Attention is fast but volition is slow

Abstract

How swiftly can the object of your attention be changed? Consider two ways to deploy attention: it can be commanded from place to place by a deliberate act of will, or it can run freely without specific instruction. Here we use a visual search task to show that deliberate movement of attention is significantly slower because of an internal limit on the speed of volitional commands. Extensive research on visual search tasks such as finding the letter F among other letters has revealed that stimuli of this sort can be searched at a rate equivalent to one letter every 25-50 ms. The order of search, even of eye movements, is influenced by stimulus salience and eccentricity, but is otherwise random through the set of salient loci. Why is there sparse evidence for systematic scanning of search displays? We argue that searching is free-running ('anarchic') because commanded, ordered deployment of attention is so much slower than anarchic deployment that it is faster overall to make many anarchic attentional deployments than fewer orderly ones.