Behave: The Biology of Humans at Our Best and Worst

Humans often kill for disrespect to graven images, such as in Islamist fatwas against artists who depict the prophet Mohammed. In gang war, people kill over the color of someone’s sneakers or the clothes people are allowed and not allowed to wear.

One of our unique human capacities is for symbolic representation in language and art. Such symbolic representation has rudimentary forms in other species, such as the “protowords” of vervet monkeys, who have different alarm calls for predators approaching from the ground, air, and trees. But language like ours has the capacity to “pr[y] apart message from its meaning” (557): It operates metaphorically and can represent non-immediate states and abstract concepts through these metaphorical constructs.

Metaphor emerged recently in our cognitive evolution, and our brain handles this new process somewhat oddly. Consider the ACC again, which helps us determine the meaning of physical pain in our bodies but also activates in contexts of social pain. The ACC can also allow us to “feel” someone else’s pain by activating in observation of another person’s injury. Other chemicals—such as the neurotransmitter substance P, which is highly associated with physical pain signaling—are also higher in states of clinical depression with the brain interpreting the complex emotional state as “pain.” The insula, controlling disgust, has similar functions. It activates when we put rancid food in our mouth but also when we think about people or acts we deem “disgusting,” which can trigger the same aversion and nausea responses. All this demonstrates how the brain operates on multiple levels of literal and figurative interpretation, transferring a complex judgement into a reflex reaction to interpret it or take clearer action against it. This is another example in Behave about how much of evolution is a process of working with what you already have to do whatever is necessary. Human and most primate brains, and humans and most primate behavior, is almost identical—humans have just evolved to a slightly higher level of complexity.

This discussion of metaphor in the brain brings Sapolsky to focus more closely on the metaphor of “disgust.” In some sense, the problems moral and gustatory disgust reactions solve are the same. In both cases, we want to rid ourselves of a pathogen threat, be that via food, a person we deem physically or psychologically unclean, or a thought we consider infectious. We also characterize things we like or are attracted to as clean or neat, and acts of physical cleaning, such as doing chores or grooming oneself, also have the effect of cleansing our emotional palettes. Studies also show we seek more physical cleanliness when urged to consider our own ethical misgivings, i.e., our emotional and moral dirtiness. In another study, being instructed to speak a lie predicted more selection of mouthwash as experiment compensation over a neutral object while writing a lie predicted selection of hand soap as a reward. Crucially important, those given the opportunity to physically cleanse themselves or observe someone else cleansing themselves after contemplating their own moral failings were less likely to assist someone in need afterward; many of our moments of prosociality “are acts of restitution, attempts to counter our antisocial moments” (565).

The above are examples of the brain metaphorically equating emotional with physical sensations. We also do the opposite. Various touch signals prime us toward certain emotional and cognitive judgements. If the clipboard someone’s resumé is attached to is heavier, we think of them as more serious. Handle a rough or smooth object, we will judge social interactions of others as smoother or rougher. Hold a warm cup of coffee, experience an individual in a story as warm. Iced coffee, we see them as cold. These are real world examples of human susceptibility to subliminal signals, as introduced in Chapter 3. As such, they are another reminder from Sapolsky that, though we may think of ourselves as logical creatures, much of our “thinking” occurs at levels we neither control nor are aware of. Since this can have some real consequences for people, it is our duty to understand these levels of automaticity in the brain and work to implement behaviors that can correct them.

The Metaphorical Dark Side

In Chapter 10 Sapolsky introduced kin selection and showed that, though all species do kin selection, human kin selection is unique because we interpret it mostly cognitively, not through subliminal signals like pheromones (largely because our smell is so bad we cannot detect many pheromones). Because we do kin selection cognitively, our kin selection dispositions can be manipulated cognitively. By creating rhetoric of dehumanization and disgust, for instance, we can push certain groups out of our kin at a species level and see them as animals or monsters. This figures prominently in genocide, such as the Rwandan genocide of 1994, where the Hutu massacre on the Tutsis engaged various mechanics of dehumanizing Tutsis—calling them rats, cancers, etc. All this plays on the insula, where moral disgust is confused for literal disgust. The consequence of our brain’s metaphorical equation of moral with gustatory disgust in extermination. In this connection of the science of kin selection to the horror of atrocity, Sapolsky provides another application of the science he outlines in the former chapters to the “best and worst” behaviors he outlines in the latter chapters.

Violations of sacred values, or metaphorical concepts cultures see as inviolable, have been shown to be very important in predicting conflict. By the same token, exhibiting acknowledgement and concession to the sacred values of others or establishing shared sacred values are shown as integral to solving conflicts between cultures. “In recognizing the enemy's sacred symbols, you are de facto recognizing their humanity, their capacity for pride, unity, and connection to their past and, probably most of all, their capacity for experiencing pain” (577). A great part of Mandela’s success as a peacemaker in South Africa was his “genius at appreciating sacred values” (578)—negotiating with enemies in their own mother-tongue and holding negotiations in the warm rooms of his home while serving tea and snacks to help remind his guests of a shared humanity.

In this chapter, Sapolsky outlines perhaps the most dire consequence of human predisposition to Us/Theming: genocide. Our capacity for genocide, importantly, relies on our capacity for metaphor because our capacity for metaphor relies on the roping of more ancient brain regions into new, more cognitively complex tasks, e.g., moral disgust using the insula for gustatory disgust. However, because our brain “confuses” these two forms of disgust, we react to the morally disgusting the same way we would the gustatorily disgusting, as a pathogen we need to exterminate. Furthermore, because we are such a metaphorical species relying so much on cognitive rationalizations to structure our world, we are very susceptible to the metaphors others insert into our lives—we can be lied to if the lies are emotionally convincing or the language is logical. Metaphors become very dangerous weapons we must work to contain. However, as his discussion of the genius of Mandela shows, when we understand the metaphors that govern other people’s lives, when we appreciate that to them these metaphors may be sacred, and therefore metaphor can become our most powerful tool toward peace.