The traditional approach to the study of selective attention in animal disc
rimination learning has been to ask if animals are capable of the central s
elective processing of stimuli, such that certain aspects of the discrimina
tive stimuli are partially or wholly ignored while their relationships to e
ach other, or other relevant stimuli, are processed. A notable characterist
ic of this research has been that procedures involve the acquisition of dis
criminations, and the issue of concern is whether learning is selectively d
etermined by the stimulus dimension defined by the discriminative stimuli.
Although there is support for this kind of selective attention, in many cas
es, simpler nonattentional accounts are sufficient to explain the results.
An alternative approach involves procedures more similar to those used in h
uman information-processing research. When selective attention is studied i
n humans, it generally involves the steady state performance of tasks for w
hich there is limited time allowed for stimulus input and a relatively larg
e amount of relevant information to be processed; thus, attention must be s
elective or divided. When this approach is applied to animals and alternati
ve accounts have been ruled out, stronger evidence for selective or divided
attention in animals has been found. Similar processes are thought to be i
nvolved when animals search more natural environments for targets. Finally,
an attempt is made to distinguish these top-down attentional processes fro
m more automatic preattentional processes that have been studied in humans
and other animals.