The eyes have it: Men do see things differently to women

The way that the visual centers of men and women's brains works is different, finds new research published in BioMed Central's open access journal Biology of Sex Differences. Men have greater sensitivity to fine detail and rapidly moving stimuli, but women are better at discriminating between colors.

In the brain there are high concentrations of (androgen) receptors throughout , especially in the which is responsible for processing images. Androgens are also responsible for controlling the development of neurons in the visual cortex during embryogenesis, meaning that males have 25% more of these neurons than females.

Researchers from Brooklyn and Hunter Colleges of the City University of New York compared the vision of men and women aged over 16 from both college and high school, including students and staff. All volunteers were required to have normal color vision and 20/20 sight (or 20/20 when corrected by glasses or contact lenses).

When the volunteers were required to describe colors shown to them across the it became obvious that the of men was shifted, and that they required a slightly longer wavelength to experience the same hue as the women. The males also had a broader range in the center of the spectrum where they were less able to discriminate between colors.

An image of light and dark bars was used to measure contrast-sensitivity functions (CSF) of vision; the bars were either horizontal or vertical and volunteers had to choose which one they saw. In each image, when the light and dark bars were alternated the image appeared to flicker.

By varying how rapidly the bars alternated or how close together they were, the team found that at moderate rates of image change, observers lost sensitivity for close together bars, and gained sensitivity when the bars were farther apart. However when the image change was faster both sexes were less able to resolve the images over all bar widths. Overall the men were better able to resolve more rapidly changing images that were closer together than the women.

Prof Israel Abramov, who led this study commented, "As with other senses, such as hearing and the olfactory system, there are marked in vision between men and women. The elements of vision we measured are determined by inputs from specific sets of thalamic neurons into the primary visual cortex. We suggest that, since these are guided by the cortex during embryogenesis, that testosterone plays a major role, somehow leading to different connectivity between males and females. The evolutionary driving force between these differences is less clear."

More information: Sex & vision I: Spatio-temporal resolution Israel Abramov, James Gordon, Olga Feldman and Alla Chavarga, Biology of Sex Differences (in press)

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sticklebricks
not rated yet Sep 03, 2012
To me the evolutionary reasons would be due to hunting. Chasing after animals at speed calls for less detail and more speedy image processing (like with other animals found in nature).
Tausch
not rated yet Sep 03, 2012
Why are you disappointed?
You measure associations.
You want differences.
What is a controlled environment?

obama_socks
1.5 / 5 (4) Sep 03, 2012
It wasn't only the hunting for food that made superior eyesight necessary in men, it was also as protector of the women and children. Before doors were invented and our ancestors lived in caves, any flicker of light or shadow, any movement inside or outside of the cave would have caused the defenders to become alert and ready to kill any intruder. Myopia would have been a death sentence, imo.
Smashin_Z_1885
1 / 5 (1) Sep 04, 2012
Smoke some good weed, and you'll notice that the male brain will now have increased capacity for not only color discernment, but also detail assessment and movement perception. The effect is mostly temporary; however, once the THC wears off, the brain remembers the situation, and can re-impliment the scenario at will, by producing increased levels of the body's own THC-like compounds, thereby partially re-instituting the 'high' of the original THC effect . It's quite brilliant, and highly valuable for those who enjoy analyzing fractal shapes in nature, as well as color discrimination. Mostly, this process is done for pure enjoyment and pleasure; however, there may be some sort of functional usage as well, who knows.
ODesign
5 / 5 (1) Sep 04, 2012
The test was brilliant, and the conclusion supported by other evidence, but the editor mangled the details and physics. Hue = wavelength. Alternating white and dark bars would not measure hue perception, they would measure luminosity perception.

The following sentence in the article is one of many that should be corrected to avoid confusing the layman with incorrect word usage.

"it became obvious that the color vision of men was shifted, and that they required a slightly longer wavelength to experience the same hue as the women"

antialias_physorg
5 / 5 (1) Sep 04, 2012
When the volunteers were required to describe colors shown to them across the visual spectrum it became obvious that the color vision of men was shifted, and that they required a slightly longer wavelength to experience the same hue as the women.

Tetrachromacy (having four distinct color cones in the eye instead of three - which gives increased ability to distinguish hues) isn't a new finding.
Since it's on the X chromosom, depending on where you look, you get reported values between a few percent and up to 50 percent of women who have that.
Eikka
5 / 5 (1) Sep 04, 2012

The following sentence in the article is one of many that should be corrected to avoid confusing the layman with incorrect word usage.

"it became obvious that the color vision of men was shifted, and that they required a slightly longer wavelength to experience the same hue as the women"



Indeed. I found it incredible that they'd claim to measure something subjective like that. How on earth would you even test what hues they are percieving? By asking "Is this red?"
Pattern_chaser
not rated yet Sep 04, 2012
I've read it twice now, and I still can't identify the differences (between men and women) that the title of the piece describes. Maybe I'm just not concentrating hard enough....
Torbjorn_Larsson_OM
not rated yet Sep 04, 2012
As ODesign notes, the presentation here is mangled. (The paper is open access.) It is the spatial resolution that is shifted with the contrast modulation of monochrome bars at the same spatially integrated luminance.

@ sticklebricks: The paper discuss such a hypothesis, but it doesn't really test it as these sex differences appears already in mice. It can be a side effect of how sex hormones affect development which is fixed simply by sexual differentiation.

@ antialias_physorg: The paper mentions that, and how especially females but also men can be polymorphic (respectively chimaeric) in relevant genes. They screen for color vision anomalies, but doesn't test if that screens out tetrachromates et cetera.

@ Eikka: No hues, see the paper.

@ Pattern_chaser: It is subtle. They run an ANOVA, you need their raw data.
Sean_W
5 / 5 (1) Sep 04, 2012
It wasn't only the hunting for food that made superior eyesight necessary in men, it was also as protector of the women and children. Before doors were invented and our ancestors lived in caves, any flicker of light or shadow, any movement inside or outside of the cave would have caused the defenders to become alert and ready to kill any intruder. Myopia would have been a death sentence, imo.


While this is a good point, I would only take issue with it being described as "superior" eyesight. It is better adapted to traditional male roles where as women's eyesight is better adapted to female roles. Determining shades of color would be beneficial in noting inflammation or pallor in children, discerning ripe/unripe foods and discerning poisonous/safe plants. This seems to have translated into women having many more names for shades of color than men commonly use. Saffron and goldenrod and such are just refers to as yellow by men, even if they might tell the difference when compared
sirchick
not rated yet Sep 04, 2012
http://www.geekin...lors.jpg

Reminds me of this