Abstract
Conscious, visual perception depends on information stored in visual working memory (VWM). VWM, however, suffers from capacity limits and only about four objects can be represented at the same time. It is often suggested that our limited selective attention is responsible for this. Recent research has shown the existence of a more vulnerable, but high capacity form of VWM ( > 15 objects). This high capacity is evident whenever an attention-guiding cue is presented during stimulus maintenance; then, almost all objects that are shown can be retrieved and reported about. This suggests that not visual memory itself, but its report depends on attention.
To test that hypothesis, we present a study in which we distract participants' attention during stimulus encoding. Visual memory was measured using a Change Detection task. During this task, attention was manipulated in three different ways. In one condition, uncertainty about stimulus presentation was created. In a second condition, participants performed an N-back task during stimulus encoding. In a third condition, an Attentional Blink paradigm was used to decrease attention for the stimulus array. Preliminary results show that engaging attention impairs performance on a classical Change Detection task, but memory is unaffected when a guiding cue is presented during stimulus maintenance. These results suggest that the brain stores many objects independent of attention, and that attention is only necessary to report or otherwise cognitively manipulate these items.