noisy environments, and privacy concerns related to voice data collection.

Gesture Recognition: Gesture recognition systems detect and interpret movements of the body or hands to control devices or interact with virtual environments. Examples include motionsensing gaming consoles like the Kinect or hand gestures for navigation in augmented reality applications. Gesture interfaces can provide immersive and intuitive interactions, but challenges include limited accuracy, fatigue from prolonged gesturing, and the need for clear line-of-sight between the user and the sensor.

Certain applications are better suited for specific modes of interaction:  Tasks requiring precise text input or data manipulation are often best suited for physical keyboards and mice.  Activities involving direct manipulation of on-screen elements, such as drawing or resizing, are well-suited for touchscreens.  Hands-free operation or tasks performed while multitasking may benefit from voice interfaces.  Immersive experiences or virtual environments may leverage gesture recognition for intuitive interaction.

10. Describe one application where BCI’s may be of use to the broader population users either in the workplace or at home.

A promising application of Brain-Computer Interfaces (BCIs) that could benefit a broad population of users, both in the workplace and at home, is in the field of assistive technology for individuals with physical disabilities. Specifically, BCIs could be utilized to control assistive devices, such as prosthetic limbs, wheelchairs, or communication devices, using brain signals. Below are several examples of uses at home and in the workplace.

Individuals with spinal cord injuries or amputations often face challenges in controlling their prosthetic limbs or mobility aids effectively. Traditional interfaces like joysticks or switches may not provide precise or intuitive control, limiting the user's independence and quality of life. BCIs offer a potential solution by enabling direct communication between the user's brain and the assistive device.

In the workplace, individuals with disabilities could use BCIs to operate computers, control machinery, or navigate workspaces more efficiently. BCIs could empower them to perform tasks that were previously challenging or impossible due to their physical limitations, thereby enhancing their productivity and employment opportunities.

At home, BCIs could facilitate greater independence and autonomy for individuals with disabilities in activities of daily living, such as cooking, cleaning, or accessing electronic devices. By controlling household appliances or smart home systems through brain signals, users could perform tasks with greater ease and efficiency, improving their overall quality of life.