Age-Related Differences in Time Reproduction Reflect Attentional Control but not Stimulus Magnitude

Abstract

Abstract Research on age-related differences in time perception are mixed, with the strongest results indicating that age group differences are magnified based on the cognitive complexity of the specific task design. This raises the possibility that age-related differences in time perception may reflect downstream effects of ‘non-temporal’ factors such as stimulus magnitude, selective attention, and memory requirements. The current study explored this possibility with two experiments conducted on both younger and older adults that systematically varied stimulus magnitude and attentional demands. The first experiment was a focused–attention time reproduction task in which participants reproduced the temporal duration of a white rectangle with an embedded four-digit number. The stimulus magnitude varied from small (1000–3999) to medium (4000–6999) to large (7000–9999) digits. The second experiment was a divided-attention variant of the first experiment, where the participant either reported the temporal duration or recalled the number sequence embedded in the stimulus. Analyses indicated minimal age group differences under focused-attention conditions, but under divided-attention conditions there were age-related decreases in time estimates and temporal precision. Stimulus magnitude operated as predicted by the number–time association (NTA) effect, in which larger stimulus magnitudes induce longer duration estimates. Surprisingly, the NTA effect was evident similarly for both age groups and across both experiments. Exploratory analyses found evidence for age group equivalence in the positive influence of short-term memory on time reproduction, but age-related differences in the correlative link with cognitive processing speed. We conclude that age-related differences in our time reproduction task reflects attentional control factors but not stimulus magnitude.