Why Shady Deeds Are More Likely to Happen in the Dark

Human beings can be a devious lot. At some point, even the most moral of us have skulked or sneaked or filched something we weren’t supposed to — even if it were just a cookie from the kitchen. Of all the things that get our sneakiness juices going, there is nothing like a little darkness.

There has always been a correlation between how ethically we behave and how brightly our surroundings are lit — most evil deeds are done under cover of darkness, and the rarest and most brazen crimes are those committed in broad daylight — not least because we’re less likely to be caught in the act after nightfall. But in a new study published in the journal Psychological Science, psychologists Chen-Bo Zhong and Vanessa Bohns of the University of Toronto and Francesca Gino of the University of North Carolina suggest that it’s not only about the threat of discovery. There are other reasons darkness gives us a waiver to misbehave.

The investigators already knew that throughout our lives, we have a sometimes distorted sense of the ability of darkness to conceal. Toddlers cover their eyes when they’re playing hide and seek in the belief that if they can’t see you, you can’t see them. In his famed 1969 experiments on human moral behavior, Stanford University psychologist Philip Zimbardo found that if subjects were wearing dark hoods and baggy clothes, they were more inclined to administer electric shocks to other volunteers than they otherwise would be.

In the new study, Zhong and his colleagues took a subtler approach, but one that’s likely to have more real-world implications. In the first part of their three-part experiment, they recruited 84 students and divided them between a brightly lit room with 10 fluorescent bulbs burning and a dimmer room with only four bulbs. The subjects were each given a brown envelope with $10 in singles and coins as well as an empty white envelope. They were all then told they had five minutes to complete a simple mathematical task, looking for pairs of numbers that added up to 10 in a grid of three-digit numbers. They could keep 50 cents for every pair they found and were to put the leftover money in the brown envelope.  Read Article

By Jeffrey Kluger