The Effects of Aging on Performance on Two Choice RT Tasks
Roger Ratcliff (Psychology Department, The Ohio State University)
(May 2, 2006 4:30 PM - 5:30 PM)
In recent studies, we have applied a diffusion model to examine differences in processing between college students and older adults. The results show that in several paradigms, namely signal detection, brightness discrimination, recognition memory, and lexical decision, the rate of accumulation of evidence in the decision process is not significantly different for the two groups. Longer response times for the older adults come from more conservative decision criteria and from a small increase in the nondecision components of processing. In contrast, in letter discrimination, the older adults' longer response times come from a reduced rate of accumulation of evidence, as well as more conservative decision criteria and a small increase in the nondecision components of processing. In this talk, we review these results, present data from the same group of subjects tested on four of these tasks, and we apply other sequential sampling models to the data from the five paradigms to determine whether the results obtained using the diffusion model are specific to that model or general across the class of models. I will also work through the models and show how they account for correct and error RT distributions and accuracy and how parameters are associated with different experimental effects.