Carrasco, M. & McElree, B. (2001).
Covert attention accelerates the rate of visual information processing.
Proceedings of the National Academy of Sciences, 98: 5363-5367.
Whenever we open our eyes, we are confronted with an overwhelming amount
of visual information. Covert attention allows us to select visual information
at a cued location, without eye movements, and to grant such information
priority in processing. Covert attention can be voluntarily allocated,
to a given location according to goals, or involuntarily allocated, in
a reflexive man-ner, to a cue that appears suddenly in the visual field.
Covert attention improves discriminability in a wide variety of visual
tasks. An important unresolved issue is whether covert attention can also
speed the rate at which information is processed. To address this issue,
it is necessary to obtain conjoint measures of the effects of covert attention
on discriminability and rate of information processing. We used the response-signal
speed-accuracy tradeoff (SAT) procedure to derive measures of how cueing
a target location affects speed and accuracy in a visual search task.
Here, we show that covert attention not only improves discrim-inability
but also accelerates the rate of information processing.