The tradeoff hypothesis in the speech–gesture relationship claims that (a) when gesturing gets harder, speakers will rely relatively more on speech, and (b) when speaking gets harder, speakers will rely relatively more on gestures. We tested the second part of this hypothesis in an experimental collaborative referring paradigm where pairs of participants (directors and matchers) identified targets to each other from an array visible to both of them. We manipulated two factors known to affect the difficulty of speaking to assess (...) their effects on the gesture rate per 100 words. The first factor, codability, is the ease with which targets can be described. The second factor, repetition, is whether the targets are old or new (having been already described once or twice). We also manipulated a third factor, mutual visibility, because it is known to affect the rate and type of gesture produced. None of the manipulations systematically affected the gesture rate. Our data are thus mostly inconsistent with the tradeoff hypothesis. However, the gesture rate was sensitive to concurrent features of referring expressions, suggesting that gesture parallels aspects of speech. We argue that the redundancy between speech and gesture is communicatively motivated. (shrink)

Past research has suggested that those spontaneous movements of the human hand made during talk convey significant semantic information over and above the speech, at least when the unit of speech analyzed is the individual clause. However, no previous research has tested whether this information is represented linguistically elsewhere in the narrative . The first study, reported here, uses an experimental procedure to identify which specific imagistic gestures add semantic information to the speech. The second study analyzes whether the specific (...) gestures still do this when respondents hear the whole narrative. It was found that two thirds of the semantic information, thought to be carried by the gestures, is, in fact, represented in the linguistic discourse, or is inferable from it. However, one third of the additional semantic information contained in the gestures is not represented linguistically in the narrative nor is it inferable from it. In other words, a proportion of the imagistic gestures that accompany speech are absolutely critical to semantic communication. (shrink)