[social grooming] we are held together by unspoken contacts
My colleagues and I have found that, since humans have much bigger social groups than nonhuman primates, our species must be using more sophisticated bonding mechanisms than simple physical grooming—for instance, laughter, singing and dancing. We have also concluded that the function of social grooming is to activate the brain’s endorphin receptors. These activities give us a mental and physical “social high.”
We do not love people so much for the good they have done us, as for the good we do them.
Love does not consist of gazing at each other, but in looking outward together in the same direction.
It is not a lack of love, but a lack of friendship that makes unhappy marriages.