Abstract
Abstract: With each saccade, the retinal projection of the world is displaced. Despite this displacement, we perceive the world as being stable. Stable perception of visual space requires that points in the new image are associated with corresponding points in the previous image. Most research has focussed on how visual stability of a saccade target object is achieved. However, the present study investigates transsaccadic memory for location information of non-saccade target objects (bystanders). In a first experiment, subjects fixated a central red source-dot, surrounded by a random-dot pattern consisting of 1 to 6 black bystander dots, and one red saccade-target dot. During a saccade to the saccade-target dot, the position of one of the bystanders could either change slightly or remain the same. Subjects reported whether the dot-pattern was identical to or differed from the preview. The results showed a clear capacity-limitation in the number of location-indexes that could be maintained across a saccade. In a second experiment the pre-saccadic display was identical to the first experiment, but the post-saccadic display contained only the source, the saccade-target, and one bystander. Again the bystander was either shifted slightly or remained in place across the saccade, and subjects reported whether its position had changed or not. This allowed us to assess the importance of saccade-source, saccade-target, and bystander configurations in coding the location of a specific bystander. The implications of these and other results for transsaccadic memory of object locations are discussed in terms of capacity, representational format, and existing theories on visual stability and transsaccadic memory.
This research is supported by Concerted Research Effort convention.