Summary: Contrary to previous findings, a new study reports those who rise early tend to have superior verbal skills compared to night owls.
Source: University of Ottawa
Night owls may be looking forward to falling back into autumn standard time but a new study from the University of Ottawa has found Daylight Saving Time may also suit morning types just fine.
Research from Dr. Stuart Fogel, a cognitive neuroscientist, professor at the University of Ottawa’s School of Psychology, and researcher at the Royal’s Institute for Mental Health Research, is shedding light into how the impact of a person’s daily rhythm and activity levels during both wake and sleep relate to human intelligence. Contrary to the adage “the early bird gets the worm,” previous work suggests that evening types, or “owls,” have superior verbal intelligence.
Yet, “once you account for key factors including bedtime and age, we found the opposite to be true, that morning types tend to have superior verbal ability,” says Stuart Fogel, Director of the University of Ottawa Sleep Research Laboratory. “This outcome was surprising to us and signals this is much more complicated that anyone thought before.”
Fogel’s team identified individual’s chronotype – their evening or morning tendencies – by monitoring biological rhythms and daily preferences. A person’s chronotype is related to when in the day they prefer to do demanding things, from intellectual pursuits to exercise.
Young individuals are typically “evening types” while older individuals and those more regularly entrenched in their daily/nightly activities are likely “morning types”. The juxtaposition here is that morning is critical for young people, especially school aged children and adolescents, who have their schedules set by their morning-type parents and their routines. This might be doing youngsters a disservice.
“A lot of school start times are not determined by our chronotypes but by parents and work-schedules, so school-aged kids pay the price of that because they are evening types forced to work on a morning type schedule,” says Fogel.
“For example, math and science classes are normally scheduled early in the day because whatever morning tendencies they have will serve them well. But the AM is not when they are at their best due to their evening type tendencies. Ultimately, they are disadvantaged because the type of schedule imposed on them is basically fighting against their biological clock every day.”
The study enlisted volunteers from a wide age range, who were rigorously screened to rule out sleep disorders and other confounding factors. They outfitted volunteers with a monitoring device to measure activity levels.
Establishing the strength of a person’s rhythm, which drives intelligence, is key to understanding the results of this nuanced study, says Fogel, with a person’s age and actual bedtime proving important factors.
“Our brain really craves regularity and for us to be optimal in our own rhythms is to stick to that schedule and not be constantly trying to catch up,” adds Fogel.
About this circadian rhythm and verbal intelligence research news
Does the early bird really get the worm? How chronotype relates to human intelligence
Chronotype impacts our state at a given time of day, however, chronotype is also heritable, trait-like, and varies systematically as a function of age and sex. However, only a handful of studies support a relationship between chronotype and trait-like cognitive abilities (i.e., intelligence), and the evidence is sparse and inconsistent between studies. Typically, studies have: (1) focused on limited subjective measures of chronotype, (2) focused on young adults only, and (3) have not considered sex differences. Here, using a combination of cognitive aptitude and ability testing, subjective chronotype, and objective actigraphy, we aimed to explore the relationship between trait-like cognitive abilities and chronotype.
Participants (N = 61; 44 females; age = 35.30 ± 18.04 years) completed the Horne-Ostberg Morningness-Eveningness Questionnaire (MEQ) to determine subjective chronotype and wore an activity monitor for 10 days to objectively assess bedtime, rise-time, total sleep time, inter-daily stability, intra-daily variability, and relative amplitude. Cognitive ability (e.g., Verbal, Reasoning and Short-Term Memory) testing took place at the completion of the study.
Higher MEQ scores (i.e., more morning) were associated with higher inter-daily stability scores. Superior verbal abilities were associated with later bedtimes, younger age, but paradoxically, higher (i.e., more morning) MEQ scores. Superior STM abilities were associated with younger age only. The relationships between chronotype and trait-like cognitive abilities were similar for both men and women and did not differ between younger and older adults.
The present study demonstrates that chronotype, measured by the MEQ, is highly related to inter-daily stability (i.e., the strength of circadian synchronization). Furthermore, although evening types have superior verbal abilities overall, higher (i.e., more morning) MEQ scores were related to superior verbal abilities after controlling for “evening type” behaviours.