Sex and Intelligence

What's the point of us, exactly?  Niels Bohr is supposed to have said that a physicist is just an atom’s way of looking at itself.  Maybe we're just one of nature’s ways of appreciating her own intense and terrifying beauty. 

But how'd we get so smart?

Why did our intelligence evolve the way it has?  Seems obvious: intelligence is a really good survival trait that lets us solve far more complex and dynamic problems than hard-wired instinct can. 

But if that were the whole story, we’d only be able to think like engineers. 

A major part of our intelligence can be explained not by natural selection but by reproductive selection.  Intelligence is crucial for choosing a good mate — and no other decision has as big an effect on the success of your genes as your choice of mates. 

Think of all the things you have to assess to make a good choice — you have to be able to read people very well, see through their pretenses and assess their potential as partners on all kinds of criteria, and you usually don't have a lot of time to make those, assessments, both for competitive reasons and because the urgent desire to get laid keeps pushing at you. 

I would argue that our amazing intuitive powers evolved precisely because they help us rapidly identify just the right people with whom to form those deep and dangerous mating bonds.  

Geoffrey Miller, in his wonderful book, The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature, goes further to argue that all of what we'd describe as artistic, creative and even spiritual in the human psyche has been produced through the process of sexual selection.  If you accept how important intelligence has been as a factor in human success, it's hard to deny how important a predictor of offsprings' success it would be as well, and therefore what a huge advantage it would be to choose an intelligent mate.  Still, people like Steven Rose of the Open University persist in viewing this kind of link between sex and intelligence as "wholly unacceptable" and "frankly, pornographic." 

There are clues, however, in subtle differences in male and female IQ variations observed 30 years ago by Robert Lehrke of Brainerd State Hospital in Minnesota that support the idea that early human females chose mates for their intelligence. Furthermore, recent work by a German team of geneticists led by Horst Hameister, Ulrich Zechner and others at the University of Ulm has shown that genes related both to fertility and to intelligence tend to cluster on the X chromosome more than would be expected if they were not being selected for sexually (see Trends in Genetics volume 17 page 697, and New Scientist volume 174 issue 2344 of 25 May 2002 page 26). 

Of course, we're still all big fans of physical beauty, but in the end for most of us, it's wit and charm and the capacity for deep intimacy that we choose over everything else — we do end up eroticizing intelligence and falling for deep connections.