The Wall Street Journal reports on a new study.

It says:

We learn to be afraid. One of the oldest discoveries in psychology is that rats will quickly learn to avoid a sound or a smell that has been associated with a shock in the past—they not only fear the shock, they become scared of the smell, too.

A paper by Nim Tottenham of the University of California, Los Angeles in “Current Topics in Behavioral Neurosciences” summarizes recent research on how this learned fear system develops, in animals and in people. Early experiences help shape the fear system. If caregivers protect us from danger early in life, this helps us to develop a more flexible and functional fear system later. Dr. Tottenham argues, in particular, that caring parents keep young animals from prematurely developing the adult system: They let rat pups be pups and children be children.

Of course, it makes sense to quickly learn to avoid events that have led to danger in the past. But it can also be paralyzing. There is a basic paradox about learning fear. Because we avoid the things we fear, we can’t learn anything more about them. We can’t learn that the smell no longer leads to a shock unless we take the risk of exploring the dangerous world.

Many mental illnesses, from general anxiety to phobias to posttraumatic-stress syndrome, seem to have their roots in the way we learn to be afraid. We can learn to be afraid so easily and so rigidly that even things that we know aren’t dangerous—the benign spider, the car backfire that sounds like a gunshot—can leave us terrified. Anxious people end up avoiding all the things that just might be scary, and that leads to an increasingly narrow and restricted life and just makes the fear worse. The best treatment is to let people “unlearn” their fears—gradually exposing them to the scary cause and showing them that it doesn’t actually lead to the dangerous effect.

Neuroscientists have explored the biological basis for this learned fear. It involves the coordination between two brain areas. One is the amygdala, an area buried deep in the brain that helps produce the basic emotion of fear, the trembling and heart-pounding. The other is the prefrontal cortex, which is involved in learning, control and planning.

Regina Sullivan and her colleagues at New York University have looked at how rats develop these fear systems. Young rats don’t learn to be fearful the way that older rats do, and their amygdala and prefrontal systems take a while to develop and coordinate. The baby rats “unlearn” fear more easily than the adults, and they may even approach and explore the smell that led to the shock, rather than avoid it.

If the baby rats are periodically separated from their mothers, however, they develop the adult mode of fear and the brain systems that go with it more quickly. This early maturity comes at a cost. Baby rats who are separated from their mothers have more difficulties later on, difficulties that parallel human mental illness.

Dr. Tottenham and her colleagues found a similar pattern in human children. They looked at children who had grown up in orphanages in their first few years of life but then were adopted by caring parents. When they looked at the children’s brains with functional magnetic resonance imaging, they found that, like the rats, these children seemed to develop adultlike “fear circuits” more quickly. Their parents were also more likely to report that the children were anxious. The longer the children had stayed in the orphanages, the more their fear system developed abnormally, and the more anxious they were.

Whenever I read books about daycare, the word “anxiety” is the one that seems to be the most common.

It’s important for the mother to stay at home, and plans should be made before the marriage to make that financially feasible. The plans should start for each parent when they are deciding what the study, where to work, and so on. A working mother who puts her child in daycare will have to exercise extra care to make sure that the child is OK. And this becomes even harder to do when her stress levels go up from work. You can’t bond with a child if you can’t stop screaming obscenities and/or being violent because of work stress.

Another risk factor for anxiety is demanding a lot from a child (say, academically) but not taking the steps to monitor daily progress and provide daily assistance. Think of it as a scale from report-card-day tantrums all the way to daily monitoring and helping with homework. The closer the parents are to the report card day tantrums side of things, the more anxiety if is going to cause the child. Yes, it’s important for children to do well in school so that they can get jobs later. But tantrums don’t achieve anything except to scare them away from learning. Daily monitoring and listening is a better way to create the connection that reduces the child’s anxiety.