How long does it take to create a habit?

(CNN) — When making your New Year's resolutions, you may think that it takes 21 days of repeating an action for it to become a habit. So I decided to go to the gym for 21 days, thinking that on the 22nd, going to the gym would be automatic, even fun. It may be difficult to think about going to the gym for an entire year, but 21 days is possible.

We're sorry to disappoint you, but this estimate of 21 days is not correct. According to customs expert W Destroyer of myths Wendy Wood, This lie comes from a self-help book from the 1960s and actually describes the time it takes to get used to your new look after plastic surgery.

How long does it take to form a habit? It's a question many of us want answered in those difficult first days of habit building. When will I floss every morning without having to think about it? When will I stop needing reminders to take my medication? When will it be easier for me to go to the gym?

Unfortunately, Our latest research They showed that there is no magic number.

So what are we supposed to do? We know that people with established habits need to rely less on willpower to implement good behaviors, but the first few days of implementing good behavior often seem like a struggle for everyone. Only after consistent repetition will the desired behavior seem easier.

We've found some practical, science-based tips that can help you reach your goal faster.

We used machine learning, a type of artificial intelligence, to analyze data from tens of thousands of gym-goers and hospital workers in North America in hopes of better understanding how two important habits are formed: habits related to exercise and hand-washing. Habits.

We define habit as the point at which behavior becomes highly predictable for a given person using our statistical modeling tools.

Here's what we learned that might be useful to you:

1. Simpler habits form faster

We'd all like to believe that exercising or doing another challenging new activity will become automatic within three weeks. However, in our research we have found indications that the speed of habit formation may be related to the complexity of the habit we are trying to create.

For example, washing your hands. Although everyone is different, people usually get used to washing their hands within a week or two, while getting used to going to the gym usually takes months. In our study, we only looked at the formation of two types of habits, but we suspect that simple habits like washing your hands or brushing your teeth may become habitual faster than the old 21-day myth suggests.

Why does it take months and not weeks to get used to going to the gym? In our study we only compared two habits, but our hypothesis is that the complexity of going to the gym slows down habit formation. Going to the gym takes a lot of time, effort, and planning. At best, it's a daily habit, making it less frequent than, say, washing your hands. Overall, previous research suggests that a higher number of repetitions is key to creating habits.

What does this mean for you? If you're starting a “couch to 5K” training plan, don't beat yourself up if you don't put on your running shoes without thinking about it by week four. It will likely take several months before your workouts become automatic. A good dose of patience will come in handy.

If you want to build a physical activity habit more quickly, consider trying a faster form of exercise — for example, doing some jumping jacks or squats — and do it every hour. This way, the new habit will be put on autopilot in less time.

2. Create situations conducive to this habit

It's common to think that creating healthy habits depends on willpower, but habit researchers (including our team) don't recommend “forcing” yourself to create a habit. Instead, we encourage you to focus on creating habit-reinforcing situations, that is, environments that ultimately “encourage” the desired behavior.

Cues can be elements of your physical environment, time of day, specific objects, or even people you meet. For example, seeing the digital clock in the bathroom that says “6:30 AM” might prompt you to brush your teeth if you always do so at that time.

Previous studies suggest that thinking about when and where you will achieve a goal is critical to successful habit formation. We've also seen good results using twisted signals to stimulate people's memories. So, if you want to start going to the gym, our studies and other people's studies suggest that it's best to plan out the day of the week you want to go and perhaps add a unique cue, like an alarm on your phone. By Olivia Newton-John Every time you have to go to the gym.

But don't despair if you don't find the right signs right away. In the early days of forming any habit, you should plan for an exploration phase, as some parts of what you are trying to put on autopilot will be new and you will have to learn how to incorporate them into your daily life.

He deserves. We found that the longer we monitored someone, the more predictable their exercise (or hand-washing) patterns became. After a period of experimentation and repetition, you can end up creating predictable habits.

3. Habits make us less flexible

The dark side of habits is that, once we form them, we reflexively practice them even if it is not the best choice. If you chose fruit instead of a muffin every morning, you would probably realize that the apple was bad. But if you take it on a plane, you might discover it's spoiled after you walk out the door and take your first bite on your way to work. disgusting!

Is this danger real? Do we respond less to information indicating that we should or should not continue an activity or choice after it has become a habit?

We were able to test this idea in our data by looking at how gym users respond to different interventions that stimulate exercise and temporarily make going to the gym more beneficial. By dividing gym-goers into those who our algorithm determined had formed a habit and those who had not, we explored whether these incentives were more important to one group than another. As we expected, we found that people who had already developed the habit were less sensitive to new rewards for going to the gym.

What does this mean for you? Habits will make you less resilient when there is a good reason to change your behavior. In fact, some variation in routine can create long-lasting habits. So be careful about the behaviors you do repeatedly and make sure you want these things to become habitual. Behaviors we might consider “bad habits,” such as constantly checking your phone, are likely to become automatic and difficult to change.

Track your goals

In January, as you set resolutions and try to put them on autopilot, remember that you can't rely on habits that you can start after a magical number of days. If 21 days have passed and you still have to add a workout to your calendar to make it happen, don't give up hope. Don't worry, the habit of going to the gym is probably still within reach.

Habits are not an illusion. With repetition, most people end up developing routines that are predictable and difficult to deviate from.

Colin Kammerer and Hong Ho contributed to this article.

Cassandra Brabaugh is a health and wellness journalist and editor. Her work can be found in Women's Health, Well+Good, Refinery29, Chicago Booth Review, Harvard Business School Working Knowledge, and others.

Anastasia Boyalskaya is a behavioral scientist and associate professor at HEC Paris. Having started his career in asset management, he advises some of the world's largest investors, integrating behavioral science into their investment processes.

Colin Kammerer is the Robert Kirby Professor of Behavioral Economics at the California Institute of Technology. He was a 2013 MacArthur Fellow and director of the Tianqiao and Chrissy Center for Social Neuroscience and Decision Making.

Angela Duckworth is the Rosa Lee and Egbert Chang Professor at the University of Pennsylvania. She is a 2013 MacArthur Fellow, author of Grit: The Power of Passion and Perseverance, co-founder of Character Lab, co-founder of the Behavior Change for Good initiative, and host of the No Stupid Questions podcast on Freakonomics Radio.

Hong is a doctoral student at the University of Chicago Booth School of Business. His research combines insights from behavioral economics and industrial organization to examine how behavioral biases and economic frictions influence interactions between firms and consumers.

Katie Milkman is the James J. Dinan Professor at the Wharton School of the University of Pennsylvania, author of How to Change: The Science of Getting from Where You Are to Where You Want to Be, co-founder of the Behavior Change for Good initiative, and host of Charles Schwab's “Choiceology” podcast.