Time-of-day effects on prospective memory

Area of Science:

• Cognitive Psychology
• Chronobiology
• Human Performance

Background:

• Cognitive functions exhibit daily fluctuations, known as time-of-day effects, with optimal performance varying across different cognitive domains.
• While time-of-day effects are established for declarative memory, their presence in prospective memory (memory for future intentions) remains under-investigated.

Purpose of the Study:

• To investigate time-of-day effects on prospective memory performance in young adults.
• To examine whether circadian preference (chronotype) or attentional resources modulate these effects.
• To assess performance across prospective memory tasks of varying complexity.

Main Methods:

• A pilot study (n=48) and a main experiment (n=39) compared prospective memory performance between morning (approx. 09:00) and evening (approx. 21:00) groups of young adults.
• Four prospective memory tasks were employed: Red Pencil Task, Syllable Detection Task (event-based), Dresden Breakfast Task (time- and event-based), and Color Task.
• Circadian preference and attentional resources were considered, with the latter assessed in one task.

Main Results:

• Significant time-of-day effects were found, with superior performance in the evening for the Red Pencil Task (p=.02), Syllable Detection Task (p<.048), and Dresden Breakfast Task (time-based: p=.026; event-based: p=.054).
• The Color Task did not show significant time-of-day effects (p=.14).
• Time-of-day effects were not modulated by circadian preference or attentional resources. Ongoing task performance did not significantly differ between morning and evening groups.

Conclusions:

• The study provides tentative evidence for time-of-day effects in prospective memory among young adults.
• Evening hours appear to be associated with enhanced prospective memory performance compared to morning hours.
• These effects seem independent of individual chronotype and the level of attentional resources required.