Humans have many unique behaviors among animals. For instance, we have a formal language that permits unparalleled communication about things that exist in the past, present, and future. We can be especially jealous and can feel schadenfreude. Yet we share at least one fundamental emotion with many other species: fear. That primordial emotion, as I describe in my latest book, The Nature of Fear, binds us to our past. We are the descendants of a long lineage of successful individuals who got their risk assessments right.
While many evolutionary psychologists focus solely on our hominin ancestors to understand why we act as we do, I suggest that we go much farther back in time and beyond our branch on the tree of life. All animals, past and present, must assess life-threatening predation risks and make decisions to avoid or otherwise manage those risks. It’s a delicate balance: being too fearful is costly if caution means that you miss out on acquiring food, mates, or other important resources. Being too brazen could end very poorly indeed. Successful individuals are those that get these trade-offs right, and because of this, leave relatively more offspring.
Despite some differences in the precise neurochemicals that modulate fear, the neurophysiological mechanisms associated with fear in humans are readily seen across vertebrates. Controlled laboratory studies in rodents and humans have identified identical regions of the brain and “fear circuits.”
But to really understand our fears we have to get outside to study how animals assess and manage predation risk in the wild. This is because context influences all decisions. If you’re hungry, it’s wise to take more risks lest you starve. And, if you’re dominant and can steal food from others at will, perhaps it’s OK to be a bit more cautious.
My students and I have spent more than 35 years studying the antipredator and social behavior in giant clams, fishes, skinks and other lizards, as well as in several species of birds and mammals. I’ve studied and researched antipredator behavior in marmots and wallabies in depth. We’ve even explored antipredator behavior in plant species that rapidly close their leaves when threatened.
One of the main lessons I’ve learned is that risk is ubiquitous, and that it’s impossible to completely eliminate it. Fear is a natural emotion and a potent motivator. Indeed, humans share with many animals a tendency to overestimate risk (it’s better to be safe than sorry!). This makes us vulnerable to politicians with malevolent intentions who make compelling advertisements that efficiently tap into our well-honed neurophysiological fear systems. Once they stoke our fear, they tell us that their proposed policies will guarantee our safety. But think for a moment before you support such fearmongers. Ultimately, we must learn to manage our risks. Trustworthy politicians lead us down a path of efficient risk management and recognize that uncertainty is both natural and ubiquitous.
In The Nature of Fear, I describe how natural expressions of this emotion influence the structure of ecological communities, and I review studies that show how the removal of predators changes entire ecosystems. We know this, in part, because of remarkable experiments where we restore predators to locations where they have been extirpated. To manage predatory risks, animals modify their activity patterns, habitat selection, and their diet. Fear of predators can also reduce an individual’s reproductive success. All of these fear-induced modifications can have a profound influence on both the environment and the distribution and abundance of many species. Fear, it turns out, is an essential ingredient in healthy ecosystems and helps maintain biodiversity.
I find it comforting to know that my fear comes from a long line of my ancestors, both human and nonhuman. It is an inherited treasure, a powerful ally. Yet, it is also an annoying and sometimes intolerable companion. It is a compass that, when calibrated properly, guides us away from danger and toward opportunity. Coopted and mutated, it can lead us down destructive paths that often endanger our own humanity.
Daniel T. Blumstein is an ethologist and conservation biologist. He is a professor in the Department of Ecology and Evolutionary Biology, as well as a professor in the Institute of the Environment and Sustainability, at the University of California, Los Angeles. Read an excerpt of The Nature of Fear.