Does darkness increase dishonesty?:

Yes, it does:

In several experiments, researchers found that light levels influence selfish behavior. People who were placed in a dimly lit room were significantly more likely to cheat than people placed in a well-lit room. Likewise, people who were asked to wear sunglasses were less generous in a sharing game than people who were asked to wear clear glasses. This pattern appears to be the result of an increased sense of anonymity in lower light levels, even though light levels did not confer any actual increase in anonymity.

Zhong, C. et al., “A Good Lamp is the Best Police: Darkness Increases Dishonesty and Self-Interested Behavior,” Psychological Science (forthcoming).

(I'm guessing Congress is actually a lot dimmer than it looks on C-SPAN.)

For more on the subject of deception, check out the work of Paul Ekman.

Related posts:

Here's how much you'll lie to someone the first time you meet them. These two posts will show you how to detect lies.

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