The Myth of Choice_ Personal Responsibility in a World of Limits - Kent Greenfield [20]
The day of Bryce’s funeral, Balfour was charged with murder. The charge was eventually downgraded to involuntary manslaughter, and a jury acquitted her after a trial. She is now an activist for child car safety, making speeches to other parents around the country. She talks openly about her pain and gives parents tips about how to avoid her fate. One such tip: leave something you will need at work—your purse or briefcase—beside your child’s car seat.5
Why do such horrors occur? How can someone become so distracted that they leave their child to swelter to death in a car? Part of the answer has to do with the way the brain works.
1.
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.”6 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 hard or less familiar stuff. This is why you can arrive at work and remember the news story you heard but not what you saw while you drove. A brain that functions well at both the basic reflexive level and the more sophisticated, analytic level gives us humans an ability to perform at a cognitive echelon unmatched by any other species. We really can multi-task, as long as we’re using different brain structures to do it.
The problem is that the analytic parts of our brains are easily overtaxed, and you cannot dependably ask them to do more than one thing at a time. That is why students who check their email on their laptops while listening to a class lecture are wasting their time and their (or their parents’) money, and it’s why I ban laptops in my classroom. It’s also why having my email inbox open on the screen as I write this chapter is slowing the writing to a crawl.
What’s more, one of the analytic parts—the prefrontal cortex—is also in charge of willpower. So you can exhaust it not only by thinking but also by trying to keep yourself from snacking on a brownie. In one revealing study, people were asked to remember a seven-digit number and then offered a snack. Other test subjects were asked to remember a one-digit number and offered the same snack. Those who were trying to remember the longer series of digits were much more likely to choose chocolate cake over fruit. Remembering the seven-digit number had made the prefrontal cortex less able to restrain itself from choosing the cake.7
One problem with how our brain works is that if the prefrontal cortex is tired or overtaxed or distracted, our basal ganglia take over. I was once driving to Middlebury College to participate in a debate on the First Amendment, and on the stretch of interstate between Boston and central Vermont I tested various riffs I would use on my certainly doomed opponent. My driving brain went on autopilot as my prefrontal cortex devised sophisticated rhetorical punches and my hippocampus attempted to commit them to memory. Meanwhile, I drove thirty miles past my exit. When I realized what I had done, I could not even remember seeing the exit I was supposed to have taken. My damned basal ganglia had completely