Aging, optimal testing times, and negative priming

The effects of time-of-day preferences an selective attention were tested in 2 experiments after normative work with 975 younger adults and 143 older adults verified C. P. May, L. Hasher, and E. R. Stoltzfus's (1993) finding that most older adults prefer the morning, whereas younger adults prefer activities later in the day. In Experiment 1, the cognitive effects of testing at preferred or nonpreferred times of day were examined in negative priming and related paradigms because (a) older adults typically have not shown negative priming and (b) previous research has not taken preference and testing times into account. In contrast to those tested at nonpreferred times, both younger and older groups tested at their preferred times showed negative priming. Age or testing optimality also affected other priming tasks. The central results were replicated in Experiment 2, which tested younger and older adults at their preferred times of the middle of the day.