Abstract
We recently demonstrated that visual information rendered invisible through interocular suppression could still guide the distribution of spatial attention (Jiang et al., VSS 2005). In the current study, we further investigated whether invisible information could influence the direction of saccadic eye movements. Two images, one intact and one scrambled, were presented to the left and the right side of a fixation point. However, this pair of images was only presented to the observers' non-dominant eye while high contrast dynamic random Mondrian patterns were presented to their dominant eye at corresponding retinal locations. Identical Mondrian patterns were presented on both sides of the fixation point and remained dominant throughout each trial so that observers were completely unaware of which side of the fixation point received the intact test image. Images with different levels of valence (e.g., erotic images, emotional and neutral faces) were used as test stimuli. We recorded the position and movement of the suppressed eye while observers viewed the dichoptic visual stimuli. Even though observers were not aware of which side the intact image was located, their eyes were more likely to move towards the side containing the intact image. The influence on eye movements was stronger for erotic pictures than for emotional faces, with neutral faces generating the weakest effect. Apparently, pictures with high arousal value, even when invisible, were still effective in attracting saccadic eye movements towards them. The results suggest that eye movements, as well as visual spatial attention, are influenced by invisible information.
This research was supported by an award from the James S. McDonnell foundation and a National Institutes of Health Grant R01 EY015261-01.