DARK, chilly winters seem to sharpen up your mind, a researcher in Norway has
found. Contrary to expectations, we are less prone to memory problems and slow
thinking in winter than in summer.
Since psychiatrists first recognised seasonal affective disorder (SAD) 15
years ago, they have assumed that memory, attention and concentration would
falter as the 鈥渨inter blues鈥� set in. So psychologist Tim Brennen decided to test
the idea. He works at the University of Troms酶, the most northerly university in
the world. Almost 300 kilometres north of the Arctic Circle, residents of Troms
don鈥檛 see the Sun for two months every winter, and bask in two months of
continuous daylight in summer.
Brennen and his colleagues gave 100 Troms酶 residents several standard tests
for attention lapses, impaired memory and slow or foggy thinking in December and
June. To his surprise, people did as well in winter as they did in summer on
most of the tests. The season did make a difference in five of the tasks, but
for four of these, the scores actually improved in winter.
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Brennen can鈥檛 explain why cognitive powers should increase in winter. But the
results at least debunk the idea that they鈥檙e worse. 鈥淲e expected to pick up
winter deficits,鈥� says Brennen. 鈥淭hat effect isn鈥檛 there, and if it isn鈥檛
visible at 69 degrees north, there鈥檚 no reason to think it would be found in
London or New York.鈥�
Svein Magnussen, a cognitive psychologist at the University of Oslo, finds
the results 鈥渧ery unexpected鈥� but reassuring. With up to 10 per cent of the
population suffering some degree of winter depression, he is encouraged that
their thinking will remain clear so they can function adequately. 鈥淏rennen
included a very nice set of tests, from simple to complex,鈥� says Magnussen.
鈥淭hey concern any decision you have to make quickly. In a number of daily
situations鈥攆or example in heavy traffic鈥攖hat could be critical.鈥�
Brennen tested a representative sample of Troms 鈥榮 population rather than
people diagnosed with SAD. So he is aware that SAD patients could still have
slower reactions, lapses memory or reduced mental sharpness. Chris Thompson, a
psychiatrist at the University of Southampton鈥檚 Mood Disorder Clinic, says he
would be surprised not to find such changes in SAD patients.
Brennen thinks that assumption now has to be tested. 鈥淚t鈥檚 still possible
that SAD patients鈥� cognition swings summer to winter,鈥� he says. 鈥淏ut show us the
诲补迟补.鈥�
