Researchers think that speech is not entirely planned, and that people know what they are saying in part through hearing themselves speak.
If you think you know what you just said, think again. People can be tricked into believing they have just said something they did not, researchers report this week.The dominant model of how speech works is that it is planned in advance - speakers begin with a conscious idea of exactly what they are going to say. But some researchers think that speech is not entirely planned, and that people know what they are saying in part through hearing themselves speak.
So cognitive scientist Andreas Lind and his colleagues at Lund University in Sweden wanted to see what would happen if someone said one word, but heard themselves saying another.
In Lind's experiment, participants took a Stroop test - in which a person is shown, for example, the word ‘red’ printed in blue and is asked to name the colour of the type (in this case, blue). During the test, participants heard their responses through headphones. The responses were recorded so that Lind could occasionally play back the wrong word, giving participants auditory feedback of their own voice saying something different from what they had just said. Lind chose the words 'grey' and 'green' (grå and grön in Swedish) to switch, as they sound similar but have different meanings.
After participants heard a manipulated word, a question popped up on the screen asking what they had just said.
When the voice-activated software got the timing just right - so that the wrong word began within 5–20 milliseconds of the participant starting to speak - the change went undetected more than two-thirds of the time. And in 85% of undetected substitutions, the participant accepted that they had said the wrong word, indicating that speakers listen to their own voices to help specify the meaning of what they are saying.
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Source material from Scientific American