Nothing seems more automatic than speech. We produce an estimated 150 words a minute, and make a mistake only about once every 1,000 words. We stay on track, saying what we intend to, even when other words distract us—from the radio, say, or a road sign we pass while driving.
An upcoming study in Psychological Science, a journal of the Association for Psychological Science, shows for the first time why we so rarely speak those irrelevant words: We have a “verbal self-monitor” between the mental production of speech and the actual uttering of words that catches any irrelevant items coming from outside of the speaker.
The study made use of the fact that the self-monitor “cares about context,” and is “especially sensitive” to intercept words that might be inappropriate in a particular social situation, says experimental psychologist Elisah Dhooge, who conducted the study with University of Ghent colleague Robert J. Hartsuiker.
To investigate how this happens, the researchers conducted two experiments, one focusing on the effect of taboo words on speed of speech and the other on accuracy of speech. First, 20 participants were shown a picture on the screen, onto which an irrelevant word appeared, superimposed. Each picture was shown once with a neutral word, once with a taboo one. The word pairs were matched for length and semantic and phonetic relationship to the picture, but neither word was the right label for the picture. The participants were then instructed to name the pictures, not worrying about errors, and were continually encouraged to go faster.
The second experiment was the same, except that now subjects were simply asked to name the picture, trying to be as fast and as accurate as possible.
The results: In Experiment 1, the participants made fewer errors, such as naming the word instead of the picture, with the taboo words than the neutral ones. In Experiment 2, they paused longer before naming the picture with the taboo word superimposed. Their self-monitor, say the authors, was more “stringent” when encountering an offensive word. The monitor, says Dhooge, plays a crucial role in speech. “We are bombarded by irrelevant stimuli constantly. But somehow your system has a way of filtering all that out.” “We have shown that it is the monitor that prevents you from actually saying these words out loud.” We can also thank the speech monitor for saving us from a lot of red-faced moments.