Hand Washing Leads to Rational Evaluations

Postdecisional dissonance–an extremely close relative of both post-purchase rationalisation and the choice-supportive bias–is the phenomenon whereby once we have made a decision we perceive our chosen option as the most attractive choice and the discarded alternatives as less attractive, regardless of the evidence.

Some intriguing recent research suggests that the physical act of cleaning one’s hands helps us rationally evaluate our past decisions–cleaning our hands cleans our minds, too.

After choosing between two alternatives, people perceive the chosen alternative as more attractive and the rejected alternative as less attractive. This postdecisional dissonance effect was eliminated by cleaning one’s hands. Going beyond prior purification effects in the moral domain, physical cleansing seems to more generally remove past concerns, resulting in a metaphorical “clean slate” effect.

The article is behind the Science paywall but there is an interesting conversation in the comments of Overcoming Bias (via).