This research examined the hypothesis that a conservative response bias in older persons interferes with the acquisition and mastery of cognitive skill. Twenty younger and 20 older Ss performed both consistent mapping and varied mapping versions of a memory search task. Half of the Ss in each group performed under speed stress instructions, whereas the remaining Ss performed under accuracy stress instructions. Older Ss exhibited less skilled performance than did younger Ss. A power function analysis attributed this to both age-related differences in the rate of associative learning and differences in asymptotic levels of performance. These results are at odds with A. D. Fisk and W. A. Roger's (1991) hypothesis that age-related differences in automatization do not occur in memory search tasks. Results are interpreted in terms of a learning vs. performance distinction.