Each new year brings its share of good resolutions: return to sport, eat a more balanced diet, spend less time on screens… And according to a theory spread for decades, it would take 21 days for these new habits to become automatic and anchor sustainably in our daily lives. But is this really the case?
The magic deadline of 21 days to change a habit called into question
The origins of this theory date back to the 1960s, when American plastic surgeon Maxwell Maltz hypothesized that his patients needed at least 21 days to get used to their new appearance and create a “different mental image”. ” of themselves. This observation appears in his famous work “Psycho-Cybernetics”, which has become a bestseller and a reference in the world of well-being.
Sixty years later, experts are questioning this 21-day theory. A study conducted by researcher Phillippa Lally of University College London in 2009 revealed that a new habit takes an average of 66 days to become automatic. This time frame can vary greatly depending on the person or circumstances, ranging from 18 to 254 days.
According to Phillippa Lally, it’s difficult to predict how these time frames will vary, but she suggests that it’s probably easier to consider a habit automatic when it’s simple. Drinking a glass of water in the morning takes less effort than starting to exercise regularly, for example, which may make it seem like the first habit is taking hold more quickly than the second.
It all depends on the habit to integrate into your daily life…
A notion which was confirmed in a study published in January 2023 in the journal PNAS. “Contrary to popular belief that there is a ‘magic number’ of days to develop a habit, we find that it typically takes months to form a habit of going to the gym, but weeks to take habit of washing hands in hospital“, write the authors.
Their study was based on data from 30,000 people practicing physical training and 3,000 hospital employees. After examining twelve million exercise sessions and more than forty million hand washings, scientists determined that it takes an average of six months to form the habit of exercising, while establishing the habit of washing hands was usually counted during the week.
Good in his body, good in his head!
What solution to really keep your good resolutions?
Thomas Boraud, director of neuroscience research at the CNRS and head of the Institute of Neurodegenerative Diseases in Bordeaux, confirms this notion by explaining the mechanism of habit. “The age of the habit makes it more difficult to stop. And the older you are, the more complicated it is to get rid of certain behaviors. The personality of the individual also plays a role. We are not equal, some are more sensitive to change than others”, he explains in an interview with the media Ouest Europe. For him, establishing an average duration for successfully adopting a new behavior, or abandoning an old habit, would be “wishful thinking”.
So, in this new year, as we strive to say goodbye to our bad habits, it is important to keep in mind that the path to change can be longer than the famous 21 days, and that it depends of various individual factors. But rest assured there are solutions to achieve these goals in the long term. In this specific case, researcher Lally advises only adopting habits that you really want to integrate into your life.