Pop quiz: You need $20 for lunch and can only ask one person for a loan.
Do you ask a) the eco-conscious vegetarian who only buys green cleaning products, or b) the Hummer-driving meathead who says Al Gore is overrated.
If you choose person A - assuming she cares as much for fellow human beings as she does for the planet - you could end up hungry.
Green consumers are more likely to steal, lie and hoard their money compared with those who are exposed to environmentally friendly products but don't buy them, according a new study by University of Toronto researchers to be published in the journal Psychological Science.
"Green products do not necessarily make us better people," wrote co-researchers Nina Mazar and Chen-Bo Zhong of the University of Toronto's Rotman School of Management.
The researchers theorize that the effect stems from a "licence" phenomenon: When people do something right, they feel it gives them the licence to act unethically in other areas.
To reach these conclusions, the researchers asked 150 students to participate in laboratory games. One experiment showed that participants who were merely exposed to products from a green store shared more money with others compared with participants who purchased the items. Another experiment revealed that the green consumers were more likely to lie or steal in order to make money.
"This was not done to point the finger at consumers who buy green products," said Ms. Mazar, a marketing professor at Rotman and a green consumer.
But, she said, buying green "doesn't necessarily mean we will be morally better in other things as well."