Eye movements as Markers of socio-cognitive and emotional engagement in gesture observation and imitation

Aims This study investigated fixation patterns within two areas of interest—face and hand—during the observation and imitation of gestures. It examined how gesture meaning (intransitive, pantomime, and meaningless) and spatial direction (towards or away from the body) influenced visual attention. Method 23 healthy participants watched 60 video clips (4s each) depicting three types of gestures: intransitive (e.g., waving), pantomime (i.e., miming an object's use), and meaningless (i.e., hand or finger configurations with no intrinsic meaning). Gestures were directed either toward the body (TB) or away from the body (AB). The experiment included two conditions: passive observation and imitation, with the observation phase always presented first to dissociate perceptual from motor components. Eye movements were recorded using an eye tracker allowing free head movements. For each stimulus, the total number of fixations and cumulative fixation duration within each area of interest were extracted, and the average fixation duration was calculated. Results A 2(condition)×3(gesture)×2(direction)×2(area of interest) ANOVA revealed significant main effects. Fixation duration was longer during observation than imitation (p = .002, ηp² = 0.35). Gesture type also influenced fixation duration (p < .001, ηp² = 0.50), with intransitive gestures eliciting longer fixations than pantomime and meaningless gestures. Direction significantly affected fixation patterns (p = .022, ηp² = 0.21), with TB gestures leading to longer fixations than AB gestures. The area of interest also played a role, as faces attracted longer fixations than hands (p = .019, ηp² = 0.22). A significant area of interest×gesture interaction was found (p < .001, ηp² = 0.37). For hand fixations, intransitive gestures elicited longer fixation durations than meaningless and pantomime gestures (all p < .001). Similarly, for face fixations, intransitive gestures led to longer fixations than meaningless gestures (p < .001). Discussion Fixation duration varied as a function of gesture type, direction, and area of interest, reflecting distinct cognitive and socio-emotional processing mechanisms. Intransitive gestures, being inherently social, elicited longer fixations, particularly when directed toward the body, suggesting increased socio-cognitive engagement(1). The longer fixations on faces highlight their importance in extracting contextual information. The extended fixation duration during observation compared to imitation suggests that passive viewing engages visual exploration for meaning extraction, a process less required during imitation. Conclusions These findings emphasize the role of eye movements in action perception and organization(2) and provide insights into the visuomotor and socio-cognitive underpinnings of action perception and their potential disruptions in apraxic patients.