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Indeed, behavioral science is a living discipline. While many of the effects in this book have been replicated across studies, cultures, and time, some may not stand the test of further scrutiny. We include replicability notes in each chapter to highlight the current state of evidence, and we will endeavour to dynamically update these sections as new data emerge. Finally, if you find yourself puzzled, challenged, or inspired by the biases in this book—or if you spot an error, a mischaracterisation, or a blind spot—we warmly invite you to reach out via our website https://bigbadbiasbook.com. The journey to better understand human thinking is not one any of us can complete alone. This book is meant to spark curiosity, provoke thought, and perhaps even foster a little self-compassion. We hope you enjoy exploring it as much as we enjoyed creating it. Ganna and Karen Sydney and Glasgow, 2025

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Table of Contents About the Authors ................................................................................................................................................ v Preface ............................................................................................................................................................... vii Introduction: How To Read This Book .................................................................................................................. 1 Section I INDIVIDUAL ............................................................................................................................................ 7 Part 1 Personal Characteristics ............................................................................................................................. 9 Being Human Is Not Irrational ............................................................................................................................ 11 Ambiguity attitude ............................................................................................................................................. 12 Risk attitude ....................................................................................................................................................... 14 Part 2 “Limitations” of the Brain ........................................................................................................................ 17 Mind Is Flat ......................................................................................................................................................... 19 Availability heuristic ........................................................................................................................................... 20 Bizarreness effect ............................................................................................................................................... 22 Consistency bias ................................................................................................................................................. 24 Context effect ..................................................................................................................................................... 26 Conservatism or Regressive bias ........................................................................................................................ 28 Cross-race effect ................................................................................................................................................ 30 Cryptomnesia ..................................................................................................................................................... 32 Egocentric bias ................................................................................................................................................... 34 Fading affect bias ............................................................................................................................................... 36 False memory ..................................................................................................................................................... 38 Generation/Self-generation effect ..................................................................................................................... 40 Google effect ...................................................................................................................................................... 42 Humor effect ...................................................................................................................................................... 44 Lag effect ............................................................................................................................................................ 46 List-length effect ................................................................................................................................................ 48 ix

