The scientific jury is still out on whether our species is unique among social mammals in being able to conceptualize mental states—other species, such as chimps, dogs, scrub jays and dolphins, may have some modest capacity in this regard. But there’s absolutely no question that we’re much better at it than the rest of the animal kingdom. We are natural psychologists, exquisitely attuned to the unseen psychological world. Reasoning about abstract mental states is as much a trademark of our species as walking upright on two legs, learning a language, and raising our offspring into their teens.
There is a scientific term for this way of thinking—”theory of mind.” It’s perhaps easiest to grasp the concept when considering how we struggle to make sense of someone else’s bizarre or unexpected behavior. If you’ve ever seen an unfortunate woman at the grocery store wearing a midriff-revealing top and packed into a pair of lavender tights like meat in a sausage wrapper, or a follicularly challenged man with a hairpiece two shades off and three centimeters adrift, and asked yourself what on Earth those people were thinking when they looked in the mirror before leaving the house, this is a good sign that your theory of mind (not to mention your fashion sense) is in working order. When others violate our expectations for normalcy or stump us with surprising behaviors, our tendency to mind-read goes into overdrive. We literally “theorize” about the minds that are causing ostensible behavior.
The evolutionary significance of this mind-reading system hinges on one gigantic question: Is this psychological capacity—this theory of mind, this seeing souls glimmering beneath the skin, spirits twinkling behind orbiting eyes, thoughts in the flurry of movement—is this the “one big thing” that could help us finally understand what it means to be human? Could it tell us something about how we find meaning in the universe?