Habit myth #3: Habits take 21 days to make or break

Sometimes I think that the two most meaningless words in the English language are “Studies show….”

Don’t get me wrong—I think research into how the brain transforms actions into habit is fascinating and important. But not everyone who’s interested in habit formation wants read the actual studies—including, it would seem, many of the people who write articles and blog posts based on them. As a result, we have a lot of myths floating around cyberspace. The 21-day concept is a prime example.

Ever wonder where it came from?

In 1960, American cosmetic surgeon Maxwell Maltz published Psycho-Cybernetics, a bestselling self-help book about improving self-image. In it, he observed that it took an average of 21 days for an amputee’s self-image to adjust to the loss of a limb. Self-help writers who were influenced Maltz’s work expanded the 21-day framework to include other major life changes. This was repeated by the next round of writers, and so on until it became one of those things that “everybody knows” about making and breaking habits.

You may also have heard that no, the REAL number is 66 days! Because studies show it!

This idea originated with a paper by Phillippa Lally, published in the European Journal of Social Psychology in 2010. Lally, a doctoral candidate at the time, enlisted 96 undergrads for a 12-week study. Each chose a single habit involving eating, drinking, or physical activity. Of the participants, 82 recorded enough data for analysis. A mathematical model was created to reflect the rate at which these students achieved “automaticity,” which is the neuroscientist’s word for “a habit.” The model fit 62 of the participants, of whom 39 were considered a “good fit.” From this small sample, Lally determined that the range of habit formation was 18-254 days, with 66 being the average. Keep in mind that the study lasted only 84 days, so these numbers are based on a mathematical projection—one that was a good fit for only 39 out of 96 participants. It’s an interesting study that raises good questions, but “What is the new Magic Number of habit acquisition?” is not one of those questions.

Some actions become habitual in a few days, others might require months before they become automatic. Don’t get discouraged if you don’t acquire a habit as quickly as someone insists that you “should.” Focus on what you need to do today, and let the process happen in its own time.