Gesture - Volume 6, Issue 1, 2006

Despite various theories about the exact origin of gestures in speech production, researchers generally accept that gesture and speech constitute the product of a single unit of thought within the speaker. On the other hand, what I call gestural mimicry requires consideration of factors outside such speaker-internal coupling of gesture and speech. Through detailed analysis of a joint narration task and casual conversation in a dyad, I will show that, once perceived and decoded by a partner, the form–meaning relationship of a speaker’s gesture can become part of the common ground of understanding between the participants. In gestural mimicry, communicativity is observed in the way a speaker’s spontaneous gesture shapes the subsequent gestural move of the interlocutor. With a recurrence of gestural features across speakers, image construal through gesture becomes an interactional phenomenon. That is, gesture as well as speech provides an interactional resource for co-constructing talk.

Although some studies have demonstrated that imagistic gestures do communicate significant amounts of information none have attempted to analyze the significance of that information for the linguistic account within which it is embedded. This study focuses on the semantic dimension size and in a corpus of narratives identifies every single instance of size information and identifies whether this size information is encoded in speech, in gesture, or in speech and gesture. Crucially, it considers the judged relative importance of each instance of size information. It was discovered that high importance size information was significantly more likely to be encoded in gesture rather than in speech, whereas low importance size information was more likely to be encoded in speech rather than in gesture. This suggests that speakers may vary what information is encoded gesturally, according to its salience for the overall meaning to be conveyed. This result has major implications for the conceptualization of how gesture and speech work together in everyday talk.

It has been claimed that the perceptual accuracy with which people comprehend distal pointing gestures is low. But this claim is at odds with research showing that detection of other indexical signals, e.g., eye gaze, is very accurate. We conducted three experiments to assess people’s detection accuracy of targets of distal pointing gestures, using a paradigm adapted from the study of eye gaze. Pairs of people were seated next to each other. One person pointed at targets among 70 points arranged in a horizontal (Experiment 1) or vertical line (Experiment 2). The other person guessed the target. Bias in detection was substantially less than previously shown (approximately 3° in vertical and horizontal conditions), and comparable to levels of accuracy for eye gaze detection. Furthermore, and contrary to previous research, detection accuracy was lower for peripheral targets than for central ones. Experiment 3 replicated Experiments 1 and 2 within one study and further demonstrated that partial occlusion of the pointing arm (from shoulder to elbow) did not adversely affect accuracy.