Abstract
A visual object inherently occupies a location, and a spatial location cannot be marked without some entity. Such an interwoven relationship between objects and locations has made the dissociation between object- and location-based attentional selection difficult. In a series of experiments, we examine whether the two kinds of selection can be modulated by different kinds of working memory tasks, and how stimulus configuration affects such modulation. A dual-task paradigm was used, in which the primary task was associated with a location or an object, and the secondary task involved either spatial or non-spatial working memory. Results from the first two sets of experiments revealed that location-based selection was affected by a secondary task that involved spatial working memory, whereas object-based selection was affected by a secondary task that involved non-spatial working memory. Changing the configuration of the stimuli influenced the modulation effects of the two kinds of working memory tasks accordingly. As spatial and non-spatial working memory modulate location- and object-based attention respectively, the double dissociation we have obtained in this study helps to disentangle object- and location-based attention, and provides a useful index for probing either one or both.
This study is supported by the National Science Council of Taiwan, NSC94-2752-H-002-008-PAE