If you have ever felt the urge to mug an old lady after buying a package of eco-friendly soap powder, you may not be alone.
According to social science publisher Sage's most downloaded article of 2009-10, going "green" boosts our tendency to lie and steal.
The article, "Do green products make us better people?", was published in the Sage journal Psychological Science. It describes a series of experiments devised by Nina Mazar and Chen-Bo Zhong, both assistant professors in the University of Toronto's School of Management.
Student volunteers were asked to rate products in an online store, with some participants assigned to a store with mostly green products. In a later game, they were asked to share a sum of money with an unseen partner, and those exposed to the green shop offered more.
In another experiment, participants were asked to actually buy products from their respective store. They were then paid a small amount to carry out a short visual perception task, in which the importance of accuracy was stressed.
However, they were also given the opportunity to realise that they could earn more by choosing both the false and the correct answer. They were then trusted to pay themselves from an envelope of money.
The researchers found that those who bought green products were much more likely to give wrong answers and to overpay themselves.
They take this as proof that exposure to green products makes people behave more ethically, but buying them makes us more likely to cheat and lie. They speculate that while exposure to "manifestations of high ethical standards", such as green products, activates "norms of social responsibility and ethical conduct", virtuous behaviour such as buying green products leads to a boost in "moral self-image" that licenses future ethical lapses.
The researchers cite previous studies of the "priming" of social behaviour by environmental cues.
These suggest that looking at pictures of expensive restaurants improves table manners, while exposure to the Apple logo apparently increases creativity.