There are two aspects of parenting to discuss here. One is positive touch and the other is responsivity.

When parents are warm and responsive to the child’s needs and desires, the child develops a more agreeable personality, greater conscience, and prosocial behavior. These children show more empathy in our studies. Apparently, if you are treated with empathy, you will treat others the same way. Part of being responsive as a caregiver is giving children the touch that they crave.

Responsivity and touch have a great deal to do with how the brain develops. Babies are born with 25 percent of their brain developed. In the first years of life, the size of the brain reaches adult levels (although there are qualitative changes in sensitive periods through middle age). Lack of touch has physiological effects, shutting down growth hormone and DNA activities when the offspring is separated from the mother. We know from animal studies that mammalian offspring quickly lose physiological balance on multiple levels when the mother is not in physical contact.

We know that the infant’s nervous system is experience-dependent, particularly through an attachment relationship. Like it or not, the caregiver becomes an “external psychobiological regulator,” co-constructing the brain. The baby is just a bundle of nerves and sensory systems when born, and can easily get shocked or wildly distressed because the cortex is not developed enough for self-control. The baby needs the caregiver to keep it calm so the brain systems can develop well. As the brain matures, the external, caregiver-based regulation is transformed into internal regulation. The baby learns ways to comfort itself and learns that distress is quickly soothed, so it does not develop a “stressed brain” or learn a pattern of extreme emotional shifts.

Part of what is being shaped by caregiver touch and responsivity is the neuroendocrine system, which plays a large role in managing stressful situations and bonding to others throughout life. Peptidergic systems that involve oxytocin and vasopressin are shaped in early life. These systems appear to inhibit defensive behaviors associated with anxiety, stress, and fear, and this inhibition may allow for positive social interactions and the development of social bonds. In fact, oxytocin promotes caring relationships and bonding. Oxytocin also counteracts the effects of stress by decreasing blood pressure and reducing activity in the sympathetic autonomic system.

When touch needs are neglected, various things can ensue. Monkeys who are deprived of touch become hyperaggressive, and their spinal fluid has low levels of 5-HIAA, a main metabolite of serotonin, resulting from reduced serotonin production and linked to impulsive violent and anti-social behavior in mammals. We can see the effects in naturalistic and tragic experiments with children. For example, Romanian orphan children who did not receive affectionate touch in the first years of life became incapable of producing oxytocin in response to affectionate touch from their adoptive parents.

Assuming a child has had plenty of good touch in early life, why should you keep touching, hugging, and holding the child as they grow up? And how does this relate to morality?

Holding and positive touch are calming actions that promote positive hormones like oxytocin. Moral action in the moment is often related to one’s mood or feeling state. When people are feeling gratitude, they are more likely to act compassionately toward someone in need, whereas when people are feeling insecure or fearful, they are less likely to help someone in need.