Semantic activation during memory encoding across the adult life span.

The hypothesis that automatic processes do not change during aging was investigated using Warren's (1972) modification of the Stroop procedure. The subjects were 14 adults in each of three age groups: young (20 to 39), middle (40 to 59), and old (60 to 79). On each trial, subjects held three category members in memory while they named the ink color in which a base item was printed. For all three age groups, color naming latencies were longer when the base item was from the same category as the memory list items. According to network theories of long-term memory, these findings suggest that, throughout adulthood, holding words in working memory results in activation of the memory nodes corresponding to the words themselves, and also in activation spreading to semantically related nodes. The results are consistent with the hypothesis that acquired automatic processes do not deteriorate with aging.