I knew about the baby stuff, but not the benefits for adults.

An initial small study, published in the journal Pediatrics in 1986, showed that just 10 days of “body stroking and passive movements of the limbs” for less than an hour led babies to grow 47 percent faster. They averaged fewer days in the hospital and accrued $3,000 less in medical bills.

Touch means you get sick less:

The hug, specifically, has been repeatedly linked to good health. In a more recent study that made headlines about hugs helping the immune system, researchers led by the psychologist Sheldon Cohen at Carnegie Mellon University isolated 400 people in a hotel and exposed them to a cold virus. People who had supportive social interactions had fewer and less severe symptoms. Physical touch (specifically hugging) seemed to account for about a third of that effect.

On the “change” in how much touch is acceptable:

The research is clear on that fact that people both need and react well to physical touch—in controlled environments. There is no evidence that people like to be touched any less than in previous generations, only that negatively received touch is more openly vocalized. What’s new is that people who didn’t appreciate being touched in previous decades, or who were always made uncomfortable by it, especially from people in positions of power, are empowered to process the fact that it’s not something they need to put up with. They have platforms for speaking up, channels for recourse, and supportive listeners to cushion the blowback.

On unwanted touch:

The unwanted hug is an act on a spectrum of submission that produces neurochemical responses similar to any other violation of autonomy, from having a credit-card number stolen to feeling your car lose traction on the highway. A perceived absence of control becomes a spilling of neurotransmitters from the brain into the blood. If a boundary is being redrawn, it’s around people’s ability to continue to make others feel that. The benefits of a hug evaporate when a person perceives it as aggression.

That one reminded me of my wife’s complaints when she was pregnant that random people at the grocery store would come up and touch her belly. She once grabbed someone’s hand to ask “why do you think you can touch me”.