Spatial working memory load impairs signal enhancement, but not attentional orienting

The present study examined the effect of spatial working memory load on the attentional cuing effect. It is well-known that spatial working memory and spatial attention functionally overlap or share a common resource. Given this functional overlapping, it is possible that spatial working memory would also interact with the attentional cuing effect. Considering the distinction between channel selection and channel enhancement by attention (Prinzmetal, McCool, & Park, 2005), we expected that the interaction between spatial working memory and the cuing effect would differ with attentional processing type. Two experiments conducted with the spatial cuing paradigm showed that the magnitude of the cuing effect as measured by reaction time, reflecting channel selection, was uninfluenced by spatial working memory load. In contrast, spatial working memory load reduced the cuing effect as measured by accuracy, reflecting channel enhancement. These results suggest that spatial working memory load impairs signal enhancement by attention and does not influence attentional orienting per se. The interaction between spatial working memory and visual perception is also discussed.