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Levels-of-processing effect ................................................................................................................................ 50 Leveling and sharpening .................................................................................................................................... 52 Mood-congruent memory bias .......................................................................................................................... 54 Misinformation effect ........................................................................................................................................ 56 Modality effect ................................................................................................................................................... 58 Next-in-line effect .............................................................................................................................................. 60 Part-list cueing effect ......................................................................................................................................... 62 Primacy, recency & serial position effect ........................................................................................................... 64 Positivity effect (Socio-emotional selectivity) .................................................................................................... 66 Peak-end rule ..................................................................................................................................................... 68 Picture superiority effect ................................................................................................................................... 70 Choice-supportive bias ....................................................................................................................................... 72 Contrast effect ................................................................................................................................................... 74 Declinism ............................................................................................................................................................ 76 Implicit association ............................................................................................................................................ 78 Negativity bias or Negativity effect .................................................................................................................... 80 Processing difficulty effect ................................................................................................................................. 82 Source confusion ................................................................................................................................................ 84 Suffix effect ........................................................................................................................................................ 86 Spotlight effect ................................................................................................................................................... 88 Spacing effect ..................................................................................................................................................... 90 Self-relevance effect .......................................................................................................................................... 92 Suggestibility ...................................................................................................................................................... 94 Stereotypical bias ............................................................................................................................................... 96 Testing effect ..................................................................................................................................................... 98 Telescoping effect ............................................................................................................................................ 100 Tachypsychia .................................................................................................................................................... 102 Travis syndrome ............................................................................................................................................... 104 Tip of the tongue.............................................................................................................................................. 106 Reminiscence bump ......................................................................................................................................... 108 von Restorff effect 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Verbatim effect ................................................................................................................................................ 112 Zeigarnik effect................................................................................................................................................. 114 Anchoring or focalism ...................................................................................................................................... 116 Attentional bias ................................................................................................................................................ 118 Focusing effect ................................................................................................................................................. 120 Frequency illusion or Baader-Meinhof effect................................................................................................... 122 Selection bias ................................................................................................................................................... 124 Part 3 Judgement ............................................................................................................................................. 127 Everything is relativE ........................................................................................................................................ 129 Duration neglect ............................................................................................................................................... 130 Gambler’s fallacy .............................................................................................................................................. 132 Hyperbolic discounting ..................................................................................................................................... 134 Licencing effect ................................................................................................................................................ 136 Moral credential effect..................................................................................................................................... 138 Recency illusion ................................................................................................................................................ 140 Projection bias .................................................................................................................................................. 142 Present bias ...................................................................................................................................................... 144 Time-saving bias ............................................................................................................................................... 146 Attribute substitution ....................................................................................................................................... 148 Automation bias ............................................................................................................................................... 150 Berkson’s paradox ............................................................................................................................................ 152 Base rate fallacy or Base rate neglect .............................................................................................................. 154 Clustering illusion ............................................................................................................................................. 156 Conjunction fallacy ........................................................................................................................................... 158 Distinction bias ................................................................................................................................................. 160 Default effect ................................................................................................................................................... 162 Decoy effect ..................................................................................................................................................... 164 Framing effect .................................................................................................................................................. 166 Information bias ............................................................................................................................................... 168 Less-is-better effect.......................................................................................................................................... 170 Neglect of 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Parkinson’s law of triviality .............................................................................................................................. 174 Regressive bias ................................................................................................................................................. 176 Survivorship bias .............................................................................................................................................. 178 Subadditivity effect .......................................................................................................................................... 180 Well travelled road effect ................................................................................................................................ 182 Zero-sum bias ................................................................................................................................................... 184 Dunning-Kruger effect...................................................................................................................................... 186 Hard-easy effect ............................................................................................................................................... 188 Overconfidence effect...................................................................................................................................... 190 Pessimism bias ................................................................................................................................................. 192 Restraint bias ................................................................................................................................................... 194 Congruence bias ............................................................................................................................................... 196 Insensitivity to sample size .............................................................................................................................. 198 Illicit transference ............................................................................................................................................ 200 Law of the instrument ...................................................................................................................................... 202 Look-elsewhere effect...................................................................................................................................... 204 Observer-expectancy effect ............................................................................................................................. 206 Outcome bias ................................................................................................................................................... 208 Planning fallacy ................................................................................................................................................ 210 Surrogation ...................................................................................................................................................... 212 Weber-Fechner law .......................................................................................................................................... 214 Denomination effect ........................................................................................................................................ 216 Disposition effect ............................................................................................................................................. 218 Endowment effect ........................................................................................................................................... 220 IKEA effect ........................................................................................................................................................ 222 Irrational escalation/Escalation of commitment ............................................................................................. 224 Loss aversion .................................................................................................................................................... 226 Money illusion .................................................................................................................................................. 228 Not invented here ............................................................................................................................................ 230 Pseudocertainty effect ..................................................................................................................................... 232 Unit bias 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Part 4 Decision Making ..................................................................................................................................... 237 Belief is reality .................................................................................................................................................. 239 Backfire effect .................................................................................................................................................. 240 Belief bias ......................................................................................................................................................... 242 Confirmation bias ............................................................................................................................................. 244 Continued influence effect ............................................................................................................................... 246 Conservatism (belief revision) .......................................................................................................................... 248 Experimenter’s or expectation bias ................................................................................................................. 250 End-of-history illusion ...................................................................................................................................... 252 Exaggerated expectation .................................................................................................................................. 254 Forer effect or Barnum effect .......................................................................................................................... 256 Form function attribution bias ......................................................................................................................... 258 Hindsight bias ................................................................................................................................................... 260 Hot-hand fallacy ............................................................................................................................................... 262 Illusion of control ............................................................................................................................................. 264 Illusory correlation ........................................................................................................................................... 266 Illusion of validity ............................................................................................................................................. 268 Illusory truth effect .......................................................................................................................................... 270 Mere exposure effect ....................................................................................................................................... 272 Normalcy bias ................................................................................................................................................... 274 Omission bias ................................................................................................................................................... 276 Ostrich effect .................................................................................................................................................... 278 Pareidolia ......................................................................................................................................................... 280 Reactive devaluation ........................................................................................................................................ 282 Risk compensation/Peltzman effect................................................................................................................. 284 Rhyme as reason effect .................................................................................................................................... 286 Subjective validation ........................................................................................................................................ 288 Semmelweis reflex ........................................................................................................................................... 290 Selective perception ......................................................................................................................................... 292 Status quo bias ................................................................................................................................................. 294 Zero-risk bias 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Inferences are key ............................................................................................................................................ 299 Ambiguity effect ............................................................................................................................................... 300 Allais paradox: Common consequence effect .................................................................................................. 302 Allais paradox: Common ratio effect ............................................................................................................... 304 Ellsberg paradox ............................................................................................................................................... 306 St Petersburg paradox...................................................................................................................................... 308 Violation of transitivity..................................................................................................................................... 310 Violation of independence ............................................................................................................................... 312 Violation of dominance .................................................................................................................................... 314 Anthropocentric thinking ................................................................................................................................. 316 Anthropomorphism or personification ............................................................................................................ 318 Functional fixedness ........................................................................................................................................ 320 Dread aversion ................................................................................................................................................. 322 Empathy gap .................................................................................................................................................... 324 Impact bias ....................................................................................................................................................... 326 Interoceptive bias ............................................................................................................................................ 328 Optimism bias .................................................................................................................................................. 330 Pro-innovation bias .......................................................................................................................................... 332 Reactance ......................................................................................................................................................... 334 Salience bias ..................................................................................................................................................... 336 Section II SOCIAL .............................................................................................................................................. 339 Part 5 Social...................................................................................................................................................... 341 Interaction effects ............................................................................................................................................ 343 Authority bias ................................................................................................................................................... 344 Actor-observer bias .......................................................................................................................................... 346 Cheerleader effect ........................................................................................................................................... 348 Defensive attribution hypothesis ..................................................................................................................... 350 Egocentric bias ................................................................................................................................................. 352 Extrinsic incentives bias ................................................................................................................................... 354 False consensus effect ..................................................................................................................................... 356 Fundamental attribution 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False uniqueness bias ....................................................................................................................................... 360 Halo effect ........................................................................................................................................................ 362 Illusion of asymmetric insight .......................................................................................................................... 364 Illusion of transparency .................................................................................................................................... 366 Illusory superiority ........................................................................................................................................... 368 Illusion of external agency ............................................................................................................................... 370 Just-world hypothesis ...................................................................................................................................... 372 Moral luck......................................................................................................................................................... 374 Naïve cynicism .................................................................................................................................................. 376 Naïve realism .................................................................................................................................................... 378 Ben Franklin effect ........................................................................................................................................... 380 Bias blind spot .................................................................................................................................................. 382 Compassion fade .............................................................................................................................................. 384 Curse of knowledge .......................................................................................................................................... 386 Courtesy bias .................................................................................................................................................... 388 Hostile attribution bias ..................................................................................................................................... 390 Identifiable victim effect .................................................................................................................................. 392 Pygmalion effect............................................................................................................................................... 394 Social desirability bias ...................................................................................................................................... 396 Shared information bias ................................................................................................................................... 398 Singularity effect .............................................................................................................................................. 400 System justification .......................................................................................................................................... 402 Self-serving bias................................................................................................................................................ 404 Sexual over/underperception bias ................................................................................................................... 406 Trait ascription bias .......................................................................................................................................... 408 Ultimate attribution error ................................................................................................................................ 410 Worse-than-average effect .............................................................................................................................. 412 Collective effects .............................................................................................................................................. 415 Availability cascade .......................................................................................................................................... 416 Bandwagon effect ............................................................................................................................................ 418 Group attribution error 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Groupthink ....................................................................................................................................................... 422 Herding............................................................................................................................................................. 424 Ingroup bias ..................................................................................................................................................... 426 Outgroup homogeneity bias ............................................................................................................................ 428 Social comparison bias ..................................................................................................................................... 430 Stereotyping ..................................................................................................................................................... 432 Third-person effect .......................................................................................................................................... 434 Women are wonderful effect........................................................................................................................... 436 INDEX ............................................................................................................................................................... 438

