Social behavior comes through the body--it is profoundly subtle and sophisticated.
When we have a face-to-face conversation:
We continuously scan body and facial expressions for emotional content. Mirror neurons register intent, movement, and posture. They're motor neurons but they respond to other people's movements and intention. So I can perform a simulation in my own mind and body what you're experiencing in yours. It feeds down into limbic system, [emotional] center of brain, and down to gut via vagus nerve, so I can have a felt sensation of what you're experiencing in your body.
Daniel Siegel calls this the resonance circuit.
With electronic technology we've essentially eliminated the body from the equation. The non verbal components are vital to fully understanding of another person. Take for instance texting: we've eliminated the resonance circuit, we've eliminated the mirror neuron system, we eliminated our guts and we use only a tiny fragment of our capabilities/intelligence and we only get fragments of information disembodied from the source.
Use it or lose it
We are plastic organisms. The resonance circuit is plastic. So when we use these devices compulsively and continuously throughout the day, the resonance circuit atrophies and now it becomes harder to have meaningful interactions with others. These conditions are catastrophic for us. We've eliminated nature by living indoors, we've eliminated social contact by settling for fragments of meaningful interactions, and so we've taken ourselves off our two main life support systems that have developed for millions of years.
Are we designing our bodies into isolation?