The secret to keeping a New Year resolution is to ask, rather than tell, yourself to change your behaviour, research suggests.
Scientists have found that a simple question such as "will you exercise this year?" gets better results than declaring "I will exercise".
The thinking is that when we are asked such a question it causes a psychological response that can influence us in future.
The question reminds us that exercising is good for us, but may also make us feel uncomfortable if we are not exercising, so boosting our motivation.
The study, published in the Journal of Consumer Psychology, pooled data from more than 100 studies over the past 40 years examining a phenomenon known as "question-behaviour effect" in which asking people about performing an activity influences whether they do it in the future.
The effect has been shown to last more than six months after questioning.
Dr Eric Spangenberg, of the University of California Irvine, said:
"We found the effect is strongest when questions are used to encourage behaviour with personal and socially accepted norms, such as eating healthy foods or volunteering."
Researchers say the finding could have far reaching implications for campaigns encouraging us to recycle or not to drink and drive.