What you hear is what you get, like it or not

Melissa Vo. This election has been intense, in every sense of the word. At times, some of us might have wished to just shut out the images of angry faces and the sounds of hateful or uninformed utterances.

You could have closed your eyes, but you sadly cannot close your ears. It seems clear that this openness has the advantage that important auditory information (e.g., someone calling your name, the crying of your baby in the middle of the night, a fire alarm that urges you to get the hell out of here) can be detected even if unattended. However, being constantly “open” to your surroundings can have also detrimental effects.

Trying to ignore the bunch of snoring men with whom you share a dormitory in an Alpine hut can be difficult without earplugs. Or suppose you are sitting in a café trying to study for your next exam, while the guy at the table next to you is telling a friend about his trip to Canada, where he visited a maple farm. This conversation most probably will distract you from studying the next chapter on genome sequencing, which is annoying, since this is the reason you came to the café in the first place.

So being able to ignore irrelevant auditory input is often key if you want to focus on another task.

The detrimental effects of irrelevant auditory information have been studied extensively using the irrelevant speech paradigm in which participants usually try to memorize a list of items, while either speech, sounds, or white noise is played to test how disruptive these are to your ability in recalling the exact order of the to-remembered items. There is ample evidence that when task-irrelevant speech is played while participants are trying to memorize a list of items, their recall performance of the sequence of items is reduced relative to a quiet control condition.

A study by Röer, Körner, Buchner, and Bell that recently appeared in the Psychonomic Bulletin & Review is taking a closer look at the irrelevant speech effect, but from a different viewpoint. People so far have mainly focused on how much of the to-be-remembered information is disrupted by irrelevant speech. The authors of this study were, however, more interested in the fate of the ignored information instead. So when you try not to listen to your neighbor’s conversation while studying for the next exam, how much of his blabbering will linger in your mind nevertheless. Would you suddenly feel the need to buy a maple bar?

How much of the information that you are trying to ignore is processed has been studied for more than half of a century. The classic experiments by Broadbent as well as Deutsch and Deutsch in the late 50s and early 60s are key ingredients in any textbook on attention. The cocktail party phenomenon, for instance, tells us that even if we want to ignore the content of another person’s conversation, we’d still notice that this person is mentioning our name.

Besides the special case of hearing your own name, it seems that the semantic content of irrelevant speech has no effect on serial recall performance. That is, playing irrelevant speech forward or backward does not change the disruptiveness of the irrelevant speech (see previous work by Jan Röer, the first author, of this article). The magnitude of the irrelevant speech effect is also independent of the degree of semantic similarity between items and distractors.

It is unknown, however, whether or not irrelevant speech is processed to a semantic level. The study by Röer and colleagues is targeting exactly this question.

The researchers presented irrelevant speech consisting of words, which — unbeknownst to the participants — were taken from different semantic categories (e.g., musical instrument, four-legged animal, type of fruit, etc.). To avoid ceiling effects, the eight most frequently produced words of those categories were not included. After finishing the irrelevant speech experiments, participants were asked whether they wanted to participate in a seemingly unrelated “norming study”. Here participants had to spontaneously produce exemplars from the semantic categories used in the first part of the experiment.

Concerning the results from the irrelevant speech experiment, participants made more errors in serial recall when words were played as compared to the quiet condition. This replicated the standard effect in the literature. More importantly, in the “norming study”, participants produced more category-exemplars from the previously ignored set than category-exemplars from a control set that was never presented, which can be taken as evidence for semantic priming. Overall, there was a 15% higher probability to produce a word that was previously presented as an auditory distractor, compared to the base value of producing the same word if it was not presented before.

In an additional control experiment, the authors found that the disruptive effect of speech played forward was not different from that of speech played backward. The lack of enhanced interference with forward presentation does not seem to imply that the content of the distractor words is not processed. Features of the irrelevant speech affect overt behavior in a subsequent task, confirming that the meaning of the irrelevant speech had been processed.

So beware, whatever you tried to ignore during the election might affect your behavior in the aftermath. Having listened to Donald Trump too much you may end up believing that immigrants are to blame for all sorts of society’s ills. Perhaps just shut off the TV and buy a falafel at your local Lebanese restaurant to convince yourself otherwise.

Study focused on in this post:

Röer, J. P., Körner, U., Buchner, A., & Bell, R. (2016). Psychonomic Bulletin & Review. doi: 10.3758/s13423-016-1186-3

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