4. Survival and Reproduction

We can understand life in two terms: survival and reproduction. One of the most important components to survival is the concept of resources, that is, any object or factor that increases the chance of survival and reproduction; in other words, it increases fitness. A few examples are food, shelter, land, relationships, time, and energy. Natural selection favors adaptations that maximize resource acquisition. 

The reason genes make bodies that can move is so they can do so in a way that increases fitness. To guide this movement, the nervous system has feelings. A feeling is a signal that draws you toward anything that will increase your chances of survival and reproduction and away from that which decreases them. Pleasure is a signal that what you are doing is increasing fitness, whereas pain is a signal that what you are doing is decreasing it. Feelings are temporary guides. The genes only care about pursuing their quest across generations, not the long-term happiness or suffering of their temporary host. Yet as humans, we can understand the mechanisms and override the genetic tendencies to seek short-term pleasure in pursuit of a more sustained well-being or happiness. 

Resources are finite, which means that life is inherently competitive. It is also innately tragic. This is because often for something to live, something else has to die. Suffering due to disease, starvation, predation, ostracism, sexual frustration, environmental disaster, and psychological stress are part of a healthy ecosystem. Most beings that come into existence live brief, painful, frightening lives. As world-renowned evolutionary biologist Richard Dawkins put it, “it’s not just that there is horror, it’s actually that natural selection produces horror; it’s a horrible process that produces wonderful elegance.”

In terms of the gene, survival is only useful if it leads to reproduction. There are two main reproductive frameworks. Most organisms adopt the R strategy, which uses high amounts of reproduction where a few are lucky or fit enough to survive. In contrast, the K strategy involves lower rates of reproduction, fewer offspring, but heavy parental investment to assure offspring survival. Such animals include humans, apes, dolphins, bears, elephants, and a few others. 

Within these two frameworks fall the casual mating and pair bonding approach. Casual mating strategy involves reproducing with multiple partners but without forming attachments. Usually, but not always, this falls under the R-strategy. Pair bonding means two animals form a long-term relationship to increase the chances of offspring survival. Humans are pair bonders, but not exclusively. Other examples include wolves, gibbons, swans, penguins, and beavers. (Incidentally, the pair bond is designed to last through raising the child, not necessarily for life; it is not surprising that many marriages don’t last.)

In people, there are many noteworthy psychological distinctions between male and female humans. Some of them arise from the fact that the woman can only have one child every nine months, whereas the man can theoretically impregnate women constantly. The sex that invests more, in this case the female (though pregnancy and breastfeeding), is the sex that is going to be more discriminating when choosing a mate. The more you invest, the more you have to lose. As she can only have so many children, she cannot afford to have one with bad genes. (This is why rape is so detrimental to the woman—the system is reacting to the potential loss of several years taking care of a child with genes she did not approve.)

Because the woman has a lower mating opportunity cost (she can’t have other children while pregnant), and because she has parental certainty (she can always be sure that the child is hers), the offspring is more valuable to her. The best way to protect offspring is to acquire resources. She does this by choosing a mate who is both willing and able to commit to long-term paternal investment. Women generally prefer men who are ambitious, healthy, strong, intelligent, and high in status. The reason is these qualities mean that he is likely to have access to resources. Women also like kind, dependable, and stable men because these qualities often mean that he is likely willing to invest. (It is no secret that adding a pet to a man’s profile picture on a dating site increases female engagement; he is advertising his parenting skills.)

By committing to one woman, the man may give up the opportunity to have many children with multiple partners. However, because his resources are so valuable to the woman, he can use them to bargain his way to a higher-quality mate than he might otherwise have access to. This way his offspring will be of higher genetic quality. Furthermore, through his provisioning, there is a better chance his child will survive. It can be costly for the woman to sleep with the wrong mate, whereas for the man the cost of raising a child that isn’t his could be detrimental. Women bear the weight of pregnancy; men bear the weight of paternal uncertainty. The wedding is for the woman’s benefit—proof of male investment. The honeymoon is for the man’s benefit—keep the woman away from others while he makes sure that the child is his! 

Just as women look for certain qualities in men, the same is true in reverse. It is indeed accurate that men, on average, seek youth and beauty. This is because a young woman has many remaining reproductive years, and what we consider universally beautiful indicates either high fertility or low mutation load (greater genetic quality.) Shiny hair, full lips, clear skin, large eyes, and facial symmetry are all signs of health, reproductive value, and the high level of estrogen that accompanies fertility. The waist-to-hip ratio is also important. The indentation needs to be clearly visible because it helps the man detect whether the woman is pregnant. As we’ve noted, he cannot afford to commit his resources to another man’s genes. This is one of the main reasons we consider excessive body fat unattractive in women—it suggests pregnancy. Women use makeup because it mimics the natural cues of sexual arousal. As evolutionary psychologist David Buss puts it, beauty is in the adaptations of the beholder.

