Can deployment of attention be strategically controlled?

Department of Psychology, University of Novi Sad, Serbia The main goal of the experiment was to test whether deployment of attention could be strategically controlled. Subjects viewed five-letter arrays. Each array included a letter unique in shape (i.e. target). One of the letters in each array (target or non-target) also differed from other letters in color or in position in relation to the array. That letter will be referred to as a feature singleton. The probability ratio of the feature singleton being the target or a non-target letter was varied throughout three experiments. The ratios were (1) 0.5 (target) : 0.5 (non-target); (2) 0.2 (target) : 0.8 (non-target); (3) 0.8 (target) : 0.2 (non-target). Subjects in all three experimental conditions deployed serial processes, but failed to maintain complete intentional control during the course of the search.