Action, gesture, and sign represent unique aspects of human communication that use form and movement to convey meaning. Researchers typically use manual coding of video data to characterize naturalistic, meaningful movements at various levels of description, but the availability of markerless motion-tracking technology allows for quantification of the kinematic features of gestures or any meaningful human movement. We present a novel protocol for extracting a set of kinematic features from movements recorded with Microsoft Kinect. Our protocol captures spatial and temporal features, such as height, velocity, submovements/strokes, and holds. This approach is based on studies of communicative actions and gestures and attempts to capture features that are consistently implicated as important kinematic aspects of communication. We provide opensource code for the protocol, a description of how the features are calculated, a validation of these features as quantified by our protocol versus manual coders, and a discussion of how the protocol can be applied. The protocol effectively quantifies kinematic features that are important in the production (e.g., characterizing different contexts) as well as the comprehension (e.g., used by addressees to understand intent and semantics) of manual acts. The protocol can also be integrated with qualitative analysis, allowing fast and objective demarcation of movement units, providing accurate coding even of complex movements. This can be useful to clinicians, as well as to researchers studying multimodal communication or human-robot interactions. By making this protocol available, we hope to provide a tool that can be applied to understanding meaningful movement characteristics in human communication.
Keywords Communication . Methodology . Motion trackingHuman communication is intrinsically multimodal, consisting of not only speech but also visible communicative signals. Gesture, sign, and communicative actions (e.g., joint actions, demonstrations) are well-studied examples of communicative manual acts that can convey meaning in the presence or absence of co-occurring speech. A plethora of research in the last decade has shown that each of these modalities, although unique in certain ways, effectively utilizes movement and configuration to convey meaning and contribute to successful communication.Among an array of visual bodily cues that people resort to when conveying meaning, gestures stand out as a unique attribute of the human communication system. A wealth of research has shown that gestures (we use the term Bgesturesĥ ere to refer to movements of the hands and arms that are used to depict objects, ideas, events, and experiences; Kendon, 2004;McNeill, 1994) form an important aspect of communication. The study of gesture has opened a new window into human language,