Happy New Year! It’s 2013 and you’ve vowed to cut sweets out of your diet. Despite your desire for a trimmer body, the sight of cupcakes in a café window overpowers your good intentions. You cannot resist the small, sweet reward even though the larger, delayed reward of a healthier body is ultimately more desirable.
What leads some of us to give in to our immediate urges, while others are able to endure the wait for bigger and better outcomes? Neuroeconomists are investigating the brain to answer this question. They are interested in comparing the brain activity of individuals who act impulsively—those who choose rewards now over later—to that of patient folks.
Traditionally, the assumption of researchers in this field, and the related field of behavioral economics, has been that impulsive people choose immediate rewards simply because they dislike waiting. In these prior studies, when presented with a hypothetical choice between, say, $50 now or $100 in a year, impulsive individuals went for the $50. Additionally, they showed a greater brain response to the immediate $50 reward—in the part of the brain that represents how much you are enjoying a reward (the ventral striatum)—than did patient people. Researchers interpreted this brain response as the impulsive individuals’ preference for immediacy. So while impulsive individuals would claim “carpe diem” and “strike while the iron is hot” as their life mantras, the less quoted “carpent tua poma nepotes” and “good things come to those who wait” are patient individuals’ words to live by.
However, impulsivity may not simply be due to how long people are willing to wait for gratification. A recent study by a team of researchers at Washington University in St. Louis found that when people waited for a reward, patient people were seen—through the lens of a functional magnetic resonance imaging (fMRI) machine—imagining the future. In more patient people, the researchers observed increased activity in the region of the brain that helps you think about the future (the anterior prefrontal cortex). The patient individuals, it seems, devoted more energy to imagining receiving their reward later.
What sets this Washington University study apart from previous studies is that researchers have never before focused on the brain responses of individuals after they make a decision and are waiting for their reward. Instead, researchers have typically measured brain activity while people are making their choices. Prior researchers likely disregarded the waiting period because their studies used hypothetical rewards over long delays. Because people weren’t actually waiting in real time to receive a real reward, the researchers could not monitor the brain during this waiting period. This new study presented people with real rewards in the form of squirts of juice either immediately or at a delay of up to a minute. In fact, the researchers squirted the juice straight into the mouths of study subjects, in much the same way that animals have been rewarded in similar studies.
This future thinking, which is associated with the anterior prefrontal cortex (aPFC), has also been found in neuropsychological studies that focus on two different, but related phenomena: prospective memory—remembering to do something in the future, like fill up your gas tank on the way home from work—and episodic future thought—thinking about the future, such as imagining what you’ll cook for dinner later tonight. Now, one more phenomenon can be added to the list of contexts in which people imagine a future outcome and activate their aPFC: imagining future rewards.
One problem with the future is its vagueness. While you are able to imagine in your mind going to the gas station or cooking dinner in general, the exact details of these activities are not clear. You don’t know which pump you’ll use at the gas station, or precisely what time you’ll remove the pizza from the oven. In this way, the future is fuzzy. This fuzziness can make the future less appealing. Remember the marshmallow experiment that tested the willpower of children to resist the temptation to eat a marshmallow placed on a table in front of them, so they could receive two marshmallows after they waited? Research suggests that if that one marshmallow was made more abstract—such as hiding it from view or just showing a picture of it—the reward would become less appealing and more similar in appeal to receiving two marshmallows at a future time. On the flip side, making the future less fuzzy by focusing on the details—eating double the marshmallows currently being presented—could also make the future marshmallows more attractive than the present singular marshmallow. In this way kids would have an easier time resisting the one marshmallow now in exchange for the two marshmallows in the future.
Perhaps a combination of this fuzziness research (i.e., delay of gratification research) with recent neuroeconomics research—linking impulsivity with a lack of future thinking—could be useful for clinicians who are developing treatment plans for impulsive individuals. Because the future is fuzzy and impulsive people have an especially hard time imagining it, clinical treatments could involve de-emphasizing the present, making it more abstract, and building a concrete image of the future. For example, while it may be quicker, easier, and cheaper to buy fast food for dinner—immediate rewards that are all very desirable—people could learn to visualize larger future rewards when deciding what to eat, such as avoiding ailments like obesity and Type-2 diabetes. They could also avoid driving past their favorite fast food restaurants and only stock their cupboards with nutritious foods so the most visually salient meal options are healthy ones. This could help shift the attractive light from being cast on the present desire for fast food to instead being on the future desire for a healthy body.
For impulsive individuals who repeatedly make decisions that satisfy their current desires at the expense of their future needs, the negative effects on their health can be significant. Given the host of public health issues that involve impulsivity, research in neuroeconomics could prove important. Future research could measure the effects of an intervention on the brain. Can we get impulsive people to produce activity in their brain that shows they’re thinking about the future in a concrete way, making them look and act more patiently in the laboratory? Do these interventions lead to real-life choices to invest in the future and not give in to present impulses? Not to mention, could adapting the mindset that the future is worth waiting for help the rest of us keep some of our New Year’s resolutions?
Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.