There are voluntary (endogenous) and reflexive (exogenous) mechanisms of guiding selective attention.⇒
Stimuli which are non-predictive in a task—like localized stimuli in one modality which are non-predictive of the position of the target in another modality—can enhance performance in valid instances of that task—like detecting targets which by coincidence are where the non-predictive stimulus was.
This demonstrates the existence of exogenous attention.⇒
Bertelson et al. did not find a shift of sound source localization due to manipulated endogenous visual spatial attention—localization was shifted only due to (the salience of) light flashes which would induce (automatic, mandatory) exogenous attention.⇒
A localized visual stimulus can shorten the response to a target stimulus if it appears near and shortly after the first stimulus.
It can lengthen the response time if the target stimulus appears somewhere else or too late.⇒
A localized visual stimulus can lengthen the response time to a target if the target stimulus appears somewhere too late after the first stimulus.
This is called `inhibition of return'.⇒