We just finished an evolution class about sexual selection. This, as you probably know, is a really wild subject. In particular, competition among (usually) males can take some strange forms.
Males compete with one another for access to females. There are different ways of doing this, depending on the animal species. Male gorillas produce few sperm because they maintain their harems by physical force. Male chimps produce lots of sperm because they mate promiscuously. A male gorilla maximizes his paternity by fighting, a male chimp by flooding away the sperm of other males. And humans are in between. But humans and some other animal species have another mating system—monogamy—that is yet a different way of maximizing the assurance of paternity.
Males also compete for the attention of females. Obvious examples are the songs and plumage of (usually) male birds. In humans, according to Geoffrey Miller’s book The Mating Mind, it can include hunting, sports, language, music, art, religion, etc. Nearly all of the mental capacities that we think of as uniquely human may be the result of sexual, not natural, selection. For example, big-game hunting (whether by stone age tribes or by Oklahomans hunting bucks) provided and provides relatively few calories. It was and is mostly a way of males showing off. And people who can speak most elegantly, play the best music, and commune with the gods most effectively may attract the most and/or the best mates (this can apply equally to men and women).
That’s where I ended, and that’s as far as the science goes. But I feel the need to tell them something else. They may have ethical and religious reasons for believing in the moral superiority of monogamy and the reality of religious experience. I am not saying, for example, that every time a preacher gets on the radio or television, he is trying to win access to mates, although there are numerous examples of this. (For example, the notorious preacher Garner Ted Armstrong kept a list of female undergrads at Ambassador College whom he would regularly call up and pressure into having sex.) I am not saying that every time a skilled musician spends hours practicing then gives a performance, he or she is trying to get in bed with an admiring mate, although this seems to have figured prominently in the lives of some composer-performers such as Franz Liszt and Niccolò Paganini, as well as numerous rock stars. But I am saying that this is how sexual selection produced the human mental capacities for monogamy, religion, and music. Today, a musician today might perform for the sake of pure art, but the “mating mind” would not have a physical thrill from music were it not for thousands of years of sexual selection.
This is also an example of how both liberals and conservatives can misunderstand evolution. Conservative creationists reject sexual selection in human evolution because they reject evolution. God gave us the capacity for music and religion (as one theologian wrote, God created a “God-shaped hole” in the human spirit that makes us thirst for God) and commands us to be monogamous, and that’s that. But I would say that evolution has put these behaviors, and they are now available as part of our behavioral repertoire to use for any purpose, whether connected with sex or not. Meanwhile, liberals might think that monogamy is an artificial moral system thought up by priests to foist upon deluded followers. But monogamy is a natural part of the human mind—it is not the only mating behavior that evolution has conferred upon us, but it is one of them.