A study of adaptive behavior: eects of age and irrelevant information on the ability to inhibit one's actions

In the study of adaptive behavior, the stop-signal paradigm provides a measure of the ef®ciency of response suppression that lends itself to examining the ability to inhibit one's actions, and two complementary types of factors that may in ̄uence that ability. Based on neurobiological considerations, age-related individual di€erences were hypothesized to be such a factor. In agreement with the the cognitive-neuroscience literature, which emphasizes the relatively late maturation and early senescence of the (pre)frontal brain structures that are crucial for inhibitory control, results are reported of a study demonstrating that response inhibition in the stop task is subject to an unequivocal age trend during child development. Stop task performance was hypothesized to be in ̄uenced further by the e€ects of irrelevant information. In a concurrent reaction time task, distractor stimuli may induce activation of an incorrect response. The subsequent inhibition of this incorrect response activation may interact with the suppression of responses in the stop task, if both are engaged simultaneously. Indeed, in a study designed to examine this prediction, the operation of response inhibition in the primary-task and stop processes a€ected one another negatively when distractors were associated with the incorrect response. Ó 1999 Elsevier Science B.V. All rights reserved. PsycINFO classi®cation: 2260; 2330; 2340; 2820