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INTRODUCTION: HOW TO READ THIS BOOK Ever flipped through a medical encyclopedia and suddenly convinced yourself you had every illness listed? Reading this book might feel a bit like that—only the diagnoses are cognitive biases. That’s not necessarily a bad thing. It turns out that recognising biases—especially your own—is the first step toward understanding how the mind really works. Yet, this book isn’t designed to diagnose, but it will certainly provoke reflection. Some entries may feel uncomfortably familiar. Others might explain behaviors you have witnessed in conversations with others, meetings, relationships, politics, or markets. And some will simply make you laugh, because they are so absurd—and so recognisable. What This Book Is—and What It Is Not The Big Bad Bias Book is not a manifesto, nor a linear narrative, nor a psychology or behavioral science textbook. It is a map—a structured, visual, and accessible reference for exploring over 200 cognitive biases and heuristics. Think of it as a behavioral science field guide: something you can consult in the middle of a problem, in the aftermath of a questionable decision, or during a conversation that has clearly gone sideways. It is also designed to be read non-sequentially. You can start anywhere, skip sections, follow your curiosity, or zoom in on a specific category. Some chapters are short and playful, others more technical. There is no single “correct” path through the material—only your path. How the Book Is Organized: The Periodic Table of Biases At the centre of this book is a visual organizing framework: the Periodic Table of Biases (see pp. 4-5). Inspired by the logic of the chemical periodic table, it arranges biases into 14 colour-coded categories, each corresponding to a particular cognitive or behavioral function—such as memory, attention, confidence, or belief. This taxonomy is not cosmetic. It reflects real distinctions in how the brain encodes, retrieves, interprets, and acts upon information. It allows readers to see not just what each bias is, but how related biases group together—and occasionally, how they clash. The colour-coded Periodic Table presented in this book is your navigation tool. You might use it in several ways: • Dip in and out: Read an entry when you encounter a new term in a podcast, a meeting, or a news article. • Compare categories: Explore how Confidence Effects differ from Belief-Based Biases, or how Attention effects interact with Memory effects. • Follow a colour trail: Pick one functional group—like Intertemporal Choice—and examine how those biases shape your decisions over time. • Trace cognitive collisions: Use the table to uncover where multiple biases might reinforce or contradict each other in the same scenario. The visual organization allows for both specificity and synthesis: zoom in on a single phenomenon or trace broader psychological patterns across domains. 1

