Sources of interference from irrelevant information: a developmental study.

The present study investigated the mechanisms underlying reductions in the susceptibility to interference from irrelevant information that are evident in the developing child. In the first experiment, where the task was to focus on one stimulus dimension and to ignore a second dimension, variations in the degree of spatial integration in multidimensional stimulus configurations did not influence interference effects. Developmental trends in selective attention could not be attributed to age changes in the accessibility of dimensional structure. The second experiment, where the task was to focus on a central arrow stimulus and to ignore flanking arrows, allowed further examination of the mechanisms involved in developmental changes in interference effects. The primary source of the developmental decrease in interference from irrelevant information was found to be in the rate at which the output of perceptual analysis is coupled to the preparation and execution of a motor response, rather than in perceptual filtering or in response preparation. The combined results suggest that age changes in selective attention are mediated to an important extent by changes in the speed and efficiency of stimulus-response translation processes. These findings are discussed in terms of developmental theories of interference control.