Directors: Antonio M. Battro and Kurt W. Fischer
Program officer: María Lourdes Majdalani
Circadian rhythms in cognitive performance
Circadian rhythms in performance have been observed in many tasks, such as: sensory and motor tasks, reaction time, memory, reading comprehension, arithmetic calculations and time estimation. There are three basic cognitive processes, which can modulate performance: attention, working memory and executive functions. Circadian variations have been demonstrated for three components of attention (tonic alertness, phasic alertness and selective attention); for two storage components of working memory (phonological and visuospatial); and for several indicators of executive functions (inhibition, flexibility and response strategies). The levels of these cognitive processes are higher during daytime, increasing in the evening, with the lowest levels occurring at night and first hours of the morning. Circadian rhythms in these basic cognitive processes may produce changes in the performance of many tasks crucial for learning, productivity at work and the risk of accidents.