Process-specific slowing with advancing age: Evidence derived from the analysis of sequential effects.

Examined the generalized slowing hypothesis on the mechanisms underlying sequential effects in serial two-choice reaction time tasks with 21 19-25 yrs olds and 18 Ss aged 60-75 yrs. For young adults, sequential effects of conditions with a high and a low stimulus presentation rate respectively pointed to an automatic and an expectancy mechanism. Older adults' low presentation rate data corroborated the general slowing hypothesis for expectancy, whereas the high presentation rate results did not. The observation of a differential influence of age on the automatic and the expectancy mechanism poses a problem for notions assuming that higher level processes are more vulnerable to advancing age than lower level processes. (PsycINFO Database Record (c) 2002 APA, all rights reserved)