Research: There is no magic number for how long it takes to develop habits
Apr 22, 2023
Washington [US], April 22 : Getting dressed and making your way to the gym can be a chore at first. You may gradually create the habit of getting to the gym and swiftly transitioning to your Zumba class or treadmill run. According to a new study by social scientists at Caltech, it takes an average of six months to acquire a gym habit.
The same study looked at how long it takes healthcare professionals to develop the habit of washing their hands: an average of a few weeks.
"There is no magic number for habit formation," said Anastasia Buyalskaya, a marketing assistant professor at HEC Paris. Caltech's Colin Camerer, Robert Kirby Professor of Behavioural Economics and director and leadership chair of the T&C Chen Centre for Social and Decision Neuroscience, and researchers from the University of Chicago and the University of Pennsylvania are among the other authors of the study, which appears in the journal Proceedings of the National Academy of Sciences. Xiaomin Li, a former Caltech graduate student and postdoctoral scholar, is also an author.
"You may have heard that it takes about 21 days to form a habit, but that estimate was not based on any science," Camerer says. "Our works support the idea that the speed of habit formation differs according to the behaviour in question and a variety of other factors."
The study is the first to use machine learning tools to study habit formation. The researchers employed machine learning to analyze large data sets of tens of thousands of people who were either swiping their badges to enter their gym or washing their hands during hospital shifts. For the gym research, the researchers partnered with 24 Hour Fitness, and for the hand-washing research, they partnered with a company that used radio frequency identification (RFID) technology to monitor hand-washing in hospitals. The data set tracked more than 30,000 gymgoers over four years and more than 3,000 hospital workers over nearly 100
"With machine learning, we can observe hundreds of context variables that may be predictive of behavioural execution," explains Buyalskaya. "You don't necessarily have to start with a hypothesis about a specific variable, as machine learning does the work for us to find the relevant ones."
Machine learning also let the researchers study people over time in their natural environments; most previous studies were limited to participants filling out survey shifts.
The study found that certain variables had no effect on gym habit formation, such as time of day. Other factors, such as one's past behaviour, did come into play. For instance, for 76 per cent of gymgoers, the amount of time that had passed since a previous gym visit was an important predictor of whether the person would go again. In other words, the longer it had been since a gymgoer last went to the gym, the less likely they were to make a habit of it. Sixty-nine per cent of the gymgoers were more likely to go to the gym on the same days of the week, with Monday and Tuesday being the most well-attended.
For the hand-washing part of the study, the researchers looked at data from healthcare workers who were given new requirements to wear RFID badges that recorded their hand-washing activity. "It is possible that some health workers already had the habit prior to us observing them, however, we treat the introduction of the RFID technology as a 'shock' and assume that they may need to rebuild their habit from the moment they use the technology," Buyalskaya says.
"Overall, we are seeing that machine learning is a powerful tool to study human habits outside the lab," Buyalskayasays.