By any reasonable standard, human beings are born way too soon, thrust into a world for which we are not ready. Not even close.

The strange timing of our birth reflects the tradeoffs of biology. Humans have a big brain. This big brain comes with obvious advantages. But it also leads to a serious design problem: the female birth canal, which shrank during the shift to bipedalism, is too narrow for such a large skull.

This is known as the obstetrical dilemma. Natural selection solved this dilemma in typically ingenious fashion: it simply had human babies enter the world before they were ready, when the immature central nervous system was still unable to control the body. (As the development psychologist David Bjorklund notes, if human infants “were born with the same degree of neurological maturity as our ape relatives, pregnancy would last for 21 months.”) The good news is that such premature births reduce the risk to the mother and child. The bad news is that it means our offspring require constant care for more than a decade, which is roughly twice as long as any other primate.

Such care is grueling; there’s no use pretending otherwise. Hillard Kaplan, an anthropologist at the University of New Mexico, estimates that it takes approximately 13 million calories to raise a child from birth to independence. That’s a lot of food and a lot of diapers.

But childcare is not just about the feeding and shitting and sleeping. In fact, taking care of the physical stuff ends up being the easy part. As every parent knows, what’s much harder is dealing with the emotional stuff, that whirligig of moods, desires and tantrums that define the immature mind. The world fills us with feelings, but kids don’t know how to cope with these feelings. We have to show them how.

In a new paper published in Psychological Science, a team of researchers led by Dylan Gee and Laurel Gabard-Durnam (lead authors) and Nim Tottenham (senior author) outlined the neural circuits underlying this emotional education. Although there is a vast amount of research documenting the importance of the parent-child bond – secure attachments in childhood are associated with everything from high school graduation rates to a lower-risk of heart-disease as an adult – the wiring behind these differences has remained unclear.

The main experiment involved putting 53 children and teenagers, ranging in age from four to seventeen, into an fMRI scanner. (To help the younger kids tolerate the confined space, the scientists had them participate in a mock session before the experiment. They also secured their head with a bevy of padded air pillows.) While in the scanner, the children were shown a series of photographs. Some of the pictures were of their mother, while other pictures were of an “ethnicity matched” stranger. The subjects were instructed to press a button whenever they saw a smiling face, regardless of who it was.

When analyzing the fMRI data, the scientists focused on the connection between the right side of the amygdala and the medial prefrontal cortex (mPFC). Both of these are promiscuous brain areas, “lighting up” in all sorts of studies and all kinds of tasks. However, the scientists point out that the right amygdala is generally activated by stress and threats; it’s a warehouse of negative emotion. The mPFC, in contrast, helps to modulate these unfortunate feelings, allowing us to calm ourselves down and keep things in perspective. When a toddler dissolves into a tantrum because she doesn’t want to wear shoes, or go to bed, or eat her broccoli, you can blame her immature frontal lobes, which are still learning how to control her emotions. Kids are mostly id: this is why.

Here’s where things get interesting. For children older than ten, there was no significant difference in right amygdala/mPFC activity when they were flashed pictures of their mother versus a stranger. For younger children, however, the pictures of the mother made a big difference, allowing them to exhibit the same inverse connection between the amygdala and the mPFC that is generally a sign of a more developed mind. The scientists argue that these changes are evidence of “maternal buffering,” as the mere presence of a loving parent can markedly alter the ways in which children deal with their feelings. Furthermore, these shifts in brain activity were influenced by individual differences in the parent-child relationship, so that children with more secure attachments to their mother were more likely to exhibit mature emotional regulation in her presence. As John wrote in the Gospels, “Perfect love casts out fear.” Put more precisely, perfect love (and what’s more perfect than parental love?) allows kids to modulate the activity in the right amygdala, and thus achieve an emotional maturity that they are not yet capable of on their own.

While Gee, et. al provide new clarity on the wiring of this developmental process, scientists have known for decades that the process itself is exceedingly important. Although we tend to think of the human body as a closed-loop system, able to regulate its own homeostatic needs, the intricacies of the parent-child relationship reveal that we’re actually open-loops, designed to be influenced by the emotions of others. Children, in fact, are an extreme example of this open-loop system, which is why not experiencing parental buffering in the first few years of life can be such a crippling condition. Born helpless, we require an education in everything, and that includes learning to tamp down the shouts of the subterranean brain.

The child psychiatrist Donald Winnicott once observed that the goal of a parent should be to raise a child capable of being alone in their presence. That might seem like a paradox, but Winnicott was pointing out that one of the greatest gifts of love is the ability to take it for granted, to trust that it is always there, even when it goes unacknowledged. In Winnicott’s view, the process of maturity is the process of internalizing our attachments, so that the child can “forgo the actual presence of a mother or mother-figure.”

This study is a first step to understanding how this internalization happens. It shows us how the right kind of love marks the brain, how being attached to someone else endows children with a newfound maturity, a sudden strength that helps them handle a world full of scary things.

Gee, Dylan G., et al. "Maternal Buffering of Human Amygdala-Prefrontal Circuitry During Childhood but Not During Adolescence." Psychological Science (2014): 0956797614550878.