The effect of time on delay discounting in younger and older adults

ObjectiveDelay discounting refers to the devaluation of future rewards as a function of time. Previous studies proposed the relationship between time perception and delay discounting in ageing, while there is a lack of evidence about the effect of different dimensions of time.MethodThis study explored the effect of delay length (1-day, 1-month, 6-month, 1-year, 5-year), time framing (delay, date) and time estimation (internal clock) on delay discounting in younger and older adults. Seventy younger adults and 57 older adults completed the delay discounting task and time estimation task.ResultsResults suggested the effect of age, but there were no effects of delay lengths and time framing on age differences in delay discounting. Meanwhile, internal clock predicted delay discounting in older adults, with higher discounting correlating with more internal clock variability.ConclusionAge differences in delay discounting may not be due to the effects of delay lengths and time framing, but rather to variations in the internal clock among older adults.