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Level Individual

Functional Domain Personal Characteristics

Conceptual Frame Being human is not irrational

Limitations of the Brain

Mind is flat

Judgement

Decision making

Social

Category

Definition

Human Characteristics

Stem from fundamental traits of human cognition and behavior— such as innate preferences. These are deeply rooted effects that reflect what it means to be human (e.g., Ambiguity attitude, Risk attitude).

Memory Effects

Reflect the selective and reconstructive nature of memory. What we remember, misremember, or forget often depends on emotional salience, recency, or context (e.g., False memory, Lag effect).

Attention Effects

Influence what we pay attention to, what we ignore, and how salience affects our perceptions. These effects help us filter overwhelming stimuli, but they can also distort reality by amplifying certain cues over others (e.g., Attentional bias, Focusing effect).

Intertemporal Choice

Reflect our struggle to manage short-term vs. long-term trade-offs. Often discussed in the context of self-control, patience, and reward delay (e.g., Hyperbolic discounting, Present bias).

Information Processing

Arise from the shortcuts and simplifications our brains make when processing data. They often affect how we assess causality, complexity, or correlations, and are central to understanding flawed reasoning (e.g., Default effect, Decoy effect).

Confidence Effects

Relate to how confident we are in our knowledge or abilities. Often, these biases cause us to overestimate what we know or how accurately we can predict future events (e.g., Overconfidence effect, Dunning-Kruger effect).

Methodology Biases

Concern how research is designed, interpreted, or reported. They highlight pitfalls in scientific practice that can mislead evidencebased understanding (e.g., Outcome bias, Planning fallacy).

Value Processing

Cover how we evaluate worth, outcomes, and trade-offs. It includes distortions in how we perceive cost-benefit ratios or assign utility to different options (e.g., Endowment effect, Loss aversion).

Belief is reality

Belief-Based Biases

Reflect how existing beliefs shape our interpretation of new information. They often lead us to seek, recall, or prioritise evidence that aligns with what we already believe, reinforcing preconceptions (e.g., Illusion of control, Hindsight bias).

Inferences are key

Choice Under Risk/Uncertainty

Capture instances when individuals make decisions with incomplete or uncertain/ambiguous information. These effects describe how people estimate probabilities, weigh outcomes, and respond to risk. (e.g., Violation of transitivity, Ellsberg paradox).

Creativity Effects

Influence how we generate novel ideas or solve problems as well as reveal constraints and illusions in how humans explore alternatives or reinterpret problems (e.g., Anthropocentric thinking, Functional fixedness).

Sentiment and Senses

Reflect the influence of emotion and sensory input on decisionmaking. These include phenomena like visceral reactions, emotional contagion, and affective heuristics (e.g., Impact bias, Empathy gap).

Interaction effects

Interpersonal Effects

Deal with how we perceive, evaluate, or react to other individuals. They affect things like trust, attribution of intent, and responses to feedback (e.g., Halo effect, Authority bias).

Collective effects

Populational Group Effects

Everything is relative

Colour Code

and

Manifest at the group level—through norms, demographic differences, or identity dynamics. They often relate to broader cultural or structural phenomena (e.g., Groupthink, Herding).

