Abstract

We produce gestures spontaneously not only when we speak (“co-speech gestures”), but also when we think without speaking (“co-thought” gestures). I will first present the evidence that co-speech gestures are highly sensitive to what goes on in speech production. For example, our cross-linguistic study has indicated that gestural representation of motion events varies as a function of the linguistic structures used to encode motion events. Furthermore, gestures are produced more frequently when it is difficult to organise ideas for linguistic expression. Despite these pieces of evidence for a tight link between gesture and language, there is also evidence for independence. I will present the evidence that gesture production is dissociable from speech production based on the data from split-brain patients. Furthermore, I will also present the results from experiments (with healthy participants), which show important parallelisms between co-speech gestures and co-thought gestures, suggesting that these two types of gestures are produced from the same mechanism. I will conclude that gestures are produced from a mechanism that is inherently independent from, but highly interactive with, the speech production process.