"The brain is a computer, both hardwired from birth and programmed by the environment." Obviously the brain isn't really a computer, yet you can read the preceding sentence and intuitively grasp its meaning. Almost all humans have an innate ability to use symbols, metaphors, and figures of speech. Items and phrases can become holy or obscene simply because of what they signify. Where does our amazingly versatile metaphorical brain come from?
In an op-ed for the New York Times, Stanford neuroscientist Robert Sapolsky explains this amazing capacity. Human beings have one million times more neurons than a fruit fly. It is the vast size of our neural network that provides us with the complexity we need for language, fine motor control, long-term planning and other human specialties. He proposes that this complex brain developed a work-around that allows us to use symbols. For example, if we hear about a con man taking advantage of a kind elderly widow, we might feel disgust. But the disgust we feel doesn't come from a special moral center; instead, our outrage happens in the insula, the same part of the brain that handles disgust from rotten food and feces. So evolution “retrofitted” the insula to do a much wider range of functions than it originally did—including allowing us to experience moral disgust. Many other of our complicated moral and psychological responses also have their roots in very basic parts of the brain. As a consequence, the literal and the metaphorical happen in the same place.
Sapolsky shares some examples:
In a remarkable study, Chen-Bo Zhong of the University of Toronto and Katie Liljenquist of Northwestern University demonstrated how the brain has trouble distinguishing between being a dirty scoundrel and being in need of a bath. Volunteers were asked to recall either a moral or immoral act in their past. Afterward, as a token of appreciation, Zhong and Liljenquist offered the volunteers a choice between the gift of a pencil or of a package of antiseptic wipes. And the folks who had just wallowed in their ethical failures were more likely to go for the wipes. In the next study, volunteers were told to recall an immoral act of theirs. Afterward, subjects either did or did not have the opportunity to clean their hands. Those who were able to wash were less likely to respond to a request for help (that the experimenters had set up) that came shortly afterward. Apparently, Lady Macbeth and Pontius Pilate weren’t the only ones to metaphorically absolve their sins by washing their hands.
This potential to manipulate behavior by exploiting the brain’s literal-metaphorical confusions about hygiene and health is also shown in a study by Mark Landau and Daniel Sullivan of the University of Kansas and Jeff Greenberg of the University of Arizona. Subjects either did or didn’t read an article about the health risks of airborne bacteria. All then read a history article that used imagery of a nation as a living organism with statements like, “Following the Civil War, the United States underwent a growth spurt.” Those who read about scary bacteria before thinking about the U.S. as an organism were then more likely to express negative views about immigration.
In Sapolsky's estimation, evolution has "duct-taped metaphors and symbols to whichever pre-existing brain areas provided the closest fit." Our brains can't cleanly distinguish between the real and the symbolic, and the lines blur.
photo by Wei-Chung Allen Lee, et al.