By Alex Fradera

Changing an unhealthy habit depends a lot on your belief that you can do it, something psychologists call self-efficacy. Take smoking, for example. Your belief that you are capable of quitting will influence the likelihood you will decide to quit in the first place, the amount your smoking reduces, and your chances of staying smoke-free in the long-term.

This self-belief doesn’t come out of nowhere. Besides seeing ourselves make progress (called “mastery”), health psychologists will tell you that one of the most important inspirations is seeing others successfully make the changes that you desire. To test how true this is, Lisa Warner from the Freie Universität Berlin and her colleagues looked at the impact on smokers of having a partner whose own attempt to quit is going well. Their findings, published in the British Journal of Health Psychology, didn’t fit the expected pattern – but there’s news that co-quitting couples can help each other make a difference.

Warner’s team asked 85 couples, made up of partners who had chosen to quit together, to keep a diary of their progress. At the end of each day, every participant recorded whether they had smoked any cigarettes that day (to indicate their mastery) and also their feelings of self-efficacy regarding the challenge of quitting, rating their agreement with items such as “I am confident that I can refrain from smoking tomorrow even if it is difficult”. The researchers expected that when one partner improved their mastery, this should boost their other half’s self-efficacy the next day.

This isn’t quite what the researchers found, but partners certainly mattered. The day-by-day analysis showed that a participant’s self-efficacy was more likely to go up when their partner had shown increases in their own self-efficacy the day before. So partner confidence was contagious. The same was true for mastery: one partner’s success predicted their other half’s next-day success (or another way to see this: when one person gave in, it was more likely that their partner would succumb on the next day). Intriguingly, however, partner mastery didn’t seem to affect a participant’s next-day self-efficacy.

The fact that witnessing success in a close other wasn’t a driver of self-efficacy is a puzzle for the researchers, but overall this is still important news for couples trying to make healthy changes together – one way or another, a determined partner can be a source of support for finding your way out of smoking – a habit that kills around six million people a year. So put your mind to it, lean into that success cycle, and know that your efforts are feeding those of the person you love.

—Day-to-day mastery and self-efficacy changes during a smoking quit attempt: Two studies

Alex Fradera (@alexfradera) is Staff Writer at BPS Research Digest