The beloved Harry Potter series has enthralled a generation of readers with tales of enchanted elixirs and magical devices, including such things as invisibility cloaks, edible chocolate frogs, talking pictures, and a resurrection stone.  Most of these extraordinary items are purely fantastical, but a few novelties from the series are now available for purchase by Muggles (if you haven’t read the Potter books, that’s you and me).  One such item is a package of Bertie Bott’s Jelly Beans – a small box with uniquely flavored candies, including appealing tastes like blueberry, tutti-fruitti, and marshmallow along with disgusting flavors like ear wax, vomit, dirt, and boogers.

I was not surprised when my adolescent son wanted a box of these jelly beans, as I assumed he was going to prank his siblings and get them to unwittingly eat the beans and risk a booger-flavored encounter.  I was stunned, though, when instead he immediately opened the box and began taste testing them himself – knowing that he was going to sample some repulsive flavors.  Why in the world would anyone knowingly and voluntarily subject themselves to something so unpleasant?

New research by Christopher Hsee and Bowen Ruan suggests a simple answer to this question:  Curiosity.  It is human nature to seek out information, to dig for details, to get the facts and know the outcomes. The power of curiosity can be seen in our obsession with social media like Facebook and Twitter, with the success of gossip magazines like People, and with the effectiveness of season-ending cliff hangers for television series that want you to tune back in next fall. But just how powerful is curiosity?  Could it truly motivate us to willingly experience pain without any gain?  Hsee and Ruan think so.  They argue that the desire to resolve uncertainty – to know which jelly beans are offensive and whether they do in fact taste like vomit or ear wax – is so powerful that individuals will knowingly subject themselves to unpleasant outcomes in order to find the answers.

Hsee and Ruan refer to this willingness to experience a negative outcome for the sake of satisfying curiosity as the Pandora effect.  In the classic mythological tale, Pandora was given a box and was warned never to open it.  She did so anyway, releasing all the evils of the world.  History is full of similar cautionary tales about curiosity, like Adam and Eve, who wanted a taste of the forbidden apple, and Lot’s wife, who wanted one last look at the condemned city of Sodom.  Even young children learn about the perils of curiosity through the mischievous stories of a monkey named George.  Despite these warnings, curiosity propels humans to engage in risky behavior with potentially devastating consequences, including exploring treacherous terrains, sampling illicit substances, gambling at casinos, or even reading text messages while driving. 

Not everyone hikes Mt. Everest or plays the roulette wheel, however, so Hsee and Ruan conducted a series of experiments to assess whether average people would expose themselves to aversive stimuli for no apparent benefits, other than to satisfy their own curiosities. In their first study, participants were seated in a waiting room when they arrived for the study.  While they ostensibly waited for the real study to begin, they were told that they could, if they so chose, amuse themselves with novelty pens on the table.  For half of the participants (certain-outcome condition), the pens had either a green dot (indicating a regular pen) or a red dot (indicating a trick pen that would deliver a shock if clicked).  For the other participants (uncertain-outcome condition), all the pens had a yellow dot, indicating that each pen could be a trick pen or a regular pen. Regardless of condition, participants were free to click (or not to click) any pen on the table while they waited.

One might expect that participants would click more of the pens in the certain-outcome condition, as participants could choose to click the green pens that that were certain not to shock them (to kill time), to click the red pens that were certain to shock them (if they wanted to know what the shock felt like), or some combination of the two.  In the uncertain-outcome condition, participants ran the risk of getting shocked with every single pen click.   Despite the increased risk for negative consequences, participants clicked significantly more pens in the uncertain-outcome condition (51%) than in the certain-outcome condition (30%).

Perhaps participants merely clicked the pens because they were bored, or they somehow felt obligated to click a few pens for the sake of the study.  While these explanations might account for the fact that participants in both conditions clicked some of the pens, they cannot account for the fact that participants clicked more pens in the uncertain-outcome than the certain-outcome condition.  It is possible, though, that the higher response rate for the uncertain-outcome condition reflects a statistical artifact of participants' desire to sample both the regular pens and the trick pens.  Statistically speaking, it would take more clicks to sample both pen types in the uncertain condition than in the certain condition.

To control for this possibility, Hsee and Ruan conducted a second study in which all participants had the opportunity to click 10 pens with green dots, 10 pens with red dots, and 10 pens with yellow dots.  If participants wanted to experience one pen of each type, they could simply click one red and one green pen and be done.  Alternatively, if participants simply elected to click a few pens at random, they had a two-thirds chance of selecting a certain-outcome (red or green dot) pen.  Both of these options suggest higher response rates for the certain-outcome condition.  The data, however, reflect a very different pattern.  Participants clicked 42% of the pens in the uncertain condition, and only 14% of the pens in the certain condition.  Clearly, participants were curious about those yellow pens.

It is important to note that the studies by Hsee and Ruan focused exclusively on cases in which curiosity led to negative or neutral outcomes, and it is most certainly the case that curiosity has historically propelled positive and important discoveries, exploration, and personal growth.  When outcomes are positive (e.g., opening a present), entertaining (e.g., celebrity romances), or even simply informative (e.g., the results of medical tests), it is easy to understand the value and power of curiosity.  These findings highlight the fact that curiosity may also drive behavior even when negative outcomes are expected and there is no redeeming value in the knowledge.  The drive to know the unknown is great.  My son sampled the potentially repulsive jelly beans for the same reason that other people gawk at the site of a car accident or spy on their lovers.  Like them, he was curious.  And yes, he experienced some very aversive consequences as a result of his curiosity, because there are in fact some very nasty beans in the Bertie Bott’s box.  How do I know?  I was curious too, and I was rewarded with the lingering flavor of boogers in my mouth.