Winnipeg Free Press - PRINT EDITION

Smart people SLEEP LATE

New research bound to re-ignite old debate about early versus late risers

  • Print

Sleep is a fundamental component of animal biology. New evidence confirms that, in humans, its timing reflects intelligence. People with higher IQs (intelligence quotients) tend to be more active nocturnally, going to bed later, whereas those with lower IQs usually retire to bed sooner after nightfall.

The precise function of sleep is arguable. But, accumulating evidence shows that lack of sleep in humans and animals can result in obesity, high blood pressure and reduced life spans. Drowsiness impairs mental performance. For instance, 37 per cent of all motor vehicle accidents are caused by drowsy motorists, according to a University of Pennsylvania study. Even minor sleep deficiencies impact on body chemistry.

According to Juliette Faraco of Stanford University, sleep loss generates a proportionate need for "sleep rebound".

One of the most controversial and significant recent findings is the correlation in humans between the earliness/lateness of sleep preferences and intelligence.

Robert Bolizs at Semmelweist University, and his coworkers, have shown that encephalograms during sleep illustrate how sleep elements are directly related to "wakeful cognitive performance." Studies by researchers H. Aliasson and colleagues show the timing of intervals of sleep "correlates closely" with student academic achievement.

Extensive research by Satoshi Kanazawa and colleagues at the London School of Economics and Political Science have uncovered significant differences in sleep-timing preferences among people, depending on their IQ scores.

People with higher IQs are more apt to be nocturnal night-owls. Those with lower IQs tend to restrict their activities primarily to daytime.

People who prefer to go to bed early, and who are early-risers, demonstrate "morningness," whereas those whose sleep patterns are shifted later demonstrate "eveningness." Researchers say eveningness tends to be a characteristic of those with higher IQs.

According to Kanazawa, ancestral humans were typically diurnal, and that a shift towards more nocturnal activities is an "evolutionarily novel preference" of the type normally found in more intelligent individuals, demonstrating "a higher level of cognitive complexity" in the practitioners.

Recent studies at the University of Bologna suggest early-risers are comparatively more conscientious people. Related studies indicate eveningness is often age-related and that eveningness usually peaks at between 17-21 years of age; thereafter morningness becomes more prevalent.

A 2008 study by psychologist Marina Giamnietro and colleagues indicates evening-types tend to be less reliable, less emotionally stable and more apt to suffer from depression, addictions and eating disorders.

Morningness or eveningness are often genetically-based, according to researchers Lambertus Klei at Carnegie Mellon Univesity, Patrick Rietz at the University of Pittsburgh and their associates. In 2008, studies at Max Planck Institute of Psychiatry demonstrated sleep-time preferences are often inherited, and subsequent data indicates that 50 per cent of sleep-time choices are dictated by genetic factors.

"Hypocretins" are inextricably linked to sleep/wakefulness, according to Stanford University research. Hypocretins react with "wake-up" cell groups, including dopamine.

Sleep parameters vary among animals. Cows, for instance, sleep open-eyed. Horses sleep standing up. Some birds can sleep in flight, others while standing. Dolphins sleep in one-half of their brain while the other half remains awake. Bats need 19.9 hours of sleep every 24 hours, lions need 13.5, rats 13, cats 12.5, whales 5.3, deer 3.1, giraffes 1.9, most birds three to eight and donkeys three.

 

Robert Alison has a PhD in zoology and is based in Victoria, B.C.

Republished from the Winnipeg Free Press print edition January 23, 2010 H11

Fact Check

Fact Check

Have you found an error, or know of something we’ve missed in one of our stories?
Please use the form below and let us know.

* Required
  • Please post the headline of the story or the title of the video with the error.

  • Please post exactly what was wrong with the story.

  • Please indicate your source for the correct information.

  • Yes

    No

  • This will only be used to contact you if we have a question about your submission, it will not be used to identify you or be published.

  • Cancel

Having problems with the form?

Contact Us Directly
  • Print

You can comment on most stories on winnipegfreepress.com. You can also agree or disagree with other comments. All you need to do is be a Winnipeg Free Press print or e-edition subscriber to join the conversation and give your feedback.

You can comment on most stories on winnipegfreepress.com. You can also agree or disagree with other comments. All you need to do is be a Winnipeg Free Press print or e-edition subscriber to join the conversation and give your feedback.

Have Your Say

New to commenting? Check out our Frequently Asked Questions.

Have Your Say

Comments are open to Winnipeg Free Press print or e-edition subscribers only. why?

Have Your Say

Comments are open to Winnipeg Free Press Subscribers only. why?

The Winnipeg Free Press does not necessarily endorse any of the views posted. By submitting your comment, you agree to our Terms and Conditions. These terms were revised effective April 16, 2010.

letters

Make text: Larger | Smaller

LATEST VIDEO

The Whiteboard - Jets' 5-on-3 penalty kill

View more like this

Photo Store Gallery

  • A black swallowtail butterfly land on Lantana flowers Sunday morning at the Assiniboine Park English Gardens- standup photo – August 14, 2011   (JOE BRYKSA / WINNIPEG FREE PRESS)
  • Someone or thing is taking advantage of the inactivity at Kapyong Barracks,hundreds of Canada Geese-See Joe Bryksa’s goose a day for 30 days challenge- Day 15- May 22, 2012   (JOE BRYKSA / WINNIPEG FREE PRESS)

View More Gallery Photos

Poll

What's your take on the Jets so far this season?

View Results

View Related Story

Ads by Google