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Why the Groupings Matter

The categories in the table are not arbitrary. They are based on a synthesis of behavioral science, cognitive psychology, decision theory, and neuroscience. The goal is both cognitive and didactic: • Cognitive-functional: Each group reflects a different mental operation—memory, attention, value evaluation, social reasoning, etc. • Didactic: By clustering related biases, the goal is to help you understand why these distortions occur and how they interrelate. These groupings also help you locate patterns that might otherwise go unnoticed. For example: • Belief-Based Biases and Information Processing may jointly influence how we assess new data. • Confidence Effects and Social Interaction Biases often operate together in leadership settings. • Group Effects can exaggerate or suppress individual-level biases, leading to very different collective outcomes. Applying This Book in Real Life This book is meant to be practical. It can be used in multiple contexts: • Personal growth: Spot thinking traps, understand internal conflict, or reflect on why you regret some choices but not others. • Professional settings: Improve decision-making, product design, negotiation, or team dynamics by identifying predictable distortions in perception and evaluation. • Community and policy: Detect the group-level dynamics—such as conformity, bias propagation, or polarisation—that affect institutions, campaigns, or public discourse. Every entry is written with accessibility in mind. Some biases are robustly supported by decades of research; others are more contested. For transparency, we flag replicability and include curated references at the end of each chapter for those who want to explore further. All terminology—bias names, effects, constructs—is preserved from the original academic literature. While some may sound clunky, outdated, or even insensitive, we retain them for traceability. Where appropriate, we provide commentary or context. We ask readers to interpret terms like Cross-Race Effect or Mind is Flat not as value judgments, but as labels rooted in specific theoretical traditions. Start Anywhere. Go Everywhere. This book does not assume you are irrational. It assumes that you are human. Whether you’re a student trying to make sense of a confusing lecture, a manager frustrated by groupthink, a policy analyst searching for better interventions, or simply a curious mind wondering why people click on fake news—they are all here. So open to any page. Pick a category. Follow a colour-coded category or consult the alphabetical index at the end of this book. Let the table be your compass. And the next time someone says, “That’s just a bias,” you’ll know exactly which one—and why it matters. Happy exploring! 3

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RISK ATTITUDE Risk attitude refers to an individual's or organization's disposition towards risk, which influences how they perceive, evaluate, and respond to uncertain situations. do you keep buying lottery tickets? Winning anything significant is practically impossible. It's a fantasy! Can't you see that?" he exclaimed. Ellie, unfazed and cheerful, replied, "Maybe you're not the risk-taking type, but I am. I believe in my luck; we just view risk differently!" "It's not about risk attitudes—it's about common sense," Rooney argued. "Buying lottery tickets is simply irrational." Ellie was curious. "How so?" Rooney explained, "Consider this: if I offered you a lottery ticket with a 50% chance of winning $100, the 'risk-free cash equivalent' would be $50. That's $100 times the 0.5 probability. Risk-taking people who enjoy risk might pay more than $50, while risk-averse people who don't like risk would pay less. It's normal and reflects their attitude towards risk. However, buying a ticket with a one in a million shot isn't just odd, it's downright foolish." Ellie shrugged, "Call it foolish, but I still feel lucky today." Rooney sighed in resignation. "You're impossible!" Rooney was visibly frustrated with Ellie. "Why 14

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bold move was the decision to operate at low margins for extended periods to gain market share, which eventually led to Amazon becoming one of the largest and most influential companies in the world.

About: Risk attitude refers to how people or organizations respond to situations where the outcomes are uncertain, but the probabilities are known. For example, some people avoid taking risks, preferring safer options, while others are more willing to take chances for potential rewards. This concept has been studied for centuries, starting with Daniel Bernoulli in 1738, who explained that people value outcomes based on their personal satisfaction (or utility), not just monetary gain (Bernoulli, 1738). Later, John von Neumann and Oskar Morgenstern (1944) formalized this idea into expected utility theory (von Neumann and Morgenstern, 1944). Daniel Kahneman and Amos Tversky (1979) expanded this with prospect theory, showing how people weigh probabilities to make decisions (Kahneman and Tversky, 1979). People and organizations can be risk-averse, risk-neutral, or risk-seeking, depending on how they weigh potential losses against potential gains. These attitudes profoundly impact financial decisions, business strategies, and everyday choices (Loewenstein et al., 2001; Weber and Milliman, 1997).

