Dn. Johnson et S. Yantis, ALLOCATING VISUAL-ATTENTION - TESTS OF A 2-PROCESS MODEL, Journal of experimental psychology. Human perception and performance, 21(6), 1995, pp. 1376-1390
Observers require less time to identify a visual target when its locat
ion is cued in advance than when it is not cued, and the magnitude of
the improvement depends on the validity of the cue. According to J. Jo
nides's (1983) 2-process model, there exist 2 possible modes of attent
ional readiness: a focused-attention mode and a diffuse-attention mode
. Observers are assumed to enter the focused-attention mode on a propo
rtion of trials that matches the validity of the cue and to enter the
diffuse-attention mode on the remaining trials. The present experiment
tested and rejected the response time mixture prediction of the 2-pro
cess model. An instance of the class of 1-process models in which perc
eptual objects are sampled in parallel according to, the validity of t
he cue was evaluated. A stochastic simulation of the model yielded res
ults that paralleled those of the experiment.