SOME EXPERIMENTS ON THE RECOGNITION OF SPEECH, WITH ONE AND WITH TWO EARS

Cherry, E. C. (1953). Some Experiments on the Recognition of Speech, with One and with Two Ears. Journal of the Acoustical Society of America, 25, 975–979. https://doi.org/10.1121/1.1907229

This experiment was developed into sections. The recognition in phrases, the highly likely errors and transposition, and the consistency of any initial grammatical errors were the key criterion focused in every sample. The result was reported progressively as the experiment went on.

How can people manage to concentrate on listening to someone speaking when there was another person speaking at the same time? In normal circumstances, environmental factors and manual solutions could contribute to achievement such as an uneven volume of speeches due to direction and distance differences or using visual ability in addition to read the speaker’s lips. However, in this experiment, all of those assists were filtered out. All speeches were recorded on tape and the subject listened to them via balanced headphones. Playbacks the record was permitted but jotting the messages down was not. The subject’s task was repeating one of two speeches after listening to them both being mixed in one record. He finally leaked some mistakes in transposition where it was likely. The subject was, to some extent, reportedly struggle with some specific phrases. He was later allowed to write down what he heard. He found the test was suddenly easier. This could be interpreted that long-term memory aid played a role in this situation.

This time, the researcher switched to using inseparable speeches generated by selected clichés found in newspapers then joined them with simple conjunctions. As the definition of the word cliché itself, it was familiar and resulted as an easier way for the subject to predict and recognise a full phrase. This was suggested that simply structured phrases with a small amount of unfamiliar lexicon could be readily constructed.

What about one speech to the right ear and another to the left? The researcher had done with mixed record presented to both ears. The subject was fed through headphones with two distinct speeches, one to his right ear and another to his left ear, wellbalanced. His task was to repeat either passage at the same time as the hearing. As a result, he could decide to listen to one speech over another and switched back and forth. He recognised all words. Although, he had tiny comprehension of the passage as a whole. It implicated that to be able to concentrate on one speech over another, one could attempt by turning towards the source to have the passage dominantly only on one ear and lessen the sound quality on another one rather than receiving the passage evenly to both ears, which caused less opportunity to gain either.

Let’s deliberate on the speech that was left unfocused. Was the subject even aware of the quality of the rejected speech when all concentration was applied to the chosen one on another ear? Now, the subject listened to passages selected from newspapers on his right ear. On his left ear, he was fed with a different type of sounds, included human voices in from both genders normal and reversed ones, and meaningless oscillator sound. The result was the subject successfully recognised what kind of rejected sound he was hearing but failed to give specific details about them.

Now, the researcher escalated the task to the timing difference. Because of how the subject engaged two signals before making a decision about which signal to listen and which was to be rejected still left unexplored. Two identical speeches were fed to the subject’s both ears in a delay to each other. They started with a very long delay between them, which revealed the subject used the tuning in meaning, and the delay slowly became shorter, the tuning in sound applied, then finally overlapped in timing. Discovered that the subject was aware of the details of rejected speech when identical speeches were the case, as opposed to earlier tests that unidentical speeches were used. ■

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