It may be satisfying to think back on good deeds. But beware: studies suggest these rosy recollections can prime us for future behaviors that are actually less ethical. When reassured of our rock-solid morality, it seems, we give ourselves more leeway in ethically slippery situations—a phenomenon dubbed “moral licensing.” In a recent example, California researchers found that individuals who had just written about a past good deed—such as helping a troubled friend or doing charitable work—worked harder for dough from an ethically iffy source.

Authors of the study, published online in April in Social Psychological and Personality Science, asked 140 adults to categorize words in exchange for modest cash rewards, allegedly provided by a store with unethical labor practices. Individuals were not particularly persistent in pursuing raffle prizes from that store, judged by the number of word puzzles they completed to earn raffle entries. The subjects even devalued the purchasing power of the morally tainted currency by underestimating the amount of groceries they could buy with it.

Such concerns went out the window for those reminded of their moral wherewithal: individuals who had recalled a virtuous act completed roughly 40 percent more tasks to earn the supposedly corrupt cash than their less morally reassured counterparts.