‘The best research has failed to show that people who stutter, as a group, are more neurotic or have more psychological disorders than those who do not stutter. We do not think that children begin stuttering because of any serious emotional difficulties.’
What, then, causes stuttering? The only honest answer is that nobody really knows. Various brain scanning studies have identified a few interesting correlations, such as abnormal circuitry in the basal ganglia. (Damage to the basal ganglia can also trigger sudden adult onset stuttering.) Interestingly, stutterers seem to show increased activity in areas of the brain devoted to speech movements, such as the primary motor cortex. It’s as if the stammer is triggered by an excess of planning, much like the yips in golf. What’s important to note is that these differences aren’t triggered by deep-seated emotional problems. Instead, they are mostly mechanical defects, rooted in the machinery of translating our thoughts into a set of complex bodily movements.