Abstract
Do items in working memory guide attention to memory-matching items in the visual field? According to the Biased Competition Model, visual search is completed by items in working memory biasing attention toward similar items in the visual field (Desimone & Duncan, 1995). This leads to the prediction that items in working memory guide search, even if there is no explicit search goal for the item. Involuntary working memory guidance of attention has received empirical support (for a review, see Soto et al., 2008), but contradictory evidence has emerged suggesting that guidance is not involuntary (Woodman & Luck, 2007). In this work, we attempted to determine if guidance is dependent on the memory matching item's relevance for the search task. If working memory guides attention toward similar objects involuntarily, changes in task demands- such as increasing probability of memory match as target- should not influence attention being directed to the memory match. We manipulated the frequency of the memory matching information being the search target in two conditions; 25% memory color as target, and 50% memory color as target. To measure attention being directed to the memory matching distractor, we compared reaction times (RTs) when the memory match is the target to reaction times when it is not. We found a RT benefit when the memory color was the target for both 25% match and 50% match conditions and a larger benefit for the 50% than 25% condition. These effects show that RT guidance effects can be altered by the likelihood of a memory match being important for search. This finding suggests that guidance effects are not completely involuntary — guidance can be influenced by task demands.