To understand the basic neurological relationship between touch and learning, I called David J. Linden, a neuroscience professor at Johns Hopkins University School of Medicine and the author of Touch: The Science of Hand, Heart, and Mind. I asked Linden what role touch plays in learning.

“It’s not so much that touch is a useful tool for teaching facts and strategies—it’s not as if, when you stroke a student’s arm as they practice algebra, they will learn algebra better,” Linden said. “More than anything else, what touch conveys is ‘I’m an ally, I’m not a threat. Touch puts the recipient in a trusting mental state, and anything you can do to encourage the student to trust the teacher is going to make learning better.”

The sensory experience of touch can’t be divorced from the emotional experience, he explained, because the way humans perceive touch depends on its social context. An arm thrown over your shoulders by a domineering boss is perceived very differently than an arm thrown around your shoulders by a trusted friend, for example. “The sensation is perceived differently because the emotional touch centers in the brain are receiving signals about social nuances, even if the touching is identical,” and these nuances, Linden explained, are one of the reasons it’s so hard for schools to create rules governing touch.