Reproducibility: Research into risk attitude has been replicated across various contexts (e.g., Dohmen et al., 2011). Studies often reveal that risk-averse individuals are more prevalent in the general population, though the proportion of risk-seekers can rise significantly in specific contexts like gambling or entrepreneurship. Additionally, cultural factors influence risk attitudes; e.g., societies with higher uncertainty avoidance tend to display greater risk aversion, while those with lower uncertainty avoidance may exhibit more riskseeking behavior (Shou et al., 2023). Although earlier economic research suggested that risk attitudes are stable traits, newer evidence has shown that they are often context-dependent (Loomes and Pogrebna, 2014). Selected References Bernoulli, D. (1738). Specimen theoriae novae de mensura sortis. Commentarii Academiae Scientiarum Imperialis Petropolitanae, 5, 175–192. (Translated in 1954 as “Exposition of a New Theory on the Measurement of Risk” in Econometrica, 22(1), 23–36). Dohmen, T., Falk, A., Huffman, D., Sunde, U., Schupp, J., & Wagner, G. G. (2011). Individual risk attitudes: Measurement, determinants, and behavioral consequences. Journal of the European Economic Association, 9(3), 522–550. Kahneman, D., & Tversky, A. (1979). Prospect theory: An analysis of decision under risk. Econometrica, 47(2), 263–292. Loewenstein, G. F., Weber, E. U., Hsee, C. K., & Welch, N. (2001). Risk as feelings. Psychological Bulletin, 127(2), 267–286. Loomes, G., & Pogrebna, G. (2014). Measuring individual risk attitudes when preferences are imprecise. Economic Journal, 124(576), 569–593. Shou, Y., Olney, J., & Wang, M. C. (2023). Cross-cultural assessment and comparisons of risk tolerance across domains. Current Psychology, 42(18), 15368–15380. Slovic, P. (1995). The construction of preference. American Psychologist, 50(5), 364–371. von Neumann, J., & Morgenstern, O. (1944). Theory of games and economic behavior. Princeton University Press. Weber, E. U., & Milliman, R. A. (1997). Perceived risk attitudes: Relating risk perception to risky choice. Management Science, 43(2), 123–144

Trivia Example: One illustration of risk-related behavior can be seen in the world of stock trading. For instance, investors who are risk-averse tend to prefer bonds or dividend-paying stocks with predictable returns, whereas risk-seeking investors might gravitate towards volatile tech stocks or options trading, where the potential for high returns is accompanied by significant risk (Slovic, 1995). Business Example: A well-known example of a company that exhibited a risk-seeking attitude is Amazon. Under the leadership of Jeff Bezos, Amazon pursued high-risk strategies that defied conventional business norms. This included aggressive investments in new technologies and business models, such as cloud computing through Amazon Web Services (AWS) at a time when this market was still in its infancy. Another 15

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AUTHORITY BIAS The tendency to attribute greater accuracy to the opinion of an authority figure (unrelated to its content) and be more influenced by that opinion. "Hey, want to catch a movie this weekend?" Ellie asked. "There's this new one with George Clooney. My brother saw it yesterday and really liked it." "No, I'm not interested," Rooney replied bluntly. "Why not?" "I read a review by this blogger, @RKfilms, and they completely trashed it. Trust me, it's not worth it!" "But it has an 86% rating on Rotten Tomatoes!" Ellie countered. "Even if it had 100%! If @RKfilms says the movie's rubbish, then it must be!"

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healthcare, patients frequently over-rely on their doctors’ authority, sometimes at the expense of exploring alternative or complementary treatments (Epstein and Street, 2011).

About: Authority bias refers to the tendency to attribute more weight and credibility to the opinions or actions of authority figures, often leading to uncritical acceptance of their directives. This bias is deeply rooted in social hierarchies and evolutionary psychology, where deference to authority could enhance survival and cohesion within groups (Milgram, 1963). However, in modern contexts, this predisposition often overrides rational evaluation, influencing decisions in domains such as medicine, education, finance, and workplace dynamics. Authority bias can result in both positive and negative outcomes: while it fosters trust and efficiency in hierarchical systems, it may also lead to poor decision-making when individuals defer to authority without independent scrutiny.

Reproducibility: The prevalence of authority bias has been consistently demonstrated in behavioral science research (e.g., Li et al., 2025). Milgram’s (1963) seminal study has been replicated across decades and cultural contexts, confirming the universal influence of perceived authority. Subsequent studies, such as Burger (2009), showed similar levels of compliance, even with updated ethical standards. In medical contexts, research by Frosch et al. (2012) highlights patients’ reluctance to challenge physicians’ recommendations, even when the advice may not align with their preferences. Cross-cultural research by Bond and Smith (1996) suggests that authority bias is particularly pronounced in collectivist cultures, where deference to hierarchical structures is socially reinforced. These findings emphasize the global relevance and persistence of authority bias across varied domains and scenarios.

Trivia Example: The classic Milgram experiment vividly illustrates authority bias. Participants were instructed by a figure of authority—a researcher in a lab coat—to administer what they believed were electric shocks to another person. Despite clear signs of distress from the supposed recipient, most participants continued to obey the instructions, demonstrating the profound influence of perceived authority on moral reasoning (Milgram, 1963). Variations of this experiment have consistently replicated similar findings, underscoring the robustness of the phenomenon (Burger, 2009).

