We craft haunted houses and scary decorations to evoke particular emotions. We choose our costumes to reflect something about the kinds of people we are or want to be — edgy, sexy, funny, clever. For children, Halloween is an experiment in delayed gratification and negotiation — which candies to eat now, which to trade, which to save. It's no surprise, then, that Halloween might reveal interesting features of human psychology.
But you might be surprised by just what we can learn.
In fact, there's a long tradition of using Halloween to shed light on the human mind and behavior. Consider three examples of clever studies that use this yearly event to uncover features of human morality, belief and allegiance.
In a study published in 1976, researchers observed over 1,000 trick-or-treating children as they visited houses in Seattle on the evening of Halloween. The researchers were interested in understanding the conditions that lead to "uninhibited" behavior: in this case, stealing Halloween candy or money. One of the variables they manipulated was whether the adult who greeted the children at the entrance to a house asked for each child's name and address, thereby treating each child as an identifiable individual, or instead let each child remain anonymous. Either way, the adult then instructed each child to take one candy from the table while the adult went away to "work in another room."
Unbeknownst to the children, their behavior was recorded by an observer behind a peephole. For each child, the observer recorded how many candies were taken, as well as whether the child took any money from a bowl of coins next to the candy. And take candy and money they did: About 30 percent of children took extra candy, money or both.
The researchers identified several factors that influenced the probability that a child would steal candy or money. Thefts were more likely for children who remained anonymous, who were in groups rather than alone, and who were not accompanied by an adult. There was also an important influence of peer behavior: Kids in groups were more likely to steal if the first child in their group did so.
And so it is that the simple pleasures of trick-or-treating can reveal something about the conditions that support bad behavior.
Almost three decades later, in a study published in 2004, three psychologists used Halloween to better understand how children differentiate fantasy from reality. In the study, 44 children heard about the Candy Witch at their child care center just before Halloween. The children were told that when invited to do so, the Candy Witch visits a house after Halloween to swap candy for a toy.
Half the children also received "evidence" for the existence of the Candy Witch. They "overheard" their parents call the Candy Witch to arrange a toy swap — and the next morning they found that some of their candy had been replaced with a toy.
Overall, 66 percent of the children claimed that the Candy Witch was real just after Halloween, with younger children (mostly 3-year-olds) no more likely to do so than older children (mostly 4- and 5-year-olds). However, the older children were more sensitive to the presence or absence of evidence: Those who received evidence were often fooled; those who did not were more skeptical.
These findings challenge the idea that children are indiscriminately gullible. Levels of belief were quite high, but many children were never fooled, and the older children were appropriately influenced by the presence or absence additional evidence.
As a final example, consider a paper published earlier this year in which two economists reported the results of Halloween experiments used to assess children's political preferences before the 2008 and 2012 presidential elections. To do so, they set up two candy tables at a house in a liberal neighborhood of New Haven that attracts many trick-or-treaters. One table was decorated with Obama campaign props; the other with campaign props for either McCain (in 2008) or Romney (in 2012).
When children arrived to trick-or-treat, they were given one of two choices. Half the children were told that they could go to the Obama table or to the McCain/Romney table and that they would receive the same amount of candy at each table. The other half were told that they would receive twice as much candy at the McCain/Romney table. The researchers were interested in how children would choose in the first case, but also whether extra candy would be enough to sway their choice.
In both years and in both cases, a majority of the 479 participants chose the Obama table. In 2008, 78 percent of children chose the Obama table when the candy payouts were equivalent, and 71 percent did so even when the McCain table offered more candy. In 2012, 82 percent chose the Obama table when the payouts were equivalent, and 78 percent did so even when the Romney table offered more candy.
These results suggest a pretty robust political preference, even among young children (some as young as 4). They also suggest that a candy incentive wasn't enough for most children to switch their preference. Interestingly, though, the older children (9 and older) were more willing to shift their choice for greater candy. It's unclear whether this reflected a weaker political preference or a better appreciation for the extra value of the candy, and the otherwise relatively inconsequential nature of the table choice.
Fast-forwarding to this election cycle, the findings suggest that even young children are likely to be feeling the power of political allegiances in their homes and communities, and that even a symbolic gesture (which table to choose) has personal value — at least the value of one or two pieces of Halloween candy.
These three examples of Halloween research — and they aren't the only ones out there — suggest some clever ways in which we can learn about human psychology from this yearly tradition. They also put a new spin on the "trick" in trick-or-treat — you might just think twice about what's governing your choices and beliefs this Halloween, just in case the trick's on you.
Tania Lombrozo is a psychology professor at the University of California, Berkeley. She writes about psychology, cognitive science and philosophy, with occasional forays into parenting and veganism. You can keep up with more of what she is thinking on Twitter: @TaniaLombrozo