A study published in Psychological Science, a journal of the Association for Psychological Science says, dim lighting and sunglasses can encourage dishonest and unethical behavior.
To reach the conclusion, psychological scientists Chen-Bo Zhong, Vanessa K. Bohns (both of University of Toronto's Rotman School of Management), and Francesca Gino (University of North Carolina at Chapel Hill) conducted three experiments to test whether darkness can license dishonest and self-interested behaviors.
In the first experiment, participants were placed in a dimly or well-lit room and received a brown envelope that contained 10 dollars along with one empty white envelope. They were then asked to complete a worksheet with 20 matrices, each consisting of 12 three-digit numbers. The participants had five minutes to find two numbers in each matrix that added up to 10. The researchers left it up to the participants to score their own work and for each pair of numbers correctly identified they could keep 0.50 dollars from their supply of money. At the end of the experiment, the participants were asked to place the remainder of their money into the white envelope on their way out. While there was no difference in actual performance, participants in the slightly dim room cheated more and thus earned more undeserved money than those in a well-lit room.
In the second experiment, some participants wore a pair of sunglasses and others wore clear glasses while interacting with an ostensible stranger in a different room (in actuality participants interacted with the experimenter). Each person had $6 to allocate between him-or herself and the recipient and could keep what he or she didn't offer.
Participants wearing sunglasses behaved more selfishly by giving significantly less than those wearing clear glasses.
In the third experiment, the scientists replicated the previous experiment and then measured the extent to which participants felt anonymous during the experiment. Once again, those wearing sunglasses gave significantly less money and furthermore, those wearing sunglasses reported feeling more anonymous during the study.
Across all three experiments, darkness had no bearing on actual anonymity, yet it still increased morally questionable behaviors.
The researchers suggest that the experience of darkness may induce a sense of anonymity that is disproportionate from actual anonymity in a given situation.
Zhong explains, "Imagine that a person alone in a closed room is deciding whether to lie to a total stranger in an email. Clearly, whether the room is well-lit or not would not affect the person's ctual level of anonymity. Nevertheless, darkness may license unethical behavior in such situations."