There is preliminary evidence that people with blue eyes are less vulnerable than people with brown eyes to so-called ‘seasonal affective disorder’ (SAD) – a low mood that occurs in the dark winter months.

In one study, researchers at the University of South Wales surveyed dozens of students in Wales and in Cyprus and found that those with blue eyes were less likely to describe seasonal effects on their mood.

More research is needed, but a tentative theory is that blue eyes have this protective effect because they are more sensitive to light – in turn, this inhibits the daytime release of melatonin, a hormone that might be responsible for the lethargy experienced by people with SAD.

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Asked by: Mary Jevons, Armley

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Authors

Christian Jarrett
Christian Jarrett

Dr Christian Jarrett is a cognitive neuroscientist, science writer and author. He is the Editor of Psyche, the sister magazine to Aeon that illuminates the human condition through psychology, philosophy and the arts. Jarrett also created the British Psychological Society's Research Digest blog and was the first ever staff journalist on the Society's magazine, The Psychologist. He is author of Great Myths of The Brain and Be Who You Want: Unlocking the Science of Personality Change.

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