09/29/2011 09:04 pm ET | Updated Nov 29, 2011

When Kids Are Left in Cars: Blame the Brain

This month's worst news item here in Boston was that of a toddler, Gabriel Josh-Cazir Pierre, dying after being left in a daycare van. Such stories bring dread to any parent. As a parent of a child near the same age as Gabriel, I can imagine -- if only faintly -- the profound grief of his mother and family.

As the facts begin to be sorted out, it appears that the van driver failed to notice that Gabriel was still on board at the end of the morning route, leaving him unattended in what would quickly become a sweltering vehicle. The family is mourning, and state regulators are discussing how best to respond. Meanwhile, it is easy to rush to judgment of the van driver. The normal reaction to such a tragedy is to wonder aloud: Who could forget a child?

The honest answer, unfortunately, is that I could. You could too.

Such a dreadful mistake is not as uncommon as you might think -- children die after being left in cars about 40 times a year in the United States, and usually it's a parent who does the forgetting. Typically, a few circumstances conspire together to increase the risk of such an occurrence. The parent is tired and distracted and stressed; there is a change in routine; and there is some kind of breakdown in precaution or preventative stopgap. Often, children are forgotten when they are being carted to school or daycare by a parent who does not usually do that parental chore. If the child falls asleep and the parent gets distracted, it is easy for the parent to go on "autopilot" and let the usual routine take over. The parent goes to work and the child is left in the car.

Such mistakes are gut-wrenching and perhaps inexcusable. But they are not incomprehensible, especially the more we understand how the brain works.

Our brains comprise a number of different structures, some highly evolved, nimble, and sophisticated, others much more primitive. At the top of the evolutionary brain heap are the prefrontal cortex, which thinks and analyzes, and the hippocampus, which creates and stores new memories. More basic are the basal ganglia, which control actions that are voluntary but barely conscious. This portion of our brain is so primitive that it is not very different from what a reptile has.

Usually, these various components work like a finely tuned Ferrari. The prefrontal cortex takes care of the conversation you're having on your cell phone with your spouse or friend while the basal ganglia control the familiar, routine task of driving the car, guiding your feet down the sidewalk, or whisking the scrambled eggs. Your basal ganglia can put you on autopilot for the basic stuff, while the more highly evolved parts of your brain work on the difficult or less familiar. This is why you can drive to work and later remember the news story you heard but have no memory of the drive itself.

One problem with how our brain works is that if the prefrontal cortex is tired or overtaxed or distracted, our basal ganglia take over. According to experts, this "autopilot" feature of the basal ganglia is responsible for many of the forgotten baby cases. If a parent is suffering from lack of sleep, stress or distractions (and what parent doesn't?) the higher-functioning parts of the brain become more susceptible to bullying by the basal ganglia, which take over and put you on autopilot. As psychology professor Gary Marcus explains, "When we are stressed, tired, or distracted, our deliberative system tends to be the first thing to go, leaving us at the mercy of our lower-tech reflexive system -- just when we might need our deliberative system the most."

If you have ever put your dry cleaning in your car on the way to work and forgotten to drop it off, or been asked to stop on your way home to buy a gallon of milk and not done it, then you have felt the power of the basal ganglia autopilot. And, the experts say, if you can forget your dry cleaning or a gallon of milk, you can forget your child.

I have never forgotten my child in the back of the car, or at school, or at a friend's house. But I understand how it could happen, and I bet most parents can, too. So as I think about the parents of little Gabriel, and indeed of the van driver, I think: "There but for the grace of God go I."