Friday, March 1, 2013


Neuroscientists prove what we always suspected: the two sexes see the world differently



 

If you’ve ever found yourself at a paint store with a member of the opposite sex trying to decide between, say, “laguna blue” and “blue macaw,” chances are you’ve disagreed over which hue is lighter or looks more turquoise.

Take comfort in the fact that the real blame lies with physiology: Neuroscientists have discovered that women are better at distinguishing among subtle distinctions in color, while men appear more sensitive to objects moving across their field of vision.

Scientists have long maintained that the sexes see colors differently. But much of the evidence has been indirect, such as the linguistic research showing that women possess a larger vocabulary than men for describing colors. Experimental evidence for the vision thing has been rare.

That’s why Israel Abramov, a psychologist and behavioral neuroscientist at CUNY’s Brooklyn College, gave a group of men and women a battery of visual tests. Abramov has spent 50 years studying human vision—how our eyes and brain translate light into a representation of the world. He’s curious about the neural mechanisms that determine how we perceive colors.

In one study, Abramov and his research team showed subjects light and dark bars of different widths and degrees of contrast flickering on a computer screen. The effect was akin to how we might view a car moving in the distance. Men were better than women at seeing the bars, and their advantage increased as the bars became narrower and less distinct.

But when the researchers tested color vision in one of two ways—by projecting colors onto frosted glass or beaming them into their subjects’ eyes— women proved slightly better at discriminating among subtle gradations in the middle of the color spectrum, where yellow and green reside. They detected tiny differences between yellows that looked the same to men. The researchers also found that men require a slightly longer wavelength to see the same hue as women; an object that women experience as orange will look slightly more yellowish to men, while green will look more blue-green to men. This last part doesn’t confer an advantage on either sex, but it does demonstrate, Abramov says, that “the nervous system that deals with color cannot be wired in the exact same way in males as in females.” He believes the answer lies in testosterone and other androgens. Evidence from animal studies suggests that male sex hormones can alter development in the visual cortex.

While Abramov has an explanation for how the sexes see differently, he’s less certain about why. One possibility—which he cautions is highly speculative—is that it’s an evolutionary adaptation that benefited hunter-gatherer societies: Males needed to see distant, moving objects, like bison, while females had to be better judges of color when scouring for edible plants.

Someday, further studies could reveal whether these traits could have implications for how men and women perform in fields such as the arts or athletics. At the very least, Abramov says, women probably have an edge nabbing the ripest banana on the shelf.




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