The human brain prevents us from drifting off when listening to boring people by “rewriting” monotonous speech to make it sound more interesting, scientists have found.Research has shown that people listening to dreary discussions cope by creating an “inner voice” to drown out the offending speech.
The study revealed the response is triggered the moment the brain hears “monotonously-spoken” words it feels should be more expressive.
The resulting increased brain activity points to the existence of an inner voice which creates “more vivid speech” as a replacement.
Dr Bo Yao, the principal author of the research, said: “You may think the brain need not produce its own speech while listening to one that is already available. But, apparently, the brain is very picky on the speech it hears.
“When the brain hears monotonously-spoken direct speech quotations which it expects to be more vivid, the brain simply ‘talks over’ the speech it hears with more vivid speech utterances of its own.
“By doing so, the brain attempts to optimise the processing of the incoming speech, ensuring more speedy and accurate responses.”
The study, entitled “Brain ‘Talks Over’ Boring Quotes”, was conducted by scientists at the University of Glasgow’s Institute of Neuroscience and Psychology.
Researchers scanned the brains of 18 participants using functional magnetic resonance imaging (fMRI) while they listened to audio clips of short stories containing direct or indirect speech quotations.
The direct speech heard, for example when Mary said: “That film was terrible, I’ve never been so bored in my life”, were spoken either “vividly” or “monotonously”.
Changes to oxygen levels in the blood demonstrated that activity in areas of the brain’s auditory cortex, which deals with human speech, increased when people listened to monotonously-spoken direct speech quotes. Scientists speculate that this is likely to reflect the existence of an inner voice.
Last year, research conducted by the same scientists found that the brain can also create an inner voice when people read silently to themselves.
Professor Christopher Scheepers, a joint author of the study published in the NeuroImage journal this month, said: “Direct speech quotations are generally assumed to be more vivid and perceptually engaging than indirect speech quotations as they are more frequently associated with depictions of voices, facial expressions and co-speech gestures.
“When the brain does not receive actual stimulation of auditory speech during silent reading, it tends to produce its own to enliven written direct speech quotations – a phenomenon commonly referred to as the ‘inner voice’.
“Now it appears the brain does the same even when listening to monotonously-spoken direct speech quotations.”
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