There has always been a correlation between how ethically people behave and how brightly their surroundings are lit; most evil deeds are done under cover of darkness.
A new study suggest that this is not only because of the threat of discovery. Researchers 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.
When the researchers collected the envelopes and reviewed the results at the end of the five-minute period, what they found was striking. Consistently, the people in the dimmer room reported finding more matches than those in the bright room. When their work was checked, it turned out that cheating was rife in the dim room. The darkness seemed to confer what the researchers called a "false sense of concealment." Two other experiments by the same researchers had similar results.