A Little Background

Before we dive headlong into depths of change theory, it’s worth discussing one of the most widely accepted theories of behavior change.

Back in the early 1980’s, James O. Prochaska and his colleagues at the University of Rhode Island developed a model to outline the process of behavior change [1]. It’s called the "Transtheoretical Model of Behavior Change" (or TTM) because it’s based on 300 different theories of psychotherapy and an analysis of the leading theories of behavior change [2] It details the six stages of change:

James O. Prochaska's "Transtheoretical Model of Behavior Change" (or TTM) details six stages of behavior change.

James O. Prochaska's "Transtheoretical Model of Behavior Change" (or TTM) details six stages of behavior change.


Unaware of or not ready to make a particular change


Evaluating whether to make a change or not


Ready and taking steps to make a change a part of your life


In the throes of making the change itself


Working to sustain the change and prevent relapse


No more effort necessary, the change is a part of your life


Where the TTM pushed the envelope was in thinking about change as a process that happens over time, rather than an "all or nothing" moment in people’s lives [2,3]. It also lines up well with our own common sense - we’ve all experienced the waxing and waning of our motivation and interest levels in taking on something new.

But the TTM isn’t without its shortcomings [4]. The very notion of "stages" give the impression that behavior change is a straightforward progression of discrete steps. The reality, of course, is much more complicated. Every change we take on can jump forward and backward through the process, sometimes skipping steps along the way. Behaviors that made it to maintenance can easily drop back to contemplation at the drop of a hat.



The 21 Day Fallacy

This idea - that change isn’t a straightforward process - is a little different from an idea that pervades our self help culture... If you asked the average person on the street, "How long does it take to build a new habit?," most would reply "21 days" without batting an eye.

This 'set it and forget it' idea essentially argues that you can move yourself all the way from contemplation to termination in three weeks, with the new behavior now a permanent fixture in your life.

It appears that this myth actually originated from anecdotal evidence of patients who received plastic surgery and seemed to adapt to their new appearance in 21 days [5]. The truth, of course, is much more nuanced.

A study carried out at the University College London asked 96 participants to make a new eating, drinking, or exercise behavior part of their routine. The study was looking to see how long it took for these new behaviors to become automatic [6].

On average, it took 66 days until a habit became automatic, with plenty of variation (a range of 18 to 254 days) between the (relatively simple) eating, drinking, and exercise behaviors. Generally speaking, the more complex the behavior, the longer it took for it to become automatic.

Each change, it turns out, takes much longer than a magical 21 days of consistent effort to turn into a habit. Keep this in mind as you set out on the next one.