2010 study that compared social rejection to physical pain discovered the two “are similar not only in that they are both distressing—they share a common somatosensory representation as well.” The researchers recruited subjects who had recently experienced unwanted breakups of romantic relationships. They studied the participants’ brains in an MRI machine while having them view photographs of their ex partners. They also studied their brains while subjecting them to “noxious thermal stimulation” (uncomfortable heat) on their forearms. They discovered neural overlap: regions of the brain normally associated with physical pain were also activated in the experience of social rejection. The study authors propose that “experiences of social rejection, when elicited powerfully enough, recruit brain regions involved in both the affective and sensory components of physical pain.”
Our species is wired to suffer when others refuse to love us. The pain of social rejection is as real to us, and perhaps even as severe, as a broken limb or a third degree burn.
(This puts the practice of shunning into perspective. Religious sects that punish apostates by shunning them are inflicting literal torture.)
Why should it be that social rejection hurts us so much? In the rest of this section, one possible answer shall be offered, and a broader point about human nature shall be made.
Whitetail deer fawns weigh approximately six pounds at birth, not much less than the average human infant. But unlike our babies, fawns can stand and walk, shakily at first, within 20 minutes of their birth. After a month they are fully mobile, able to follow their mothers on foraging trips. They are weaned about a month after that. A male leaves his mother after just a year. A female leaves after two years, and can have her own offspring soon thereafter.
The life cycle of a human is glacial in comparison. A human baby generally doesn’t crawl until at least seven months after birth, and doesn’t walk until after a full year. Most American mothers stop breastfeeding within a year, but weaning occurs much later in other cultures, and there are compelling reasons to pin the natural weaning age at closer to three or four (or even older!). And young humans don’t reach sexual maturity until they are twelve to fifteen. The cost our species pays for being big brained and bipedal is a prolonged maturation period.
During this period human offspring need to be protected. Youths who don’t stick close by their mothers, or whose mothers who don’t stick close by them, get snapped up by alligators or dragged off by wolves. Evolution developed a trick for keeping mothers and their offspring together.
Of course, a strong mother-child bond is not exclusively human. We see it in baboons, whales, zebras, mongooses – in all mammals, not to mention birds. African elephants not only form such bonds, and not only protect their weak pack members, they also sniff and caress the desiccating bones of long fallen comrades in what appear to be acts of mourning. It is quite possible, and seems likely, that love is not unique to our species. It evolved long ago in some reptile lineage that would later produce mammals, and in one way or another it’s expressed in most of our closer cousins on the tree of life. Love is all around us.
Once love arrived on planet earth via natural selection it could be expanded, contorted, and repurposed, as evolution is wont to do. It would be a relatively small tweak for the tendency in females to bond to their children to become unlocked in males. Bonds could form between mates and then between all members of a family. Genetic kinship is almost certainly the basis for agape, sacrificial love. Such love is naturally selected in the genes of the children who’ve survived thanks to the sacrifices of their parents and other relatives.
Reciprocal relationships probably evolved next. Bonds formed between individuals where cooperation increased mutual chances for survival. Love was repurposed yet again. Friendship arrived on the scene.
Reciprocal relationships are not uncommon in nature. Reciprocation across species is called symbiosis. I’ve seen cleaner wrasses while snorkeling where I live in Hawaii. They make their living by removing parasites and dead tissue from other fish. Their customers tolerate the intrusion because the service provided is truly beneficial. Neither party is doing charity for the other: they both get something valuable out of the transaction.
Consider muskoxen, thick-coated arctic bovids that look similar to bison but are more closely related to sheep. When a herd of muskoxen is threatened, the bulls and cows form an outward facing ring around the calves, a maneuver reminiscent of the circling of wagons by America’s westward bound pioneers. Each animal relies on the horns of its immediate neighbors to defend its sides and flank.
Does it make sense from an evolutionary perspective for a cow to protect any other cow’s offspring, or for that matter a bull to protect any other bull considering that in the mating season they will become competitors? It must, because they do. Reciprocation evolves in social animals because it works. The arctic wolves that prey on muskoxen are also social animals, and within their packs they also form reciprocal relationships. Reciprocation is everywhere in nature.
How does an individual muskox know to do its part in forming the defensive structure? It seems unlikely that a muskox makes a rational decision to form a circle (although a circle is most rational) and then communicates the plan to the others.
We have this idea that animal instincts must be very foreign things, so weakened within our species that we are rarely if ever ruled by them. They’re akin to reflexes, which emerge if you bang the right spot on your knee with a little hammer but otherwise remain mysteriously buried within us. This isn’t logical.
Perhaps emotions are instincts. Instincts are emotions. We are ruled by them constantly, just like muskoxen and wolves are.
Emotion is what drives an individual muskox to take her place in the defensive circle and stand her ground amidst attack. Fear. Anger. Love.
Geese do not post sign up sheets for their gaggles. Each individual goose follows her goosey impulses moment by moment, and finds herself flying in a tightly formed skein with likeminded others without recalling quite how she got there.
As our ancestors’ brains grew larger, their infants became increasingly helpless at birth and reached maturity later and later. The need for cooperation grew stronger and the reciprocal relationships increased in complexity. A wide range of emotions, including guilt, pity, and embarrassment, arose to help navigate sophisticated social bargains. Reciprocal relationships are complex. A balancing act of interests must be achieved. Since cheating gives an obvious advantage, systems must arise to prevent cheating. The conscience arrived on the scene.
Reciprocation is rational because it aids all involved in survival, but the need for reciprocation in our ancestors arose before rational thought had evolved, and so emotions evolved first. Emotions are the instinctual enforcers of self-sacrifice and reciprocation. Some of these emotions feel good. Some hurt.
Sticking together is how our ancestors survived. It’s how they kept their slowly maturing babies safe. Our social instincts allowed our species to grow big brains. Living together presented a new array of problems to solve, in response to which our social instincts became further refined and our brains grew even bigger.
We crave community. We are not like the solitary but social orangutans, who live alone but enjoy brief social interactions when they encounter each other while running their various orangutan errands. We are more like our close cousins the bonobos, who live in fission-fusion societies in which a large troop sleeps together in one locality at night and then breaks into smaller foraging groups during the day. We, like all other hominines (members of the subfamily Homininae, which includes gorillas, chimpanzees, bonobos, and humans, but not orangutans), are built to navigate social hierarchies. We have a primal, instinctual need to form bonds.