Selected References

Bond, R., & Smith, P. B. (1996). Culture and conformity: A metaanalysis of studies using Asch’s (1952b, 1956) line judgment task. Psychological Bulletin, 119(1), 111–137. Burger, J. M. (2009). Replicating Milgram: Would people still obey today? American Psychologist, 64(1), 1–11. Epstein, R. M., & Street, R. L. (2011). The values and value of patient-centered care. Annals of Family Medicine, 9(2), 100–103. Frosch, D. L., May, S. G., Rendle, K. A. S., Tietbohl, C., & Elwyn, G. (2012). Authoritarian physicians and patients’ fear of being labeled “difficult.” Health Affairs, 31(5), 1030–1038. Li, Y., Guo, X., Gao, J., Chen, G., Zhao, X., Zhang, J., ... & Wei, X. (2025, July). LLMs Trust Humans More, That’sa Problem! Unveiling and Mitigating the Authority Bias in RetrievalAugmented Generation. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers) (pp. 28844-28858). Milgram, S. (1963). Behavioral study of obedience. Journal of Abnormal and Social Psychology, 67(4), 371–378. Thaler, R. H., & Sunstein, C. R. (2008). Nudge: Improving decisions about health, wealth, and happiness. Yale University Press.

Business Example: In the corporate world, authority bias can stifle innovation and critical thinking. For instance, employees may defer to senior executives’ opinions during meetings, even when they possess more accurate or innovative ideas. The 2008 financial crisis exemplifies this bias at scale, as many financial institutions adhered unquestioningly to the risky strategies endorsed by influential CEOs, exacerbating systemic failures (Thaler and Sunstein, 2008). In 345

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INDEX Page Number Actor-observer bias (Ac)

346

Allais Paradox: Common Consequence (Cc)

302

Allais Paradox: Common Ratio (Cr)

304

Ambiguity attitude (Aa)

Ambiguity effect (Ae)

300

Anchoring or focalism (Af)

116

Anthropocentric thinking (An)

316

Anthropomorphism or personification (Am)

318

Attentional bias (At)

118

Attribute substitution (As)

148

Automation bias (Au)

150

Authority bias (Ab)

344

Availability cascade (Av)

416

Availability heuristic (Ah)

Backfire effect (Bf)

240

Bandwagon effect (Bw)

418

Base rate fallacy or Base rate neglect (Br)

154

Belief bias (Bb)

242

Ben Franklin effect (Bn)

380

Berkson paradox (Bk)

152

Bias blind spot (Bs)

382

Bizarreness effect (Be)

Cheerleader effect (Cd)

348

Choice-supportive bias (Ch)

Clustering illusion (Ci)

156

Compassion fade (Cm)

384

Confirmation bias (Cf)

244 438

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Congruence bias (Co)

196

Conjunction fallacy (Cj)

158

Conservatism or Regressive Bias (Cn)

Conservatism or Belief Revision (Cv)

248

Consistency bias (Cb)

Context effect (Ce)

Continued influence effect (Cl)

246

Contrast effect (Ct)

Courtesy bias (Cu)

388

Cross-race effect (Cs)

Cryptomnesia (Cy)

Curse of knowledge (Ck)

386

Declinism (De)

Decoy effect (Dy)

164

Default effect (Dt)

162

Defensive attribution hypothesis (Db)

350

Denomination effect (Df)

216

Disposition effect (Ds)

218

Distinction bias (Di)

160

Dread aversion (Da)

322

Dunning-Kruger effect (Dk)

186

Duration neglect (Du)

130

Egocentric bias (individual) (Eg) Egocentric bias (social) (Ec)

34 352

Ellsberg paradox (Ep)

306

Empathy gap (Em)

324

End-of-history illusion (Eh)

252

Endowment effect (Ew)

220

Exaggerated expectation (Ex)

254

Experimenter's or expectation bias (Ee)

250

439

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Extrinsic incentives bias (Et)

354

Fading affect bias (Fa)

False consensus effect (Fc)

356

False memory (Fm)

False uniqueness bias (Fu)

360

Focusing effect (Fe)

120

Forer effect or Barnum effect (Fb)

256

Form function attribution bias (Ff)

258

Framing effect (Fr)

166

Frequency illusion or Baader-Meinhof effect (Fi)

122

Functional fixedness (Fn)

320

Fundamental attribution error (Fd)

358

Gambler's fallacy (Gf)

132

Generation/Self-generation effect (Gs)

Google effect (Go)

Group attribution error (Ga)

420

Groupthink (Gt)

422

Halo effect (Ha)

362

Hard-easy effect (Hy)

188

Herding (Hr)

424

Hindsight bias (Hb)

260

Hostile attribution bias (Hs)

390

Hot-hand fallacy (Hh)

262

Humor effect (He)

Hyperbolic discounting (Hd)

134

IKEA effect (Ie)

222

Identifiable victim effect (If)

