"Cued at First Sight": Evaluating the Influence of Depth on Gaze Cues

When an individual provides a social cue, such as pointing or looking towards the left or right, an observer’s attention can involuntarily be drawn towards the cued location. Evidence for this social cueing effect comes from observers’ shorter reaction times (RTs) for targets at cued locations than at non-cued locations. However, it remains unknown whether observers are also sensitive to the depth of such social cues (in addition to the side of space indicated). Spatial depth refers to whether an area is relatively “near” or “far” from the observer. PURPOSE: The purpose of the current study was to determine whether observers are sensitive to the spatial depth of gaze cues. We hypothesized that if the social gaze cueing system is sensitive to depth, then RTs for targets in the same depth plane as the gaze cue (e.g., gaze near/target near) will be shorter than for targets in a different depth plane as the gaze cue (e.g., gaze near/target far). However, if the social cueing system is not sensitive to depth, then RTs will not differ for targets across the different depths. METHODS: Participants (n=15) performed a computer-based RT task, where they responded with the left or right hand for a blue or red stimulus, respectively. In each trial, an avatar provided a gaze cue by rotating their head to randomly stop to face one of four possible target locations: near-left, near-right, far-left, and far-right. After a random stimulus onset asynchrony (SOA) of 100 or 1000 ms, a blue or red target stimulus appeared at one of the four possible locations. Participants responded by pressing a keyboard key that corresponded to the target color as quickly and accurately as possible. Thus, the gaze cue was irrelevant to participants’ response to the colored target, but the gaze cue may still influence their response. RESULTS: A repeated measures ANOVA revealed that RTs were shorter to targets in the same depth as the gaze cue, compared to targets in a different depth, but only at the 100 ms SOA, F(1,14)=4.78, p<0.05. CONCLUSION: The results support the conclusion that the social gaze cueing system is sensitive to depth, evidenced by the shorter RTs for targets at the gazed-at depth. These findings provide novel insight into the factors that influence the gaze cueing system and contribute to our understanding of human perception.