Motion aftereffects from viewing another's gaze are restricted to the line of sight

Recent work has shown that brief exposure to static images depicting an agent actively gazing at an object produces a motion aftereffect in the direction of the gaze. Such findings suggest that encoding of an implied agent-to-object motion takes place. Here, we adapted a previously used random dot motion paradigm, quantifying changes in perceptual decision thresholds for detecting left vs. right motion, to include probes in different spatial locations following the agent-and-object image. As with motion aftereffects from real motion, the aftereffects following exposure to the image were constrained to a limited portion of the visual field, specifically on and immediately above the line of sight of the agent in the image. The effect disappeared in control experiments featuring a blindfolded agent. These findings strongly support the notion that our brains encode others' attentive gaze as an implied agent-to-object motion, and for the first time reveal the spatial extension of this internally generated motion signal.