In short, the more attuned to others you become, the healthier you become, and vice versa. This mutual influence also explains how a lack of positive social contact diminishes people. Your heart’s capacity for friendship also obeys the biological law of “use it or lose it.” If you don’t regularly exercise your ability to connect face to face, you’ll eventually find yourself lacking some of the basic biological capacity to do so.
The human body — and thereby our human potential — is far more plastic or amenable to change than most of us realize. The new field of social genomics, made possible by the sequencing of the human genome, tells us that the ways our and our children’s genes are expressed at the cellular level is plastic, too, responsive to habitual experiences and actions.
Work in social genomics reveals that our personal histories of social connection or loneliness, for instance, alter how our genes are expressed within the cells of our immune system. New parents may need to worry less about genetic testing and more about how their own actions — like texting while breast-feeding or otherwise paying more attention to their phone than their child — leave life-limiting fingerprints on their and their children’s gene expression.