Summary: H
ow 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 delib-
erate act of will, or it can run freely without
specific instruction. Here we use a visual
search task to show that deliberate move-
ment 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 in Fig. 1a has
revealed that stimuli of this sort can be
searched at a rate equivalent to one letter
every 25­50 ms (ref. 1). The order of search,
even of eye movements, is influenced by
stimulus salience and eccentricity, but is
otherwise random through the set of salient
loci2

Source: Alvarez, George A. - Department of Psychology, Harvard University
Harvard University, Visual Attention Lab

Collections: Biology and Medicine