An interesting piece that appeared earlier this month in the
British Psychological Society’s
Research Blog. 
How to form a habit
This has nothing to do with nuns’ clothing. Habits are those
behaviours that have become automatic, triggered by a cue in the
environment rather than by conscious will. Health psychologists are
interested for obvious reasons – they want to assist people in
breaking unhealthy habits, while helping them adopt healthy ones.
Remarkably, although there are plenty of habit-formation theories,
before now, no-one had actually studied habits systematically as
they are formed.
Phillippa Lally and her team recruited
96 undergrads (mean age 27) and asked them to adopt a new
health-related behaviour, to be repeated once a day for the next 84
days. The new behaviour had to be linked to a daily cue. Examples
chosen by the participants included going for a 15 minute run
before dinner; eating a piece of fruit with lunch; and doing 50
sit-ups after morning coffee. The participants also logged onto a
website each day, to report whether they’d performed the behaviour
on the previous day, and to fill out a self-report measure of the
behaviour’s automaticity. Example items included ‘I do it
automatically’, ‘I do it without thinking’ and ‘I’d find it hard
not to do’.
Of the 82 participants who saw the study through to the end, the
most common pattern of habit formation was for early repetitions of
the chosen behaviour to produce the largest increases in its
automaticity. Over time, further increases in automaticity dwindled
until a plateau was reached beyond which extra repetitions made no
difference to the automaticity achieved.
The average time to reach maximum automaticity was 66 days,
although this varied greatly between participants from 18 days to a
predicted 254 days (assuming the still rising rate of change in
automaticity at the study end were to be continued beyond the
study’s 84 days). This is much longer than most previous estimates
of the time taken to acquire a new habit – for example a 1988
book claimed a behaviour
is habitual once it’s been performed at least twice a month, at
least ten times. In fact, even after 84 days, about half of the
current study participants had failed to achieve a high enough
automaticity score for their new behaviour to be considered a
habit.
Unsurprisingly
perhaps, more complex behaviours were found to take longer to
become habits. Participants who’d chosen an exercise behaviour took
about one and a half times as long to reach their automaticity
plateau compared with the participants who adopted new eating or
drinking behaviours.
What about the effect of having a day off from the behaviour?
Writing in 1890, William James said that a behaviour must be
repeated without omission for it to become a habit. The new results
found that a single missed day had little impact on later
automaticity gains, either early in the study or later on,
suggesting James may have overestimated the effect of a missed
repetition. However, there was some evidence that too many missed
repeats of the behaviour, even if spread out over time, had a
cumulative effect, reducing the maximum automaticity level that was
ultimately reached.
It seems the message of
this research for those seeking to establish a new habit is to
repeat the behaviour every day if you can, but don’t worry
excessively if you miss a day or two. Also be prepared for the long
haul – remember the average time to reach peak automaticity was 66
days.
This research has a serious shortcoming, acknowledged by the
researchers, which is that it depended entirely on participants’
ability to report the automaticity of their own behaviour. Also,
the amount of data made it hard to form clear conclusions about the
need for consistency in building a habit. However, the study
provides an exciting new approach for exploring habit formation and
future research could easily remedy these shortcomings.
_________________________________
Lally, P., van Jaarsveld,
C., Potts, H., and Wardle, J. (2010). How are habits formed:
Modelling habit formation in the real world. European Journal
of Social Psychology DOI: 10.1002/ejsp.674