Everyone makes mistakes when they speak. Up to 15 per cent of an average person's speech can contain dysfluencies. By listening to ourselves as we talk, auditing our output for hesitations, mispronunciations and the occasional wrongly selected word, we sometimes catch the mistakes. Our research team (at Edinburgh University and Queen Margaret University College) believes that people who stammer listen to themselves too critically: they invest more mental effort in self-monitoring, and are particularly sensitive to errors. Attempting to correct an error can make the sound worse, leading to a vicious circle of repairing the repair they have just attempted.
Research has traditionally focused on the classification and prevention of stammering, tending to divide the population into people who stammer and those who do not. More recent approaches attempt to understand the stammering process itself, for example, whether it is caused by problems with the selection of sounds for speaking or with the programming and movement of the muscles that control speech. Such approaches suggest that people who stammer are fundamentally more likely to generate dysfluent speech, but they do not explain why people report having particularly good or bad days.
Despite the fact that it affects so many people, there is little research into stammering at present, and the British Stammering Association and other academic experts have lent us their support. However, due to interest in the television show Pop Idol we have had quite a few calls, so there may be better days ahead!
Gareth Gates, one of the finalists on the programme, is reported to be following the McGuire programme, which claims to successfully improve stammering. It appears to involve taking deep breaths before speaking and thinking about what you are saying. I do not think taking deep breaths would make any difference in itself, but concentrating on other things may help distract attention from self-monitoring, and the programme has had some notable successes. But in a highly stressful environment such as television it may be difficult to overcome a natural tendency to pay attention to how you sound. No wonder Gareth appears to have relapsed since last summer. The fact that he can sing very well has nothing much to do with his stammering. Singing is largely overlearned speech. It is not the first time he has uttered the words of the songs he sings. Every phrase is carried on a breath and his mind is on other things, such as smiling or holding the tune. This may also be true of acting. Nonetheless it is a scary proposition if you are forced to perform in front of a large audience. It probably depends on where your focus of attention is.
For our research we are using recordings of naturalistic dialogues between two people who are given maps of the same area that do not all have the same features on them. One person has to guide the other to a certain spot. There is some negotiation involved, for example, over whether to use east and west or right and left, but it does not tend to be explicit. From this database of dialogues between people who do not stammer we can confidently estimate the extent to which most people are dysfluent. We want to get people who stammer to do the same task. Do they make different types of mistakes? As far as we can tell from pilot studies, the proportion of mistakes is different, but the types are all replicated in normal speech, such as repeating the first consonant of a word.
We are going to play back dysfluent and fluent speech segments to people who do and do not stammer. From pilot studies, we predict that people who stammer will differentiate much more between the two types of speech. This is not surprising if we believe that they are more sensitive to errors in speech than others.
Martin Corley
Department of psychology
Edinburgh University