ON THE CONTRIBUTION OF TOP-DOWN PREPARATION TO LEARNED CONTROL OVER SELECTION IN SINGLETON SEARCH

Abstract

Physically salient stimuli in the visual field tend to capture attention rapidly and automatically, leading to the perceived pop-out effect in visual search. There is much debate about if and how top-down preparatory processes influence visual attention when salient stimuli are present. Experience with a task involves learning at multiple levels of cognitive processing, and it can be difficult to distinguish these learning effects from the effect of a ‘one-shot’ act of top-down preparation on a given trial. That is, preparing to attend to a particular colour might influence search on a given trial, but that act of preparation may also become embedded in a memory representation that carries over to influence future search events. Moreover, such learning effects may accumulate with repeated experiences of preparing in a particular way. The goal of the present thesis was to examine specifically how preparation at one point in time affects pop-out search at a later point in time. To this end, I present the following empirical contributions: I introduce a novel method for studying preparation effects in search for a salient singleton target; I use this new method to explore the contribution of learning and memory to effects of preparation on singleton search, and outline a number of boundary conditions of this new method; and I distinguish between two components of the reported preparatory effects, one related to preparing to attend to a particular feature, and one related to preparing to ignore a particular feature. Together, these contributions highlight the contribution of top-down preparation to memory representations that guide attention in singleton search, and offer a novel method that researchers can use to ask unanswered questions about the roles of preparation and experience in singleton search.