5 Things an Alien Scientist Would Find Weird About Humans

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The Ape That Understood the Universe by Steve Stewart-Williams is a fantastic book about the evolution of human psychology and culture. It is packed with seriously interesting information from evolutionary psychology and memetics.

Here are five ideas about humans described in the book.

1. There are "proximate" and "ultimate" causes of human behavior. Why do people have sex? One reason is that it feels good. Another is that it leads to children. The pleasure of sex is the proximate cause, the immediate driver of the behavior. Sex typically isn’t motivated by a desire to reproduce, it’s more often motivated by a pursuit of pleasure. But why did we evolve to find sex pleasurable? Because it leads to children. Having kids is the ultimate cause of sex. As Stewart-Williams puts it, “When evolutionary psychologists argue sex is about making babies, they’re talking about the evolutionary function of the behavior, not what people want.” In fact, the feeling of pleasure itself evolved, because the activities that give rise to the feeling had some payoff in our evolutionary past.

2. Our evolution can help explain disease risk. The book details a potential explanation of why modern women have a breast cancer risk as much as 100 times higher than that of pre-agricultural women. For most of human history, women spent a large portion of their reproductive years either pregnant or breastfeeding. This meant that they didn’t menstruate as often as today. In hunter-gatherer conditions, a woman would have about 100 menstrual cycles in her lifetime. In the modern world, women reach puberty at earlier ages, have fewer pregnancies, and spend less time nursing. Today, women have as many as 400 menstrual cycles. This exposes them to higher levels of ovarian hormones and fluctuations, which increases the odds of breast cancer.

3. Love might be mismatched for the modern world. For most of human history, people lived in small-scale communities of around 150 people. Mating opportunities were limited. Thus, if a person entered a relationship, they formed a deep bond with the other person, in part because there weren’t many options. In the modern world, we still experience such bonds. Even though we live in urban areas full of potential partners and can even open an app to meet someone new, we still care deeply about our mating partners and experience pain upon losing them. From the book: “The excessive tenacity of love may, in other words, be a result of evolutionary mismatch.”

4. There are different male and female sexual strategies. Sex is enjoyable for men and women. In our evolutionary past, though, sex posed far higher risks for women compared to men. One reason is that women could get pregnant, which was often hazardous in small-scale societies. As a result, women are more selective about who they enter romantic relationships with. Even with modern birth control technology, women are still choosier, in part because although the environment has changed, aspects of our evolved psychology have not. The book describes a study in which an attractive young man approached women and ask if they’d like to go back to his apartment; 6 percent said yes. In a different version of the study, an attractive woman approached men and asked if they’d like to go back to her apartment; 69 percent of men said yes. Stewart-Williams suggests another way to look at differences is to consider how men and women approach sex in situations with few constraints. In one study, researchers found that in San Francisco in the 1970s, 75 percent of gay men reported having had more than 100 sexual partners, while 2 percent of lesbians reported more than 100 sexual partners.

5. The selfish meme. This might be the weirdest part of the book, and perhaps the most interesting. Memes are “units of culture: ideas, beliefs, practices, and anything else that can be passed on via social learning.” Memes are analogous to genes. Just as some genes are more likely to survive and replicate, the same holds true for memes. Some ideas and practices are more useful than others, and are thus more likely to survive. But here’s the weird part: The determining factor for whether a meme will be passed on is whether survival benefits the meme itself, not the person using it. Just as a gene doesn’t “care” about the survival of an organism, but rather the survival of itself, a meme doesn’t “care” about the survival of the meme-holder, but simply its own survival. Memes are not conscious any more than genes are conscious. They simply act in a way to maximize their own survival. Some memes go extinct, and others proliferate. It is true that some memes help us (moral norms, for example). But other memes can actually be evolutionarily detrimental (similarly, some gene variants can benefit us, while others can put our health at risk).

The book offers different religious denominations as an example. Some religions promote fertility, urging their meme-holders to have lots of kids. The meme-holders then inculcate their kids with the memes, which benefit the meme’s survival. Other religions enforce abstinence. For instance, the Shakers were an 18th-century American sect that insisted on strict celibacy. Over time, the Shakers became extinct. Stewart-Williams describes Shakerism as a “sterilizing parasite.” Beyond Shakerism, it may be possible that other memes urging people to not have children or have more children are similar. And over time, such memes have the same sterilizing or procreative effect.

The book has so much more. Steve Stewart-Williams also has a terrific Twitter page @SteveStuWill, full of interesting psychology facts and findings.

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