Think that the colour of a woman’s outfit matters? Of course not—to you. But to other women, it can be a problem.
A study published in Personality and Social Science found that women in red were seen to be more sexually available and more of a threat—by other women. In one experiment in the US, 196 participants shown an image of an attractive women in her twenties had to say whether the woman was interested in sex. Half saw her in a white dress, the other half saw her in a red one, and the red was seen as the more sexually receptive colour.
In another experiment, this time in Europe, women were shown an image of an attractive women in her twenties—but this time half saw a women in a red shirt and half a woman in a green shirt. Not only were they asked how interested in sex a woman was, but whether they’d introduced said women to their boyfriends. Red was again seen as more interested in sex, and not very likely to meet many boyfriends.
Researchers are quick to point out that women in red aren’t necessarily advertising sexual availability—other women just see it that way. So, this information probably isn’t that valuable to you, but it might explain some of the cattiness you see when women interact with other women. Not all of it though—no one can explain all that.