Measurement and meaning of head movements in everyday face-to-face communicative interaction.

Methodological approaches in which data on nonverbal behavior are collected usually involve interpretative methods in which raters must identify a set of defined categories of behavior. However, present knowledge about the qualitative aspects of head movement behavior calls for recording detailed transcriptions of behavior. These records are a prerequisite for investigating the function and meaning of head movement patterns. A method for directly collecting data on head movement behavior is introduced. Using small ultrasonic transducers, which are attached to various parts of an index person's body (head and shoulders), a microcomputer determines receiver-transducer distances. Three-dimensional positions are calculated by triangulation. These data are used for further calculations concerning the angular orientation of the head and the direction, size, and speed of head movements (in rotational, lateral, and sagittal dimensions). Further analyses determine relevant changes in movements, identify segments of movements, and classify the quantifications of movement patterns. The measured patterns of nonverbal behavior can be accurately related to features of verbal communication and other time-related variables (e.g., psychophysiological measures). To estimate the possible meanings of behavioral patterns, a heuristic is proposed that includes the situational context as the basis of interpretation.