A diffusion model analysis of the effects of aging on recognition memory

The effects of aging on response time were examined in a recognition memory experiment with young, college age subjects and older, 60–75 year old subjects. The older subjects were slower than the young subjects but almost as accurate. Ratcliff s (1978) diffusion model was fit to the data and it provided a good account of response times, their distributions, and accuracy values. The fits showed a 100ms slowing of the nondecision components of response time for older subjects relative to young subjects, and roughly equal response criteria settings with accuracy instructions but more conservative settings for the older subjects with speed instructions. In the diffusion model, the decision process is driven by the rate of accumulation of evidence from the stimulus. We found that the rate of accumulation for older subjects was a non-significant 7% lower than the rate for young subjects, indicating that the output from recognition memory entering the decision process was not significantly worse for the older subjects. The results are compared to those obtained from letter discrimination, brightness discrimination, and signal detection-like tasks. 2003 Elsevier Inc. All rights reserved.