Beyond habit stacking
What it really takes to sustain change
In January, there is no shortage of advice on how to change behaviour, whether getting fitter, eating more healthily, taking up a sport, or simply becoming a slightly improved version of oneself through better routines.
The advice tends to be similar: start small. Break behaviours down. ‘Stack’ new habits onto existing ones. Make the desired action easy, obvious, and repeatable. For example, advice suggests that everyday life is quietly re-engineered: coffee becomes a cue for going for a walk with coffee in hand, kitchens double as gyms so you can lift weights while you prepare food, and reminders on your screen nudge you to move between responding to emails.
Of course, this all sounds sensible, and indeed, there is plenty of evidence that we can acquire habits that have tremendous sticking power. A now-classic study by psychologist Wendy Wood illustrates this: cinema-goers were given either fresh or stale popcorn while watching a film. Those watching the film ate roughly the same amount regardless of quality. By contrast, participants given the same popcorn in a standard meeting room, where eating popcorn is not customary, ate far less of the stale batch. The explanation here is that the behaviour was not being guided by taste or conscious preference, but by context and routine.
This understanding of habits is not only widely accepted in popular culture but has also underpinned many public health campaigns that aim to steer everyday behaviours toward healthier, more sustainable lives.
So, have we found a sure-fire solution for making change happen? If we reduce challenges to bite-sized chunks, does this give us a general method for addressing everything from fitness and diet to burnout, wellbeing, and work–life balance?
Behaviour change as a matter of design?
The challenge here is that this approach carries a set of assumptions that are often not discussed: that habits are mechanical and that, if we repeat a behaviour often enough, it will run on autopilot. Indeed, there is a notion that to get a habit to stick, all we need to do is to repeat it for 21 days, a ‘behavioural urban myth’ that despite being consistently debunked continues to circulate!
And there is a wider issue at play: the current narrative about habit assumes these behaviours are things that happen to people, rather than tools people actively use to manage their lives. The challenge comes from our own experience of doing these allegedly automatic behaviours: actually getting out and going to the gym does not seem any easier on a wet and dark weekday night despite being weeks into our suopposed new habit, the lure of an unhealthy snack remains hard to resist and we might just throw things in the bin rather than rinse and put them in the appropriate recycling container.
This is the challenge that psychologists Blair Saunders and Kimberly More set out to explore with the hypothesis that the complexity of different behaviours is at the heart of why some ‘habits’ stick and others do not. They suggest that some behaviours are simple, so taking a pill is easy and can readily fit among daily tasks, such as pairing with mealtimes. This is in contrast to other behaviours that may look simple from a distance but closer up, they are far more complex. So going to the gym, preparing healthy meals, or using active travel are complex mainly because they are not single actions but sequences of activities that have to be fitted around the rest of life.
They all involve planning, time, coordination, but also social judgment (e.g. others may ask why we would pay to go to the gym when it is possible to run outside for free). They are also easily disrupted: we can feel tired, there are always competing demands, or day-to-day obstacles can easily knock us off course. This means that simple repetition does not make these behaviours effortless in the way habit theory often implies should be the case.
Hence, Saunders and More make the case that what looks like a stable habit from the outside is, in fact, often a process of ongoing adjustment to overcome the range of things that can get in the way.
To test this idea, they asked about 200 people to identify four behaviours they were currently engaging in as either healthy or environmentally friendly. Some of these were quite simple behaviours, such as packing a reusable coffee cup or wearing a face covering (the study was run during the COVID pandemic). Other behaviours, by contrast, were more complex, such as making a healthy lunch, sorting their recycling, and exercising.
They asked the participants to report how habitual their chosen behaviours were using the Self-Reported Automaticity Index, a short questionnaire that asks you if a given behaviour is, for example, something ‘I do without thinking’. Then, over the following two weeks, they asked the same people to keep track of any purposeful strategies they used to engage in these behaviours: this might be calling on a friend for support, reminding themselves of the positive outcomes, or adding something extra to make the behaviour more fun.
They found that for simple behaviours, people were less likely to report using strategies to motivate them, which makes sense: as they point out, you don’t need much self-encouragement to pack a reusable cup once that behaviour is habitual.
