SIMILARITY DETERMINES THE ATTENTIONAL BLINK

When participants are required to respond to a target letter imbedded in a stream of rapid serially presented letters, perception of a 2nd t arget letter is impaired if the interval between the 2 targets is less than about 450 ms. This attentionally based posttarget suppression in visual processing, referred to as the attentional blink (AB), is not found when there is a brief pause in the stream immediately after the Ist target. To investigate the importance of posttarget stimulation in AB production, the categorical, featural, and spatial similarity of t he immediate posttarget item to other items in the stream was manipula ted. Although featural and spatial dissimilarity produced significant attenuation of the AB effect, categorical dissimilarity did not. Signi ficant AB effects were found in all conditions, suggesting that the pr esentation of any patterned stimulus in close temporal proximity to th e target provokes the AB.