Why Are Kids Who Get Less Candy Happier On Halloween?

By Shankar Vedantam

Published October 31, 2013 at 3:58 AM EDT

Kids might be more satisfied if they get one good treat instead of one good treat and one lesser treat.

What makes trick-or-treaters happy is candy. And more candy is better, right?

Well, it turns out that might not actually be the case. A few years ago researchers did a study on Halloween night where some trick-or-treaters were given a candy bar, and others were given the candy bar and a piece of bubble gum.

Now, in any rational universe, you would imagine that the kids who got the candy bar and the bubble gum would be happier than the kids who got just the candy bar. George Wolford, a psychologist at Dartmouth College, and his fellow researchers, Amy Doe and Alexander Rupert, found something quite different.

"Those children that got both the full-sized candy bar and the bubble gum second, rated how delighted they were to get these treats lower than those people that got the candy bar only," Wolford says.

To understand what actually is going on we have to go back to the crib, to an earlier study done by Daniel Kahneman at Princeton University, who won the Nobel Prize in economics. Wolford calls it one of his favorite studies in all of psychology.

Kahneman recruited a bunch of doctors to conduct a study among patients getting colonoscopies. Some of the patients got the regular colonoscopy — an uncomfortable, unpleasant procedure. And the others got the same procedure, but at the end of it, the doctors didn't remove the tube from the patients' bodies; they actually left the tube in there a little while longer.

Now again, in any rational world, you would imagine that the patients that got the colonoscopy with the extra discomfort would rate their overall experience as being more painful and more unpleasant. But Kahneman found out that this was actually not the case. The patients who got the extra discomfort actually thought the colonoscopy as a whole went better, and they were more likely to show up for follow-up treatment.

It actually comes down to the order in which these things happen — and that's the connection with the Halloween candy study. In that study, the kids got the great treat first and then a lesser treat afterward.

With the colonoscopies, they got the unpleasant procedure first and then got something slightly less unpleasant afterward. And it turns out that when we think about experiences, we don't think about the experience as a whole — we are significantly biased by how the experience ends.

So if we have a great experience that starts to go downhill, we rate the overall experience as being less good. Whereas if something starts out terribly and then starts to get better toward the end, we rate the overall experience a little bit better. Wolford actually has a theory to explain this.

"If you're in a painful experience and it's getting better, then there's a sense in which things are improving," he says. "So what you're judging is the trajectory. With positive goods, if I'm going from a nice treat to a lesser treat, the trajectory is going the wrong way."

So if you get the lesser treat first and the nicer treat second, you're likely to be very happy; but if you get the nice treat first and the lesser one second, you're likely to be more dissatisfied with the overall experience.