Time-of-day effects on objective and subjective short-term memory task performance

Area of Science:

• Cognitive Neuroscience
• Chronobiology
• Psychology

Background:

• Cognitive performance is influenced by time-of-day and individual chronotype, mediated by circadian and homeostatic processes.
• The Borbély two-process model describes these influences on sleep-wake regulation and cognitive function.
• Understanding these factors is crucial for optimizing task performance and well-being.

Purpose of the Study:

• To investigate the influence of circadian factors and sex on objective and subjective performance in a visual short-term memory task.
• To examine the synchrony effect (optimal performance time based on chronotype) on cognitive tasks requiring holistic processing.
• To explore novel behavioral data analysis patterns, including sex-specific effects and self-assessment scales.

Main Methods:

• Sixty-five healthy young adults (40 female) were categorized into morning and evening types based on chronotype questionnaires and PER3 gene polymorphism.
• Participants completed a modified Deese-Roediger-McDermott visual short-term memory task with abstract stimuli in both morning and evening sessions.
• Data analysis focused on objective measures (reaction times, accuracy) and subjective effort, exploring circadian and sex-related influences.

Main Results:

• Evening types demonstrated higher accuracy on the visual short-term memory task compared to morning types, irrespective of the testing time.
• A significant time-of-day effect was observed: reaction times were slower in the morning, while subjective effort was higher in the evening.
• A time-of-day by sex interaction revealed that men reported greater task demandingness in the evening sessions.

Conclusions:

• Chronotype significantly impacts visual short-term memory accuracy, with evening types performing better.
• Circadian rhythms influence cognitive performance, affecting both objective reaction times and subjective effort, with distinct patterns across the day.
• Sex moderates the subjective experience of cognitive task effort, suggesting potential sex-based differences in cognitive load perception influenced by time of day.