Age differences in inhibition: Possible causes and consequences

The relations among age, inhibition, perceptual speed, susceptibility to interference, and working memory were examined in a sample of 301 adults age 20 to 90. Younger adults were found to have more efficient inhibitory mechanisms than were older adults. Significant inhibition, however, was found in all age groups, including the older age group. Older adults were also found to be more susceptible to interference from irrelevant information. There was a small negative relation between interference and inhibition, suggesting that participants with the most efficient inhibitory functioning may be the least susceptible to interference. Perceptual speed, an index of processing efficiency, was found to mediate nearly all of the age-related variance in inhibition and interference. Interference, but not inhibition, was found to mediate some of the age-related variance in working memory.