Social gaze cueing elicits facilitatory and inhibitory effects on movement execution when the model might act on an object

Social cues, such as eye gaze and pointing fingers, can increase the prioritization of specific locations for cognitive processing. A previous study using a manual reaching task showed that, although both gaze and pointing cues altered target prioritization (indexed via reaction times [RTs]), only pointing cues affected action execution (indexed via trajectory deviations). This discrepancy in the effects of gaze and pointing cues on action execution could be because the gaze cue was conveyed through a disembodied head; hence, the model lacked the potential for a body part (i.e., hands) to interact with the target. In the present study, the image of a male gaze model, whose gaze direction coincided with two potential target locations, was centrally presented. The model either had his arms and hands extended underneath the potential target locations, indicating the potential to act on the targets (Experiment 1) or had his arms crossed in front of his chest, indicating a lack of potential to act (Experiment 2). Participants reached to a target that followed a nonpredictive gaze cue at one of three stimulus onset asynchronies (SOA; 100, 350, or 850ms). RTs and reach trajectories of the movements to cued and uncued targets were analyzed. RTs showed a facilitation effect for both Experiments 1 and 2, whereas trajectory analysis revealed facilitatory and inhibitory effects, depending on the SOA, but only in Experiment 1. Results of this study confirmed that when the gaze model has the potential to interact with the cued target location, the model’s gaze would not only affect target prioritization, but also movement execution