How to hyperstimulate a sex-recognition algorithm. Women have higher luminous contrast between their facial skin and their lip/eye color. This contrast effect is influenced not only by degree of lightness but also by degree of redness (source). Women are fairer in complexion because their skin has less melanin and less blood (Edwards and Duntley, 1939).... Read More

The female torso visibly reddens towards the end of the menstrual cycle. Do men unconsciously pick up on this visual cue? (Figure from Edwards and Duntley, 1949) Women vary in skin color over the menstrual cycle. From mid-cycle on, their skin steadily reddens because of an increase in blood flow that peaks in the day... Read More

Averaged female face (left) and averaged male face (right). The key facial regions for gender recognition, in terms of either response time or accuracy, seem to be where facial skin borders the lips or the eyes. The human face is a special visual object. We do not learn to recognize it. Instead, it is processed... Read More

Upper left: average of 22 Caucasian female faces Upper right: average of 22 Caucasian male faces Lower left: white pixels are where the female average is lighter than the male average Lower right: white pixels are where the male average is lighter than the female average To a large degree, we do not learn to... Read More