Most of us naturally have a preference for either morning or evening – that is, we are either early birds or night owls – and we all know plenty of others who fit into one of these categories.
For night owls, doing anything early in the morning may be daunting, while they may work on creative projects, speed through emails and cross off numerous items on their to-do list after most others have already gone to bed. In contrast, early birds may go for a run, complete chores and accomplish a great deal before noon, but have little energy for any activities in the evenings.
Whether you are an early bird or a night owl, your internal clock plays a critical role in maximizing your mental performance, according to a recent Baycrest study. This effect is so strong that it can significantly impact academic performance for adolescent students and the results of brain health assessments for older adults.
“A person’s tendency to be a morning or an evening person is called their chronotype. Because of differences in chronotypes, we see significant differences in the time of day at which people are best at paying attention, learning, solving problems, making complex decisions and more," says Dr. Lynn Hasher, Senior Scientist at Baycrest’s Rotman Research Institute, the study's lead author and a key leader in this field of research.
An individual’s chronotype drives physiological and intellectual functioning throughout the day. Morning chronotypes rise and peak early in the day, while evening chronotypes have a later peak. Chronotype varies from person to person and also changes with age, from childhood to adolescence to old age. In general, adolescents are likely to be night owls, while older adults are more likely to be morning people.
In this scientific literature review, the researchers analyzed more than 150 previously published studies examining chronotypes and their effects on mental performance. Conducting the research with Dr. Hasher were Dr. Cynthia May (Professor of Psychology, College of Charleston) and Dr. Karl Healey (Associate Professor of Psychology, University of Michigan).
They found that a person’s chronotype has a strong effect on their ability to pay attention, learn, solve problems, make complex decisions and even behave in an ethical manner. This means that a morning person may have more difficulty learning new information later in the day, while an evening person may struggle to make decisions before noon.
Effects are strongest for those individuals who have a strong preference for morning or evening, and for tasks that require more analytical processing or the ability to ignore distracting information.
Chronotype appears to have the strongest impact for adolescents and older adults. Adolescents are generally strong evening chronotypes, but they tend to start school early in the morning, which may have a negative effect on their academic performance. In addition, because the majority of older adults show a strong biological preference for the morning, they tend to perform much worse on cognitive tests later in the day. This could result in a brain health assessment indicating cognitive decline for an individual who is in fact cognitively healthy, which could in turn lead to unnecessary stress for that person and compromise their quality of life.
Overall, these results indicate the importance of recognizing and accounting for chronotype in a wide variety of settings, from academic and medical situations to social settings and more.
"By better understanding and acknowledging chronotypes, we can help individuals optimize their mental performance and live their best possible lives, no matter their age,” says Dr. Hasher.
This research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), the National Science Foundation and the National Institute on Aging.