How did we evolve the most loving brain on the planet?
Humans are the most sociable species on earth — for better and for worse.
On the one hand, we have the greatest capacities for empathy, communication, friendship, romance, complex social structures and altruism. On the other, we have the greatest capacities for shaming, emotional cruelty, sadism, envy, jealousy, discrimination and other forms of dehumanization, and wholesale slaughter of our fellow humans.
In other words, to paraphrase a Native American teaching, a wolf of love and a wolf of hate live in the heart of every person.
Many factors shape each of these two wolves, including biological evolution, culture, economics and personal history. Here, I’d like to comment on key elements of the neural substrate of bonding and love; in my next blog, I’ll write about the evolution of aggression and hate; then, in the next several posts, we’ll explore the crucial skill of empathy, perhaps the premier way to feed the wolf of love.
These are complex subjects, so I hope you’ll forgive some simplifications. Here we go.
The growing length of childhood coevolved with the enlarging of the brain — which has tripled in size over the last 2.5 million years, since the time of the first tool-making hominids — and with the development of complex bonding, which includes friendship, romantic love, parent-child attachment and loyalty to a group.
As the brain grew bigger, childhood needed to be longer, because there was so much to learn. To keep a vulnerable child alive for many years, we evolved strong bonds between parents and children, between mates, within extended family groups and within bands as a whole — all in order to sustain “the village it takes to raise a child.” Bands with better teamwork outcompeted other bands for scarce resources; because breeding occurred primarily within bands, genes for bonding, cooperation, and altruism proliferated within the human genome.