抄録
Direction of gaze is an important, socially communicative signal between humans. When a gaze directed toward us exists in our visual field, our eyes are frequently and automatically captured by such a gaze. This implies that a gaze has salience and is processed in a parallel search strategy under the bottom-up attentional control. Previous studies have shown two different types of behavioral strategies in visual search, a parallel search strategy under the bottom-up attentional control and a serial search strategy under the top-down attentional control. In this study using visual search diagnostics, first, we investigated whether a gaze directed toward the subject can "pop out" or not (Exp.1). Second, we analyzed eye movements (saccades) during the visual search, to characterize differences in visual behavior between subjects with the "pop-out" effect for gazes and without the effect (Exp. 2). Finally, we investigated the effect of eye fixation (suppression of saccades), on visual search strategy which was taken by the subjects (Exp. 3). As the results show, (1) In about 40% of the subjects, a gaze toward them "popped out", indicating a parallel search strategy under the bottom-up attentional control (Exp.1). (2) Frequency of saccades occurred during visual search was smaller in the subjects with the "pop-out" effect for gazes than in those without the effect (Exp. 2). (3) Eye fixation biased the search strategy from top-down (serial) toward bottom-up (parallel) (Exp. 3). Taken together, the results indicate that in visual search for gazes, eye movement (saccade) is a critical constraint of search strategy taken by the subject. [J Physiol Sci. 2008;58 Suppl:S172]
