There is an oft-quoted time frame that’s become accepted in many self-help circles, and among those coaching others to make changes in their lives. We hear over and over again that for something to take root and become habitual requires a minimum of three weeks, 21 days, or something longer—like a month. Where did this come from?

One never knows for sure, but the interwebs coughed up the name Maxwell Maltz.

In the preface to his 1960 book Pycho-Cybernetics, Maltz (a plastic surgeon turned psychologist) wrote about how “it usually requires a minimum of 21 days to effect any perceptual change in mental image” following plastic surgery to get “used to a new face.” Apparently, when an arm or a leg are amputated, the “phantom limb” can persist for about 21 days, also.

Dr. Maltz highlighted a number of other phenomena that clock-in around 21 days, or three weeks, to take root.

James Last, a writer focused on “behavioral psychology, habit formation, and performance Improvement” mentions that it was Maltz’s book that influenced a host of self-help gurus, from Zig Ziglar to Tony Robbins. Last equates it to that game we played when we were kids, “Telephone”—where a story gets started and by the end, Maltz’s “a minimum of 21 days” has now been turned into a gospel aphorism that “it takes 21 days to form a new habit.” Continue reading →