The Moral Animal summary

The view that jealousy is a negative characteristic is pretty widespread. Plenty of people simply rule out relationships with anyone who demonstrates jealous tendencies. But is a life without jealousy even possible? Well, it depends on your stance. Ask evolutionary psychologists, for example, and they’ll tell you that feeling jealous is entirely natural.

That doesn’t mean it’s experienced the same way by both sexes. In fact, males and females experience quite different forms of jealousy. That’s the conclusion of a 1982 study by Martin Daly and Margo Wilson. The two psychologists placed electrodes on the bodies of men and women to measure their physiological reactions to various ideas – specifically, their responses when asked to imagine their partners having sex or bonding emotionally with other people of the opposite sex.

If you’ve seen the 1949 movie Gentlemen Prefer Blondes, you’ll probably remember Marilyn Monroe singing the jazz standard “Diamonds Are a Girl’s Best Friend.” But is it true – are women really that mercenary? Well, according to quite a few evolutionary psychologists, yes.

That’s where cheating comes in. According to proponents of the discipline, few things motivate infidelity like the desire for material wealth. The idea that women receive gifts from their lovers suggests that the more partners they have, the more material goods they’ll receive. It’s pretty much a cliché in popular culture, but there’s also scientific data to back it up. Take a 1979 study by the American anthropologist Donald Symons that looked at bonobos. According to Symons, female bonobos regularly exchange sexual favors with male suitors in exchange for large chunks of meat.

You’ve probably read a hundred fairy tales about a rich young prince falling for the lowly scullery maid and sweeping her away to a life of wealth and happiness. It’s a pretty common theme in stories from around the world. That might just be because there’s some solid evolutionary psychology lurking behind these fantasies.

Here’s the basic insight: social status and wealth play a huge role in determining which gender a family’s favorite child will be. According to evolutionary psychologists, the choice of a favorite reflects an understanding of which child has the greatest potential to propagate his or her genes in the most advantageous way. In poor, low-status families, that’s usually a girl. Why? Well, women have a much greater chance than men of marrying “up” into wealthier families.

Why do we empathize with someone starving in the streets? Well, isn’t altruism just part and parcel of what it means to be human? According to evolutionary psychologists, it’s not quite as simple as that. In fact, as they see it, altruistic behavior is primarily self-serving: we’re kind to others because it establishes a debt in our favor.

Think of it like this: if you give a person who hasn’t eaten for three days something to eat, the chances are he’ll be inclined to go out of his way to help you. That makes a lot of sense when you think about the small, tight-knit communities in which humans evolved. Doing someone a good turn in your community was likely to stand you in good stead. After all, you’d be pretty much guaranteed to see him every day and thus remind him that he owed you a favor. Of course, it doesn’t work out like that in bigger communities, but the evolutionary instinct to help others for self-serving ends still endures.  

Plenty of twentieth-century anthropologists like Franz Boas and Margaret Mead were charmed by the seemingly egalitarian communities of hunter-gatherers they encountered during their travels. They believed they’d found an alternative to the hierarchical class societies of the West. Unfortunately, further research has shown that hierarchies are inherent in virtually every human society.

Take the Ache people of Eastern Paraguay. On the face of it, their society is highly egalitarian. The meat brought back by hunters, for example, is always pooled and divided equally among village members. But when anthropologists Kim Hill and Hillard Kaplan took a closer look in 1988, they realized just how deceptive appearances can be.

All right – we’ve seen that leaders are part and parcel of human societies, and that any number of types of people can fill that role. In this blink, we’ll take a closer look at how actors rise through the ranks to become top dogs. Let’s start by turning to our close cousins the chimpanzees to see how it’s done.

Brute force plays its part in asserting dominance in the world of chimpanzees, but violence alone isn’t enough. In fact, one of the most effective techniques used by these primates is the simulation of strength. That’s something the famous British anthropologist Jane Goodall observed in chimpanzee populations in Gombe, Tanzania, in 1986. During her fieldwork there, she noticed that one of the males – nicknamed Michael – was a lot less brawny than his peers.