The Female Brain by Louann Md Brizendine

attractive wives, between ages twenty and forty, who are an average of two and a half years younger than they are. They also want potential long-term mates to have clear skin, bright eyes, full lips, shiny hair, and curvy, hourglass figures. The fact that these mate preferences hold true in every culture indicates that they’re part of men’s hardwired inheritance from their ancient forefathers. It wasn’t just that Rob had a thing for girls with shiny curls. Melissa’s hair triggered his ancient attraction wiring.
    Why would these particular criteria top men’s lists? From a practical perspective, all of these traits, superficial as they may seem, are strong visual markers of fertility. Whether or not men know it consciously, their brains know that female fertility offers them the biggest reproductive payoff for their investment. With tens of millions of sperm, men are capable of producing an almost unlimited number of offspring as long as they can find enough fertile females to have sex with. As a result, their key task is to pair up with women who are likely to be fertile and reproduce. Pairing with infertile women would be a waste of their genetic futures. So, over millions of years, male brain wiring evolved to scan women for quick visual clues to their fertility. Age, of course, is one important factor; health is another. A high activity level, youthful gait, symmetrical physical features, smooth skin, lustrous hair, and lips plumped by estrogen are easily observable signs of age, fertility, and health. So it’s no wonder women are reaching for the plumping effects of collagen injections and the wrinkle smoothing of Botox.
    Shape, too, is a remarkably good indicator of fertility—breast implants notwithstanding. Before puberty, males and females have very similar body shapes and waist-to-hip ratios. Once the reproductive hormones kick in, however, healthy females develop curvier shapes, with waists that are about one-third narrower than their hips. Women with that body type have more estrogen and become pregnant more easily and at a younger age than those with waists that are closer in size to their hips. A thin waist also gives an instant clue to a woman’s reproductive availability, since pregnancy radically alters her silhouette. Social reputation is often a factor in male assessment, since the most reproductively successful males also need to pick women who will mate only with them. Men want to ensure their paternity but also to be able to count on a woman’s mothering skills to make sure that their offspring thrive. If Melissa had immediately gone to bed with Rob or showed off to him about all the guys she had had, his Stone Age brain might have judged that she would be unfaithful or had a bad reputation. That she was affectionate on the dance floor and went home at a proper hour in a taxi showed him she was a high-quality lady with whom to mate long-term.
    C ALCULATING P OTENTIAL D ANGER
    Rob left a message on her machine, and Melissa waited a few days before calling him back. And although they had kissed on the first date, she had no plans of going to bed with him until she knew more about him. He was incredibly funny and charming, and seemed to have his life in order, but she needed to be sure on a gut level that she could trust him. The brain’s anxiety circuits usually fire around strangers—her amygdala’s fear circuits were still turned on full force. A natural cautiousness toward strangers is part of the brain wiring of both males and females, but women in particular give early, careful scrutiny to a man’s likely level of commitment when looking for a mate.
    Seduction and abandonment by males is an old ruse, going back to the beginning of our species; one study found that young college males admitted to depicting themselves as kinder, more sincere, and more trustworthy than they really are. Some anthropologists speculate that natural selection favored men who were good at deceiving women and