Is it true that any habit is formed in 21 days?

A very popular myth is that you can acquire any habit if you repeat an action for 21 days. We checked whether this is indeed the case.

Each of us from time to time thinks that it would be nice to start running in the morning, doing exercises or going to bed early. But how can you make sure that this is not the result of effort, but becomes a habit? They say that to do this you need to repeat a specific action for 21 days, and then we will start doing it automatically. But where did this number come from? And if it's true, why does it take so long to form a habit?

In 1960, plastic surgeon Maxwell Maltz published a book "Psychocybernetics". In it, he talked about his observations of patients and noted that it takes a person at least 21 days to accept a new image of himself - after plastic surgery or amputation of any part of the body. Most likely, this is where the extremely common myth that any habit can be developed in 21 days came from. It is worth noting that Maxwell did not conduct any large-scale research, tests or experiments, he just described his observations. And, most importantly, he believed that people needed “at least” that amount of time. But subsequently, the clarification that this is the minimum possible, and not at all optimal and not exact, period was somehow lost, and this statement gained popularity in the categorical wording about 21 days, during which you can cultivate any habit.

In many books By self-development, articles And posts On social networks, a certain NASA experiment is mentioned on this topic, allegedly confirming the results of the study. The authors write that the astronauts were asked to wear glasses that turned the image visible to the eye upside down. It is stated that 20 participants in the experiment wore these glasses around the clock, and after about three to four weeks, their brains adapted to the inverted image so much that they began to perceive it as normal, without signs of any disorientation. It would seem that this partly confirms the myth of 21 days - but it was not possible to find any official or scientific publications about such an experiment. The only document on the NASA website that is more or less close to what is described is this thesis two researchers from the University of Nevada who actually studied the human brain's perception of upside-down images. However, this experiment was carried out on several university students, and not on astronauts at all, and its results do not contain data on 21 days (or 30 days, or three or four weeks, or all other versions of this myth).

Similar experiment with glasses that reverse the picture visible to the eye, was carried out even earlier, in 1962, by Professor Theodor Erissman from the University of Innsbruck. He put these glasses on his assistant and student Ivo Kohler. At first, it was really uncomfortable for him to even move, but after ten days he became so accustomed to inverted vision that he could easily ride a bicycle without any problems with orientation in space. Scientists made a documentary about this movie. But in this study there is not a word about 21 days.

Anne Graybeal, a neuroscientist at the Massachusetts Institute of Technology, believesthat habit formation is a long and complex process that requires positive reinforcement. And since each person's brain is unique, there is no universal number of days that would be true for each person, even when it comes to the same activity. Some people will need a week to develop a habit - good or bad, while others will need much longer.

In 2009, health psychology researcher Philippa Lally from University College London conducted experiment, who confirmed Graybeel's opinion. 96 volunteers each chose one habit that they had to cultivate within themselves for 12 weeks. Every day they completed their tasks and recorded the results in a diary. Some chose simple actions, such as drinking water with breakfast, while others chose more complex actions, such as regular exercise. As a result, Lalli found that it took subjects between 18 and 254 days to form habits, with an average time of 66 days. That is, yes, for some it really took that same 21 days, but for the majority it took much longer.

Thus, the time that each individual person needs to form a habit is individual and depends both on him (his lifestyle and brain reactions) and on what exactly he is trying to get used to. There are no universal deadlines that would suit everyone, and the very myth about 21 days is uncritically accepted information taken out of context. 

Mostly not true

What do our verdicts mean?

Read on the topic:

1. Maxwell Maltz. Psychocybernetics
2. Is it true that sugar is addictive?
3. Is it true that the habit of cracking your fingers leads to arthrosis?
4. Is it true that the human brain can remember information during sleep?