Inhibitory control across the life span.

Findings from previous research suggest that inhibitory control improves during early childhood and declines during late adulthood. Very few researchers, however, have examined life-span changes in this ability in single studies. Within this life-span context, we investigated 1 type of inhibitory control--the ability to inhibit aprepotent response and generate an incompatible response--in individuals ranging from 6 to 82 years of age. Examination of raw reaction time data revealed a significantly larger inhibitory control effect for children and older adults than for young adults. Using proportional and z score transformations, we demonstrated that a processing speed explanation is sufficient to account for the differences in performance between children and young adults; this explanation, however, did not adequately explain the discrepancy between young and older adults. Taken together, these findings suggest that, above and beyond differences in processing speed, inhibitory control was less efficient in older adults. Our findings are consistent with the assertion that inhibitory control develops quite early and declines at the later end of the developmental spectrum.