Women are better able to see colour differences than men, who can see rapidly moving objects more easily, according to US scientists.
Researchers at New York's City University compared the vision of men and women who had 20/20 sight (even if corrected by glasses or contact lenses) and normal colour vision.
When they were asked to describe colours from a spectrum, the men found it harder to make distinctions between colours in the middle, such as bluey-greens.
"Across most of the visible spectrum males require a slightly longer wavelength than do females in order to experience the same hue," wrote study author Professor Israel Abramov.
In a second experiment, men were able to process rapidly changing images better than women.
The researchers believe high concentrations of androgen (male sex hormone) receptors in the visual cortex of the brain, help men process images and spot fine detail. Men have 25 percent more neurons in the visual cortex of the brain than women.
"We suggest that, since these neurons are guided by the cortex during embryogenesis, that testosterone plays a major role, somehow leading to different connectivity between males and females," Professor Abramov said.
Biologists believe these sight differences helped men and women in the hunter-gatherer days — men were able to spot distant animals while women were able to assess forage foods up close.
The study was published in the journal Biology of Sex Differences.