Spatial Attention Triggered by Eye Gaze: Evidence from a Microsaccade Study

Although human spatial attention is elicited toward gaze direction of another, it remains one unanswered question whether shift of spatial attention elicited by gaze direction of another is exogenous or endogenous orienting. The purpose of this study is to examine which type of attentional orienting is related to attentional shift elicited by gaze direction. To pursue this question, we conducted the attentional cuing paradigm and measured microsaccades during the task. In experiment 1, a facial stimulus was positioned in the center of the screen as a gaze cue whose direction showed the validity of the target presentation. We measured microsaccades after presentation of the cue. In the result, microsaccade direction was toward cue direction only in the 200 – 400ms time window after presentation of the cue. In experiment 2, we conducted the anti-saccade task for directionally separating exogenous and endogenous orienting, thus, gaze direction and cue direction were different unlike experiment 1. The result of experiment 2 agreed with the results of experiment 1, therefore, microsaccade direction was toward cue direction, not gaze direction. These results indicate that spatial attention elicited by gaze direction is endogenous orienting, not exogenous orienting.