How long does it take to form a habit? That’s a question many people who are keen on transforming themselves and adopting new habits keep on asking. So what is the answer?
In most self-help and motivational literature you will usually find either the number 21 or 30 days. I wanted to find out where these numbers come from.
I got excited when in one piece of literature I found the mention of an old study that was done by NASA. The study that was described was supposed to test the physiological and psychological effects of weightlessness on humans and the resulting spatial disorientation.
Each of the astronauts had to wear convex goggles which flipped their vision of the world 180 degrees, meaning they saw everything upside down. They were supposed to wear these goggles 24/7.
It was a struggle for all of them at first, however after 26 to 30 days something happened to all of the test subjects. Their vision flipped the right side up! They could now see normally even while wearing the goggles.
This was proof that it takes about one month for your brain to rewire and form a new habit. So that’s where the number 30 comes from.
The study is cited in several self-help books, for example by Jack Canfield or John Assarraf. This most likely influenced other people who were creating habit-formation courses and material to put the number of days at 30. Examples of these include: “30 Days to Healthy Eating” by Annie Howell, or “30 Days of Discipline” by Victor Pride, plus many others.
The problem is that this study probably doesn’t exist. I tried searching for this study all over the internet. If this study is so ground-breaking, as it is cited by many self-help gurus, surely it must be all over. Yet, I couldn’t find it.
My guess is that the story evolved into an urban legend from actual experiments that were conducted in the 1950s, but not by NASA. The experiments involved an Austrian professor, Theodor Erismann, strapping upside-down goggles on one of his students, Ivo Kohler, and then observing what would happen.
They even produced a documentary film on these experiments (shown below):
Supposedly, after 10 days, Kohler managed to adjust to his new reality and everything started to seem normal to him and he started to function normally.
I did find a paper about a study on inversion sponsored by NASA (involving students from Nevada, not astronauts), but it had no mention of anything to do with 30 days.
Most likely somehow, in a game of telephone, the research by Kohler and others got bundled up with the number 30 and NASA and ended up serving as a “source” for the statements on habits of many self-help gurus. Unfortunately none of these gurus actually bothered to check the actual research itself. Instead, they just spread the message that they read from another guru, further and further.
So many citations for a non-existing study. Any real scientist would be proud. 🙂
The number 21 also has an interesting history. The source of this number is this little quote by Maxwell Maltz in his book “Psycho-Cybernetics”:
“Invest 30 minutes a day for 21 consecutive days on quiet reflection, working on this with yourself, in solitude.“
The book where this quote comes from is the ultimate source of almost all the modern self-help gurus, from Tony Robbins to Zig Ziglar. The author, Maxwell Maltz, was initially a plastic surgeon who noticed one thing: that many of his patients, even after getting a plastic surgery to get rid of their imperfections, were still unhappy.
He surmised that their root source of unhappiness was internal, deep in the mind. So he set out to combat this by trying to change the mindset of his patients through techniques such as visualizations.
After several years, he ended up writing a book where he summarized his observations and described some of his techniques. Many budding self-help gurus started their careers by reading the book.
In the book, Maltz keeps repeating the number 21 for the number of days people should do the exercises he suggests. One of the self-help gurus probably read that and somehow interpreted it to mean that you can form a habit that sticks after 21 days. This then ended up getting repeated by other gurus and that’s how it became “common knowledge” that you can transform a habit in 21 days.
So you see, these commonly repeated numbers are just self-help bro science. This doesn’t mean that the number and techniques behind that number are ineffective. It just means that they are not backed by scientific research.
However, there is one recent study from 2009 that did look into how long it takes to adopt a habit. The results varied between 18 to 254 days, with the average being 66. The conclusion? It takes a long time to get a habit to be automatic, at least 2 months, but usually more.