The relevance of body motion cues to both functional and dysfunctional communicative behavior

This study assessed the extent ot which a speaker's visible, spontaneous body movements can contribute to the speech process. An experiment was conducted where subjects responded to videotaped verbal stimuli in one of three conditions (audiovisual, audiovisual without lip and facial cues, and audio alone) over four signal-to-noise ratios. The results indicated that: (1) visual cues can at times significantly improve comprehension scores, even with lip-facial cues not present; (2) visual cues significantly retard decay of comprehension as noise is increasingly introduced; (3) visual cues assist the comprehension of certain types of verbal segments, regardless of the information content expressed in those types of segments. A model of the bimodal aspect of the speech process is developed which illustrates both the cognitive and message-content dimensions. Possible future applications and research objectives are discussed in terms of normal and dysfunctional communicative behavior.