How long does it take to form a habit?

It takes an average 66 days to form a new habit, according to new research by Phillippa Lally and colleagues from the

ucl.ac.uk/hbrc" target="_self">Cancer Research UK Health Behaviour Research Centre based at UCL Epidemiology and Public Health.

The team has completed a groundbreaking investigation into how people form habits, published last month in the European Journal of Social Psychology. Here Phillippa explains the key factors in creating and breaking habits and how we can help set up for ourselves new patterns of behaviour.

What exactly takes 66 days?

In our study, we looked at how long it took people to reach a limit of self-reported automaticity for performing an initially new behaviour (that is, performing an action automatically), and the average time (among those for whom our model was a good fit) was 66 days.

How do you define a habit?

Habits are behaviours which are performed automatically because they have been performed frequently in the past. This repetition creates a mental association between the situation (cue) and action (behaviour) which means that when the cue is encountered the behaviour is performed automatically. Automaticity has a number of components, one of which is lack of thought.

How do you measure the strength of a habit?

We use a self-report measure of automaticity (items from Verplanken and Orbell's Self Report Habit Index (2003)). An example item is 'I do this without having to consciously remember'. Participants rate how much they agree with this statement for their chosen behaviour.

What are the key factors in breaking or gaining habits?

To create a habit you need to repeat the behaviour in the same situation. It is important that something about the setting where you perform the behaviour is consistent so that it can cue the behaviour. If you choose a context cue, for example after lunch, we don't think that it matters if you eat lunch at different times in the day.

Breaking habits is very difficult. The easiest way is to control your environment so that you do not encounter the cue which triggers your habit. It is difficult to break any habit even when you are motivated to do so. If you are ambivalent about breaking it then you will be less likely to succeed.

New habits do not stop the old habits from existing; they just have to become stronger influences on behaviour.

What happens if we miss an opportunity to perform an action that will help us build a habit?

In our study we showed that missing one opportunity did not significantly impact the habit formation process, but people who were very inconsistent in performing the behaviour did not succeed in making habits. We do not yet know what level of consistency is necessary to form a habit.

Do men and women acquire or break habits differently? Or young and old?

We don't have any evidence to suggest that men and women or young and old people acquire habits differently.

What are the implications of your findings for people trying to form healthy habits or break unhealthy ones?

It can take much longer than many people think to form a habit and it is important to persevere. If someone wants to form a habit they should specify clearly what they will do and in what situation and try to do this consistently. Over time it will start to happen more easily and require less effort.

Why did you decide to investigate this area?

We are interested in helping people to change their health behaviours, and if we can help them to form habits for these behaviours it will be easier for them to maintain them long term.

What are the next steps for your research?

We hope to conduct a similar study and measure a number of factors which might help to explain the variation we found among participants in the time it took them to reach their limit of automaticity. We are also conducting a trial of a simple weight-loss intervention based on the principles of habit formation.