Every day, we face thousands of decisions both major and minor — from whether to eat that decadent chocolate cupcake to when to pursue a new romantic relationship or to change careers. How does the brain decide? A new study suggests that it relies on two separate networks to do so: one that determines the overall value — the risk versus reward — of individual choices and another that guides how you ultimately behave.
“Cognitive control and value-based decision-making tasks appear to depend on different brain regions within the prefrontal cortex,” says Jan Glascher, lead author of the study and a visiting associate at theCaliforniaInstitute of Technology in Pasadena, referring to the seat of higher-level reasoning in the brain.
Study co-author Ralph Adolphs, a professor of psychology at Caltech, explains the distinction by way of a grocery shopping example: “Your valuation network is always providing you with information about what’s rewarding around you — the things you want to buy — but also lots of distracting things like junk food and other items popping into your vision off the shelves.”
Cognitive control is what keeps this network in check. “To be able to get to the checkout counter with what you planned, you need to maintain a goal in mind, such as perhaps only buying the salad you needed for dinner,” says Adolphs. “That’s your cognitive control network maintaining an overall goal despite lots of distractions.”
The overall control of impulses is split between the two networks, though they do not counteract each other. When the cognitive control regions are working well, distractions are ignored and behaviors occur in the appropriate context; when valuation is appropriate, choices are made that are likely to be beneficial in the long run. However, says Adolphs, “when either one of them goes offline, impulsive behaviors get stronger and may not be inhibited.”