Why We Are Still Social

Some years ago, when I first began writing about the evolution of human sociality, a colleague put to me the question: Why are humans still social? That “still” was weighty with meaning—the idea of a primal solitary state, to which humans might return, perhaps finally freed from group living by technological progress. I was dumbfounded. Humans have no choice but to live in groups. They are unable to reproduce and survive to reproductive age without a group, which makes them obligately interdependent. That interdependence is inscribed upon the body. We lack natural defenses such as impressive canines or tough hides. We have an extended, care-intensive infancy. And we have traits, such as omnivory and tool making, that enabled humans to exploit rainforests and tundra, but that create dependence on collective knowledge and cooperative information sharing. Humans are still social because they must be.

My colleague understood all this. He was asking a theoretical question. From the “gene’s eye view” of evolution, standard in evolutionary psychology, solitary life is the default assumption. Group living has considerable downsides: the spread of disease, competition for mates, and exploitation by free riders to name just a few. Unless group living has advantages (in terms of an increase in the number of copies of a given gene) that outweigh the costs (the decline in number of gene copies), groups would logically disperse. The logic is indisputable. The anthropomorphic metaphor is a shortcut to saying that any heritable genetic variation that resulted in a relative advantage to the organism in its survival and reproduction would increase the frequency of those genes in a population. The organism may be altruistic, cooperative, self-interested or even eat most of its own offspring so long as more copies of its genes, relative to the competing alternatives, are passed to succeeding generations.

The problem with the gene’s eye view is the uses to which we want to put it. Genes are below the level of the organism. The gene’s eye view is blind to the distinctions between social and asocial organisms (Caporael, 2007). As a result, the same theory serves for any species, oysters to humans, given what we know—or think that we know—about the species. Yet in psychology, one reason we turn to evolutionary considerations is that we really do not know what are the “basic units” for describing our species. (The temptation is to say adaptations are the basic unit, but there is still a lot of debate about what are adaptations and how do we know them when we see them?) Acknowledging that we are interdependent, group-living animals may take us closer to developing theories to understand the human mind.

The Minimalist Scenario

Most behavioral scientists would agree that humans have evolved to live in groups, at least for protection from predators and some degree of food sharing. However, it helps to draw out the implications of the evolutionary dynamics. The earliest bipedal ancestors were about a meter tall, lacked tools, had a brain the size of a chimpanzee’s, but lacked its strength and impressive canine teeth. As solitary individuals, they would have been more likely to be the dinner than the diner in their local neighborhoods. Like other primates, they probably deterred predators with alarm calls and mobbing. A weaponless group of hominids, jumping up and down waving their arms at a leopard is more likely to survive than the lone bipedal forager. A fruit tree or a ripe zebra carcass is more food than a solitary hominid could eat and more likely to be found by a group of searchers than a single pair of eyes. Even these simple tasks require some degree of coordination, not unusual in the animal world. For our early ancestors, group living buffered individuals from the risks of predation and starvation.

A group can be only so large, limited as it is by the carrying capacity of the habitat and the distance that can be walked. However, too small a group may fail to buffer individuals. The upper and lower limits on group size creates a competition for “niches” in the group. Over time it would result in the evolution of perceptual, affective and cognitive processes that support the development and maintenance of group membership. In a nutshell, the minimalist scenario states: To the extent that exploiting a habitat is more efficient as a collective rather than an individual process, not only would better coordinated groups prevail, but so also would individuals that were better adapted to group living. Being adapted to group living does not imply self-sacrifice or “genes for” altruism. Selection occurs at two levels, individual and group, and as a result, humans are ambivalently social, engaged in a perpetual juggling act between individual identity, interpersonal relationships and collective interests simultaneously (Brewer & Caporael, 2006).

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