The “marshmallow test” became one of the best-known of all the scientific studies I wrote about in Emotional Intelligence; it was featured on 20/20, Oprah, and the Lehrer Report, as well as Time magazine. In this experiment four-year-olds from the Stanford University pre-school were brought to a room and sat in a chair in front of a juicy marshmallow on a table. The experimenter then told them they could eat it now, or get two if they were willing to wait until the experimenter came back from running an errand.

Now we have a better idea of exactly what part of those four-year-old brains was at work in resisting temptation or giving in. An article published August 22 in the Journal of Neuroscience [Marcel Brass at al., vol 27: pp 9141-9145] has pinpointed the brain area responsible for such feats of self-control. Whenever we get an impulse to do something, but then don’t act on it, we can thank – the dorsal fronto-median cortex — an area just above and between the eyes.

A failure in this circuitry may be at play, the researchers suspect, in disorders ranging from attention deficit to addictions. In the marshmallow test, impulse control turned out to predict how well those kids were doing 14 years later, as they were graduating high school. Those who waited, compared to those who grabbed, were more popular with their peers, had less trouble delaying gratification, and scored far higher on achievement tests.

These prefrontal circuits are among the last part of the brain to become anatomically mature; much of the increasing self-control that mark a child’s maturation over the years are the external signs that these circuits are developing as they should.

For instance, the “Terrible Twos” refers to the daily child-parent drama of impulse and its control which no doubt revolves around this circuitry. As a toddler lunges for the fragile lamp, dog’s food, paring knife — you name it – a parent’s firm “No” stands in for a fully functioning dorsal fronto-median cortex. As that circuitry matures, the “no” becomes internalized, a basis for free will, some say – or, more specifically, “free won’t,” the capacity to squelch an impulse.

By their very nature impulses come unexpectedly and unbidden, from the mind’s unconscious. But once they come, we have choice: to act on the impulse or not. The capacity to “just say no” to dangerous impulses is one mark of emotional intelligence. That’s the point of the Stoplight” in school lessons in social/emotional learning, where posters on school room walls remind kids, that when they get upset, they should remember:

• Red light – stop, calm down, and think before you act.
• Yellow light – think of a range of things you should do (not just your first impulse)
• Green light – pick the best one and try it out.

Or, as the emotions expert Paul Ekman put it when I taped a conversation with him recently [www.morethansound.net], one of the key goals of psychotherapy is to “increase the gap between impulse and action.” It’s in that gap that our free won’t keeps us out of trouble.