Facilitation and inhibition effects in visual selective attention processes of individuals with and without mental...

Adolescents with and without mental retardation participated in a visual selective attention task. They were required to identify one of two letters presented to them on the basis of color. We manipulated the relation between target and distractor letters on successive trials. A target letter could have been a target on the preceding trial, a distractor on the preceding trial, or not appear on the preceding trial. Subjects without mental retardation exhibited facilitation when the target was identical to the target on the preceding trial and inhibition when the target was a distractor on the preceding trial. Subjects with mental retardation also exhibited facilitation when the target was identical to the target on the preceding trial but not when it had been a distractor on the preceding trial. The inefficient suppression processes may result in performance deficits for individuals with mental retardation across a variety of tasks.