Visual search tasks: slowing of strategic and nonstrategic processes in the nonlexical domain.

Some investigators have argued that aging affects the slowing of processes in nonlexical tasks more than it does the slowing of processes in lexical tasks, but that within task domains, the slowing is identical. Other investigators have argued that even within nonlexical tasks there is differential slowing such that aging affects processing speed more in (nonlexical) coordinative tasks than it does in (nonlexical) sequential tasks. Perhaps, more finely still, there is a differential slowing in coordinative nonlexical tasks. Toward this end, latent models of general and process-specific slowing in coordinative nonlexical tasks were formulated for older adults. A visual search task was then used to test the two types of models. It was found that a latent model of process-specific slowing explained significantly more of the variability than a latent model of general slowing, indicating that there is a differential slowing of processes among coordinative tasks within the nonlexical domain. It was also discovered that the coordinative process most greatly affected was that of deciding to terminate the search when no target was present in the display, indicating together with other studies a possible difference in the slowing of strategic processes among both coordinative and sequential tasks within the nonlexical domain, but no difference in the slowing of nonstrategic processes.