Why Love Matters summary

As all parents know, babies can be frustrating. Sometimes they won’t stop crying, or eat the vegetables you’ve been trying to feed them for the last half hour. But shouting, bargaining, or “discipline” won’t help. That's because babies simply don’t have the brain capacity to control their behavior. 

A baby can’t consider his mother’s frustration or decide to eat the carrot puree to make her happy. That’s because the social brain, which is responsible for complex emotions, only develops after a baby is born. And this development process isn’t as straightforward as you might think.

Before a baby can learn about human culture, he must first be invited to participate in that culture. This invitation has two interlinked components: the behavior of his carers and the biochemicals in his brain. Together, these make social interaction pleasurable.

As long as parents take pleasure in their relationships with their babies, there’s nothing to worry about. That’s because a relationship dominated by pleasurable interactions fosters a baby’s cognitive development, and lays the foundations for emotional control later in life. And it’s all thanks to the way pleasure stimulates the orbitofrontal cortex.

Genes are a blueprint: they contain a sketch of what a structure might look like, not what it will look like. Put differently, the building process is just as important as the architect’s plans. And when it comes to the brain, social inputs determine how much of the genetic blueprint is ever realized.

A baby is born with all the neurons she’ll ever have. This is decided by genes. But as her brain doubles in size over the first year of her life, all those neurons need to be connected. This work takes place in the world outside the womb. In other words, genetic and social factors interact to determine the final shape of her brain.

Let’s talk about stress. It’s a term most of us associate with things like long working hours or a bad day at the office. It can also come from worrying about how you’re going to put food on the table or how you’ll come up with the money for this month’s rent.

But even though stress comes from many different things, it’s often overwhelming and draining. Most of all, though, it’s often seen as part of being an adult: it’s just what happens when you start paying bills and have a family to take care of, right?

Imagine you’re foraging for berries in the forest. You look up and find yourself staring at a huge and dangerous animal. 

Or imagine you’re low on money but still have enough to cover the rent. But then you’re hit with an unexpected bill, leaving you short on cash and with just one day to make up the difference.

As we’ve seen, a mother’s absence has a profound biochemical effect on her baby. Sometimes, though, the problem isn’t her absence but the quality of her presence. This happens when a baby is at home with her biological parents but is poorly cared for, or when the parents are mentally unavailable despite being physically there.

Research shows, for example, that the children of people who suffer from alcohol addiction have higher cortisol levels than children whose parents don’t have this problem. And, as we’ll see in this blink, the high levels of cortisol and stress are true of the parents as well.

If all goes well, babyhood can be a haven of peace and love. Protected from discomfort, the baby’s brain responds by growing more cortisol receptors. These will provide him with the tools he needs later on in life.

But if babyhood doesn’t go well, the baby’s brain develops an overactive stress response. In the short term, this causes sky-high cortisol levels and a state of permanent stress. In the long term, it may well condemn him to become an anxious adult.