Spatial Working Memory And Saccade Inhibition Of Return

A response to a visual target presented at a pre-cued spatial location is facilitated if the target is presented shortly after the cue and inhibited when the cue target onset asynchrony approaches a few hundred ms (about 300ms). The latter impairment at the recently attended location was first demonstrated by Posner and Cohen (1984) and has come to be known as inhibition of return (IOR).A key issue in the investigation of IOR effect is the function of the inhibition of return. Klein et al. (1988, 2000) and Posner et al. (1984) suggested that inhibition of return could act as memory for already attended locations. IOR might therefore increase the chance to attend or direct a saccade to a new location, this mechanism has referred as the foraging facilitator hypothesis. Hooge et al (2005), however, suggested that the inhibition of return is an intrinsic aspect of shifting attention and/or gaze direction rather than served as a foraging facilitator.In the current study, we examined the function of the IOR directly by introducing Spatial working memory load. The results of experiment 2A-2C showed that the saccade IOR is independent of the spatial working memory load although overall saccade reaction time tending lesser in the presence of the WM task. These results suggest that IOR, at least saccade IOR, is not serving as a foraging facilitator. These results also provide some evidence for the dissociation between the attentional and motor components of IOR.