Abstract: As the most prominent part in the face, eyes are usually considered as one of the most important information source. Former studies have shown that people's attention tends to shift to certain locations by others' eyes gazing. The gaze-cuing effect (GCE) is that when the eyes in the central face are gazing at the same direction of the targets which would be presented at periphery could accelerate the detection of the targets.
The present study investigated the impact of different emotional faces which are displayed unconsciously on the gaze-cuing effect. A happy, neutral, or fearful cue face with its eyes gazing at left side or right side was presented unconsciously in the center of the computer screen, followed by a capital letter F as target at the gazed (cued) location or the opposite location (uncued) randomly. Participants were asked to accomplish several location judging tasks, which were that subjects should make localization responses to the capital letter F that was appeared randomly on the left side or the right side of the screen as accurately and quickly as they can. Using pseudorandom method to balance the sequence effect and control the Simon Effect by ruling the response keys. Results are (1) RTs were significantly longer and accuracies was significantly smaller in the un-cued condition than the cued condition. (2) In the cued condition, RTs were significantly shorter in the fearful face condition than those in the happy and neutral faces condition. On the contrary, in the un-cued condition, RTs of fearful face condition were significantly longer than those in the happy and neutral faces condition. Results above showed that the gaze-cuing effect (GCE) was significant and was modulated by the emotional faces (happy, neutral, or fearful) presented in the center of the screen before when the cues were presented subliminally. In the cued condition, fearful emotion could accelerate the shifting of attention and lead to the faster detection of targets. However, in the un-cued condition, this way of acceleration could make people shift their attention to the opposite side so that decelerating the detection process of the targets displayed. Take the difference between valid conditions and invalid conditions in the reaction times (gaze cue effect size) as the independent variable, the analysis of result showed that the gaze-cueing effect size in the fearful face condition was larger than the happy and neutral face, while the difference between happy and neutral emotion was not significant.
All the results above indicated that emotional stimulus which are displayed subliminally could get rid of the suppression of the Top-Down attention mechanism, motivating people's primary biological reaction. The gaze-cuing effect (GCE) can be modulated by emotional faces with biological importance that were presented unconsciously. The subliminally presented gazing cue was processed automatically and resulted in attention bias, especially the fearful face cue.

Key words: subliminally, gaze direction, facial expression, gaze-cueing effect, attentional bias