The effect has been shown to last more than six months after questioning. “If you question a person about performing a future behaviour, the likelihood of that behaviour happening will change,” said study co-author Dave Sprott, senior associate dean of Carson College of Business, Washington State University.

The basic idea is that when people are asked “Will you recycle?” it causes a psychological response that can influence their behaviour when they get a chance to recycle. The question reminds them that recycling is good for the environment but may also make them feel uncomfortable if they are not recycling. Thus, they become motivated to recycle to alleviate their feelings of discomfort.

Overall, the researchers’ findings suggest questioning is a relatively simple yet effective technique to produce consistent, significant changes across a wide domain of behaviours. The study appeared in the Journal of Consumer Psychology.