Abstract
Visual search for negative target faces among neutral distractor faces is more efficient than search for positive faces. The present experiments introduced a new search technique to dissociate between contributions of pre-attentive guidance and post-attentive template matching processes to this difference in search efficiency. In Experiment 1, participants searched for negative or positive target faces presented among varying numbers of neutral faces. Search was performed under standard viewing conditions (Exp 1a) or a new restricted viewing condition where items were occluded by black placeholders, and a given item was revealed only when a participant moved the mouse pointer over the black square (Exp 1b). Search slopes for identifying negative faces were shallower than slopes for positive faces, indicating more efficient search, but only in the standard search task. When guidance by unattended items was prevented in the new task, search was much less efficient and search slopes did not differ for the positive and negative target faces. Experiment 2 (easy pop-out search) and Experiment 3 (difficult conjunction search) yielded considerably flatter and steeper slopes, respectively, showing that the lack of a slope difference in Experiment 1b was not due to floor- or ceiling effects associated with the unique motor demands of the new method. Together, these findings support the notion that emotional information is processed pre-attentively and influences the allocation of focal attention. Furthermore, they demonstrate the utility of our new search technique for selectively investigating various influences on visual search, such as pre-attentive guidance, template matching, and perceptual grouping.
The research was supported by NSERC