Pair bonding is a long-term mating strategy, but humans also engage in casual mating, a short-term strategy. The advantage to the man is that he may pass on genes without the cost of investment. The advantage to the woman is that if the resulting child is a son, he will potentially inherit his father’s proclivity for short-term mating—in turn, the son will have more offspring. Men show greater affinity for casual mating than women do. The result is that within such endeavors, men lower their standards and women raise theirs. This is one way a woman can increase the genetic value of her child—forgo paternal investment, but gain higher quality in her offspring. Some men engage in deception by advertising that they are looking for a pair bond when they are not. This often occurs subconsciously; a lie is more convincing if the liar believes it’s true. Deception and self-deception can be adaptive. 

I’ve been referring to genetic quality. Not all genes are equal, and remember that we measure value in terms of the survival and reproductive ability of the genes. Good genes have fewer mutations, and although occasionally a mutation is by chance adaptive, generally they are mistakes. Beauty and intelligence mean low mutation loads. It is in the animal’s nature to reach for a partner just above their own mate value to ensure the offspring’s fitness. However, there are thousands of genes, some desirable and some less desirable, within the same person. This results in great choice, flexibility, and personal preference. You might value athletic abilities and be willing to compromise on intelligence. Usually, similarities—not opposites—attract, but there are trade-offs happening everywhere, and it’s competitive. Love, in the words of evolutionary psychologist Doug Lisle, is sensing that you have a very good deal. You’ve been over-rewarded, received just a little more than you objectively deserved, and are getting good feedback from someone of high quality. 

You can detect good genes because of fitness indicators. These are traits or behaviors that give clues to your survival and reproductive value. For example, humor is a fitness indicator. We like it because it indicates intelligence, creativity, and flexible and complex cognitive capacities. We engage in hobbies or activities such as singing, dancing, painting, or sports because they are fitness indicators. 

In this discussion we have been assuming that sex must eventually lead to children, and we have implied that men and women want nothing more than to transmit their genes to the next generation. There are some important distinctions here. Genes only want to achieve longevity and guide their host toward that goal. However, as an individual, you can redirect and prioritize your own happiness. As mentioned earlier, genes also encourage the pursuit of pleasure, yet as humans, we can think beyond that. No other animal understands that sex leads to offspring—short-term pleasure costing years of work! Evolution does not simply reward the end goal (gene replication) but provides incentives at each step in the right direction. For example, evolution supports a meaningful connection (relationship), a successful career (resources), or a rewarding hobby (fitness indicator). This is what Doug Lisle has called a “subgoal structure” of human motivation. You can hijack the positive feedback from the genes while devising the best strategy for your own lifetime. 

There is a lot of talk about strategies in evolution. This is because there are many options in the environment. What is best is not always clear-cut, and most choices come with varying costs and benefits. How do we decide? I heard a beautiful explanation during an evolutionary psychology seminar that the aforementioned Doug Lisle gave. First, keep in mind what we have already been through: that a brain is an information-processing, resource-acquisition device. It takes sensory information from the environment, runs it through its innate programs, and takes into account its learned history in the form of memories. There is also the filter of personality, which refers to our individual differences. Although we are comprised of approximately 99.9% genetically similar adaptations, slight variations in the software can significantly affect outcome. (For example, some people are more risk-averse, which alters the dynamic.) It’s important to note that the accuracy of available information drastically impacts both the selected strategy and its success. The more data points, the better the representation, but because nothing can be known for certain in advance, it’s always a gamble based on your parameter estimate. 

The brain assigns each possible choice a value based on benefit minus cost divided by time and energy. It assigns the value of the costs and benefits by estimating probability of success or failure. Don’t worry if this sounds confusing. Luckily, the brain will subconsciously run the calculations for you—at two trillion bits of input data per second. The equation will spit out the option with the highest value. Your conscious mind will get a vague summary with a directive to take action. You won’t really understand why you’ve chosen as you have—it’s too complicated—but often you’ll make up a simple, if incorrect, story about it. What you feel is free will is the oscillation of the cost and benefit as the brain does the work. There is no “you” that gets a final say—your decisions are the equation’s result every time. 

We’ve covered a lot of ground, having analyzed the survival and reproduction machines that we are. Now let’s look at what really makes us human.

*The information from this section is primarily from Evolutionary Psychology: The New Science of the Mind by David Buss, and various talks and podcasts by Douglas Lisle