The colour of a person's eyes could give away key personality traits, according to a new study.
Researchers from the University of Queensland and the University of NSW analysed the eye colour of 336 Australians - most with a northern European background. They answered a series of questionnaires measuring aspects of their personality like agreeableness, conscientiousness and neuroticism.
Northern Europeans with lighter coloured eyes tended to be seen as less agreeable and more competitive. They were also more egocentric and skeptical of others, according to the paper published in Current Psychology.
Northern Europeans with darker eyes were seen as more altruistic, sympathetic and willing to help others, they found. Although the same correlation didn't arise with other Europeans.
Researchers believe the link has evolutionary roots, Medical Daily reported.
The cold dry climate of the last Ice Age in northern Europe thousands of years ago forced a shortage of food. Men needed to travel long distances to get supplies, causing them to die off at higher rates than women. Theories suggest competition for care by men was fierce for women and men and women with rare, lighter eyes had an easier time attracting mates.
Previous studies have indicated eye colour could be linked to alcohol abuse, response styles and sociability.