Self-licensing

A 2011 study published by researchers in Taiwan indicated that people who take multivitamin pills, especially those who believe that they are receiving significant health benefits from supplement use, are more prone to subsequently engage in unhealthy activities.[12][13][14] Participants in the study were divided into two groups, both of which were given placebo pills; one group was correctly informed that the pills contained no active ingredients and the other group was told that the pills were multivitamin supplements. Survey results showed that participants who thought that they had received a multivitamin were predisposed to smoking more cigarettes and more likely to believe that they were invulnerable to harm, injury, and disease as compared with subjects who knew that they were given a placebo. Participants who believed they were given a multivitamin were also less likely to exercise and to choose healthier food, and had a higher desire to engage in "hedonic activities that involve instant gratification but pose long-term health hazards", such as casual sex, sunbathing, wild parties, and excessive drinking. In the 'multivitamin' group, the more supplements a participant used, the less likely they were to exercise, and smoking was highest among participants who expressed a conscious belief that multivitamins increased health.

The study's authors argued that because dietary supplements are perceived as conferring health advantages, use of such supplements may create an illusory sense of invulnerability that disinhibits unhealthy behaviors. Overall, the study shows that people who take supplements may feel that merely taking a pill is a sufficient contribution to healthy living to enjoy other activities without regard to health, and it exposes a potential hypocrisy among supplement users.[14] The authors advised:

Smokers who take dietary supplements can fool themselves into thinking they are protected against cancer and other diseases. Reminding health conscious smokers that multivitamins don't prevent cancer may help them control their smoking or even encourage them to stop.[16]

Commenting on the implications of the study, Ben Goldacre said:

Believing, incorrectly, that you've done something healthy by taking a vitamin pill makes you more likely to take genuine, concrete, real-world risks with your health. It's a chilling thought, but ideas aren't without impact, and every time we humour a harmless myth – that vitamin pills are healthy, that some fashionable berry prevents cancer – we might be doing more harm than we think.[13]

Researchers Khan and Dhar investigated the influence of self-licensing on consumer decisions regarding the purchase of luxury goods. They reasoned that "relative preferences for a luxury option will be higher if people's prior decisions provide a boost to their relevant self-concept". Due to the self-licensing effect, "a prior intent to be virtuous boosts respondents' self-concepts, thus reducing negative self-attributions associated with the purchase of relative luxuries". Furthermore, they predicted that consumers may be unaware of how their prior decision influences their subsequent choices; i.e. the process underlying the licensing effect may be largely nonconscious.[3] In the study, some participants were first asked to select from a list a charity organizations for which they would willingly volunteer three hours a week. Later, these people—and participants who hadn't been asked to volunteer—were asked whether they would buy designer jeans or an identically priced vacuum cleaner, assuming that they had enough money to buy only one. Participants who were asked to imagine having committed the charitable act before shopping were more than twice as likely to choose the jeans. The authors noted that "People don't even have to do good for this effect to happen ... Even if they plan to do something good, it will give them a boost in their self-image. Any type of situation where you have guilt involved, you will see this, and so this happens in luxury goods."[7][10]

A study by University of Toronto behavioral marketing professor Nina Mazar and Chen-Bo Zhong found that people who bought green products were more likely to cheat and steal than those who bought conventional products.[10][17] The researchers conducted an experiment in which they asked college students to shop for products online from either an eco-friendly or a conventional store. Each subject was then asked to divide a small sum of money between themselves and a stranger in a paradigm known as the dictator game, in which participants can cheat to make more money. The shoppers from the green store were more dishonest than those at the conventional store, which brought them higher earnings in the game. The authors suggested that the results could be accounted for by the licensing effect, noting that "When we engage in a good deed, that gives us a kind of satisfaction. With that self-satisfied feeling can come tacit permission to behave more selfishly next time we have the opportunity". The authors added that "purchasing green products may license indulgence in self-interested and unethical behaviors", and concluded:

We find that mere exposure to green products and the purchase of them lead to markedly different behavioral consequences. In line with the halo associated with green consumerism, people act more altruistically after mere exposure to green than conventional products; however, people act less altruistically and are more likely to cheat and steal after purchasing green products as opposed to conventional products.

Researchers have invoked the self-licensing effect to explain why consumers who opt for energy-efficient products increase their energy usage so as to offset any potential gains. Energy economist Lucas Davis published a study showing that after getting high-efficiency washers, consumers increased clothes washing by nearly 6 percent.[18] Other studies have shown that people leave energy-efficient lights on longer than conventional lights, and that many people who make their homes more energy efficient turn their heating up and ultimately see no reduction in energy costs.[10]

The self-licensing effect was examined by Monin and Miller in a 2001 study which demonstrated that when participants established credentials as non-prejudiced persons, they were more willing to express politically incorrect opinions despite the fact that the audience was unaware of their credentials.[5] Subsequent research by Monin and Daniel Effron showed that an opportunity to endorse Barack Obama during the 2008 presidential election made his supporters more likely to express views that favored Whites at the expense of African-Americans.[19][20] Essentially, the endorsement made people feel like they had shown that they were not biased, giving them a license to subsequently express racially prejudicial views.