More Sugar?

All the students are looking out the window with big smiles on their faces: it's snowing hard and you can hear the whispers throughout the class - "snow day tomorrow!" The excitement of a possible day off tomorrow is palpable. It's a teachable moment.

Let's see a raise of hands: How many of you would prefer a snow day tomorrow knowing that we have to attend an extra day of school in June?

If your students are like ours, most of the hands in class are raised high. Economists call this "discounting the future." Given the choice of a $200 gift today or the same gift in six months, almost anyone would exhibit "time preference" and take the money today. Of course, the assumption is one day of school in March is equal to one day of school in June. Or $200 today is the same as $200 in six months.

Now, let's add a curve.

Let's see a raise of hands: a snow day tomorrow knowing that we have to attend TWO extra days in June?

Or, in monetary terms, $200 today or $300 in six months?

An easy decision?

If most students select the snow day tomorrow or the $200 we might think they lacked self-control. To them, "life is short." We might try to share with them the logic of making a more informed decision. One that comes from age and experience.

Or we might hand out candy bars and ask the question again.

That's what psychological scientists X.T. Wang and Robert D. Dvorak from the University of South Dakota did with their investigation of how blood glucose levels impacted the way test subjects thought about present and future rewards. In their study, Wang and Dvorak used money as the reward and asked volunteers whether they wanted a little now or more later. One group was asked to make the decision after consuming sugar-free snacks and soda. The other group was first given regular (sugar-sweetened) soda and snacks.

The results of the study, as reported in the journal Psychological Science, indicate that student's decision regarding near-term versus later rewards might be influenced by blood glucose levels. Students who had more sugar in their system (as measured by their blood glucose levels) were more likely to forego the lesser monetary reward today for a larger reward later. Students who had less sugar in their system tended to be more likely to "live for today."

As reported by the authors, these findings "are suggestive of an adaptive mechanism linking decision making to metabolic cues, such as blood sugar levels."

One thought is "the results indicate that when we have more energy available (that is, higher levels of blood glucose), we tend to be more future-oriented." The authors note that "the future is more abstract than the present and thus may require more energy to process. Blood glucose as brain fuel would strengthen effortful cognitive processing for future events." Conversely, having low energy (or low blood glucose levels) may make an individual focus more on the present. The finding that a diet soda drink increased the degree of future discounting suggests that artificial sweeteners may alarm the body of imminent caloric crisis, leading to increased impulsivity.

Might there be a behavioral lesson here?

"Johnny, why did you call Steve a name when you know you'd have to serve a detention after school for it?"

For Johnny, getting a laugh from classmates now just might outweigh the discomfort of serving a detention later.

Perhaps if he'd had one of those soft drinks with sugar at lunch.....

And on another front, the Alliance for a Healthier Generation reports an incredible 88% decrease in total beverage calories (sugar) shipped to schools between the first half of the 2004-05 school year and the first half of the 2009-10 school year! One step forward, one step back?