Cognitive performance can fluctuate by 15 points throughout the day and return to baseline.
the verdict
INSUFFICIENT LEANING
refutedsupported
the weight of evidence
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Retrieved literature confirms that cognitive performance exhibits diurnal variations and fluctuations across different times of day, but no available source establishes the specific 15-point magnitude asserted by the claim.
Much research assessing time of day (ToD) effects on cognitive performance typically assign participants to a morning or evening condition. However, this may not accurately reflect variations in peak arousal as the best ToD of taking part in cognitive tasks may fluctuate throughout the day. Sleep and caffeine consumption may also interact with the ToD of testing and could potentially affect cognitive test scores. The aim of this study was to understand differences in cognitive performance when participants are allowed to choose their preferred optimal and non-optimal ToD of taking part and explore interaction effects of the ToD of testing with sleep and caffeine on a range of memory tasks. Twenty-seven cognitively-healthy young adults completed a sleep, ToD, and caffeine questionnaire followed by a series of memory tasks online, at two separate time points (once at their chosen optimal ToD and once at their chosen non-optimal ToD) within a 24-hour period. Findings revealed that participants performed significantly better at their chosen optimal ToD compared to their chosen non-optimal ToD on all the memory tasks. The findings have important implications for the need to consider ones subjective ToD preferences when taking part in a range of memory tasks in various contexts.
are known to show homeostatic and circadian fluctuations in alertness and selective and sustained attention. They improve during the day, with higher levels in the afternoon and evening hours. Circadian rhythm itself is associated during the night and in the early morning with an increased risk of errors, though this can depend on chronotype [ 12 ]. Interestingly, a time-of-day effect is important also for prospective memory, irrespective of chronotype [ 12 , 13 ]. The strength of the relation between time of the day and cognitive performance increaseswith age. The level of cognitive functioning in older adults is significantly worse at a non- optimal time of day [ 14 ]. EFFECT OF CHRONOTYPE ON COGNITIVE FUNCTIONING
The relationship between chronotype and cognition is influenced by many factors, such as age, task difficulty, and duration of the task, duration the period of wakefulness, testing method used, and length, quality, and degree of sleep inertia, which is defined as a physiological process that occurs immediately after awakening and is characterized by a reduced level of activation and increased disorientation. The basic rest-activity cycle with a 90-minute fluctuation in alertness is also relevant to cognitive performance [ 2 , 15 ].
The latest research indicate that chronotype is strongly related to cognitive functioning, with better performance at the individual’s preferred time of the day [ 16 ]. People with an evening chronotype cope better with the increasing need for sleep, which allows them to maintain cognitive performance in the evening, whereas in people with a morning chronotype it deteriorates compared to their morning capabilities [ 14 ]. Lezak et al . [ 17 ] categorize cognitive functioning in four basic groups: receptive functions, memory and learning, thinking, and expressive functions. They also distinguish the mental activity variables responsible for maintaining the readiness of the cognitive system. Within each of these domains, more el
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