392

Illicit transference (It)

200

Illusion of asymmetric insight (Ii)

364

Illusion of control (Ic)

264 440

BIG BAD BIAS BOOK

Illusion of external agency (Ix)

370

Illusion of transparency (Ip)

366

Illusion of validity (Iv)

268

Illusory correlation (Il)

266

Illusory superiority (Io)

368

Illusory truth effect (Iy)

270

Impact bias (Im)

326

Implicit association (Ia)

Information bias (Ib)

168

Ingroup bias (Ig)

426

Insensitivity to sample size (Is)

198

Interoceptive bias (In)

328

Irrational escalation/Escalation of commitment (Ir)

224

Just-world hypothesis (Jw)

372

Lag effect (Le)

Law of the instrument (Li)

202

Levels-of-processing effect (Lp)

Leveling and sharpening (Ls)

Less-is-better effect (Lb)

170

Licencing effect

136

List-length effect (Ll)

Look-elsewhere effect (Lk)

204

Loss aversion (La)

226

Mere exposure effect (Mx)

272

Misinformation effect (Me)

Modality effect (Mo)

Money illusion (Mi)

228

Mood-congruent memory bias (Mc)

Moral credential effect (Ml)

138

Moral luck (Mr)

374 441

BIG BAD BIAS BOOK

Naïve cynicism (Na)

376

Naïve realism (Nr)

378

Negativity bias or Negativity effect (Ne)

Neglect of probability (Ng)

172

Next-in-line effect (Nx)

Normalcy bias (Nb)

274

Not invented here (Nh)

230

Observer-expectancy effect (Ob)

206

Omission bias (Om)

276

Optimism bias (Op)

330

Ostrich effect (Os)

278

Outcome bias (Ot)

208

Outgroup homogeneity bias (Oh)

428

Overconfidence effect (Oc)

190

Pareidolia (Pa)

280

Parkinson's law of triviality (Pk)

174

Part-list cueing effect (Pc)

Peak-end rule (Pr)

Pessimism bias (Pb)

192

Picture superiority effect (Ps)

Planning fallacy (Pf)

210

Positivity effect (Socio-emotional selectivity) (Po)

Present bias (Pt)

144

Primacy, recency & serial position effect (Pi)

Pro-innovation bias (Pv)

332

Processing difficulty effect (Pd)

Projection bias (Pj)

142

Pseudocertainty effect (Pe)

232

Pygmalion effect

394

Reactance (Rc)

334 442

BIG BAD BIAS BOOK

Reactive devaluation (Rd)

282

Recency illusion (Ri)

140

Regressive bias (Rg)

176

Reminiscence bump (Rb)

108

Restraint bias (Re)

194

Rhyme as reason effect (Rr)

286

Risk attitude (Ra)

Risk compensation/Peltzman effect (Rp)

284

Salience bias (Sa)

336

Selection bias (Sb)

124

Selective perception (Sp)

292

Self-relevance effect (Sr)

Self-serving bias (Ss)

404

Semmelweis reflex (Sm)

290

Sexual over/underperception bias (Sx)

406

Shared information bias (Sh)

398

Singularity effect (Si)

400

Social comparison bias (So)

430

Social desirability bias (Sd)

396

Source confusion (Sc)

Spacing effect (Sp)

Spotlight effect (Sl)

St Petersburg paradox (St)

308

Status quo bias (Sq)

294

Stereotypical bias (Sy)

Stereotyping (Se)

432

Subadditivity effect (Su)

180

Subjective validation (Sj)

288

Suffix effect (Sf)

Suggestibility (Su)

94 443

BIG BAD BIAS BOOK

Surrogation (Sg)

212

Survivorship bias (Sv)

178

System justification (Sn)

402

Tachypsychia (Tp)

102

Telescoping effect (Tl)

100

Testing effect (Te)

Third-person effect (Td)

434

Time-saving bias (Tm)

146

Tip of the tongue (Tt)

106

Trait ascription bias (Ta)

408

Travis syndrome (Ts)

104

Ultimate attribution error (Ua)

410

Unit bias (Ub)

234

Verbatim effect (Ve)

112

Violation of dominance (Vd)

314

Violation of independence (Vi)

312

Violation of transitivity (Vt)

310

von Restorff effect (Rf)

110

Weber-Fechner law (Wf)

214

Well-travelled road effect (Wr)

182

Women are wonderful effect (Ww)

436

Worse-than-average effect (Wa)

412

Zeigarnik effect (Ze)

114

Zero-risk bias (Zr)

296

Zero-sum bias (Zs)

184

444

BIG BAD BIAS BOOK

NOTES

445

BIG BAD BIAS BOOK

446