The Book Was Right: Breasts Are Meant to be Sexy.

     If you want to get your books sold, you have to be careful not to raise the ire of the social media mafia. Take poor old Alex Frith, the author of Growing Up for Boys, a guide to puberty. His publisher has just decided to pulp all the remaining copies because a wowser named Simon Ragoonanan raised a Facebook storm over three sentences: "Girls have breasts for two reasons. One is to make milk for babies. The other is to make the girl look grown up and attractive." Shock! Horror! How could he say such a thing? It makes it sound like women are wired for sex appeal. It's a pity they don't show the same outrage towards those sex education books which encourage unchastity.
    Well, as a trained behavioural scientist, I've got news for Mr Ragoonanan. The book is right!
     If you stop to think about it, certain biological principals should be obvious. In order to perpetuate your genes to the next generation, you not only have to be in good breeding condition, but you have to advertise the fact to the opposite sex. You also have to be able to recognize the same status in potential mates. Thus, animal species have evolved various signs to indicate their status.
     It is not only breeding status. A baby chimpanzee has a tuft of white hair on his bottom. That means, when he annoys an adult and runs away, he flashes a signal saying: I'm a baby; don't hurt me.
    For breeding status it is usually an emphasis on the practical ability to breed, but sometimes it is arbitrary. For instance, you will recall that, when you were growing up, you not only filled out in the right places, but also developed pubic hair. There are good practical reasons why a man should have broad shoulders and a woman broad hips, but the only reason for pubic hair is to reveal that you are no longer a child, but are now a potential father or mother. The hair also retains scent secretions from the apocrine glands, but the scent is also a social signal of maturity.
    Likewise, a man's beard serves no practical purpose except to convey to the world that he is a man - and not a boy or a woman. You perhaps haven't noticed - although the ancient Greek sculptors certainly did - that a man also possesses a low ridge of bone over his eyebrows. This, along with his normally bushier eyebrows, produces a mini-frown, and lends an air of toughness to him - because a woman needs to know that a man can not only give her a baby, but can protect her. His large "Adam's apple", which gives him a deeper, louder voice has the same effect.
     Now let us move to the female of the species. If you watch any group of monkeys and apes long enough, you will notice a couple of things. The first is that the females are sexually receptive only for a relatively short period around the time of ovulation. They usually signal this by their bottoms swelling and, as often as not, turning red. It drives the boys wild. Human females have dropped this signal for a number of reasons. Firstly, as explained in an earlier article, they have evolved the method of keeping the father of their child by their side by offering sex during their infertile period. Secondly, the large muscles in the human buttocks, which hold us upright, tend to make swelling difficult. Also, being upright, humans tend to mate face to face.

Post card acquired by my great-aunt in the first
decade of the twentieth century.

   The other thing about monkeys and apes is that the females are  pretty much flat chested when not nursing a baby. Humans are the only primate whose non-lactating females possess prominent breasts. They are there as a social signal to demonstrate that she is no longer a girl, and can now feed a baby. They are also an erogenous zone.
     So, there you have it: the book was right. If you have boys approaching puberty, go out and order a copy before the publisher destroys them all. If, as a grown up, you wish to know about the origin of human instincts, see if you can obtain a copy of Desmond Morris' bestseller, The Naked Ape. Although it was written fifty years ago, most of its contents have stood the test of time. Indeed, it was instrumental in my taking up ethology, the study of animal behaviour. For a more modern title, try Love Signals by Dr. David B. Givens (1983), which explains in detail the body language used in courtship, how to interpret it, and even how to dress in order to be sexy.