But for complex behaviours, those who reported the strongest habits used purposeful strategies just as often as those who reported only very weak habits for the very same behaviours. So those who said their exercise routines were strongly habitual reported were using just as wide an array of tactics and tricks to get themselves going.
It merits pausing here for a moment to unpick the implications of this: essentially, it suggests that, for many behaviours, if you want to create successful habits, then there is no let-up in the work you need to encourage and support yourself if you want to maintain the behaviour.
This puts to rest the idea that many of the behaviours we might want to make part of our lives can become completely ‘automatic’, especially if they require multiple steps, time, and/or exertion. As they point out, ‘automaticity’ may work on days we don’t have competing demands, feel tired or are distracted by work and caring responsibilities.
But of course, this is not how life works, and much of the time, the habits we aim for will need support from intentional processes. This might include setting up so that the things you need for the behaviour are readily available, adding music or podcasts to the activity to make it more fun, reminding yourself of how the behaviour is aligned with your values, or focusing your attention on the first steps of the behaviour to give yourself momentum.
The philosophy of habit
This explains why philosopher Elizabeth Grosz argues that routines are less about switching off effort than about learning to cope with the world as it is. People who keep going to the gym, cook regularly, or commute actively are not free from effort. However, they do become better at dealing with it. They learn when motivation tends to dip, what makes things harder, and which small adjustments help them carry on.
In this sense, routines work like skills: a skilled cyclist still encounters hills, traffic, and bad weather, but knows how to respond. Similarly, someone with a well-established exercise routine hasn’t eliminated resistance; they’ve just learned how to work around it.
This also explains why people with strong ‘habits’ still rely on reminders, planning, self-talk, or small rewards. As Grosz puts it, habits involve a kind of quiet, practical intelligence, something learned through doing, rather than thinking it through from scratch each time.
Seen this way, the problem with many habit-based approaches is not that they are mistaken, but that they mistake the nature of the challenge. They treat effort as something to be designed away, when, for many important behaviours, the work is learning how to persist.
Once habits are understood as ways of managing complexity, rather than escaping it, their limits and their value become much clearer.
Unpacking complex behaviours?
Another consideration is whether complex behaviours can be shifted by isolating the part of the behaviour that carries the greatest leverage, ideally using data and experimentation to guide where to intervene. This is the approach proposed by James Elfer and colleagues, who argue that cultural change (in our language, complex behaviours) becomes possible when it targets specific behaviours at critical moments.
In their work with AstraZeneca, rather than attempting to improve the overall complex behaviour of hiring experience end-to-end, they focused narrowly on one aspect of the hiring manager's behaviour in the first few minutes of interviews. Using large-scale experiments with over 1,200 candidates, they tested different ways of shaping that moment, from boosting confidence to signalling inclusivity. The most effective intervention turned out to be simple: normalising nerves as an expected part of the process, a small shift that made candidates feel more at ease and better able to perform.
The wider lesson is that change did not come from removing complexity, but from intervening at the point where uncertainty and emotional load were highest.
Conclusions
Perhaps it is worth asking why behavioural science and the technologies, policies, and designs it informs can all too often remain so invested in the promise of effortlessness.
Perhaps part of the appeal is surely practical, as systems that appear to work automatically are easier to scale, justify, and fund. Effortlessness reassures us that change can happen without asking for anything more, but as we have set out, this rarely holds for the behaviours that matter most. This logic is especially visible in cultures of wellbeing and productivity. People are encouraged to optimise sleep, exercise, diet, focus, and mental health, often simultaneously, while being told that the right routines will make it all feel natural. When that ease fails to materialise, the gap is all too often internalised as a personal failure.
The problem, then, is not that habit-based approaches are wrong but that they carry a moral story about how change should feel: smooth, frictionless, and self-sustaining, leaving little room for the reality that many worthwhile changes will always be effortful because they involve managing complexity and trade-offs.
We can perhaps then reframe habits as ‘routines of competence’ rather than ‘mechanisms of automation’, as this allows us to recognise persistence and adaptation as a feature, not a bug.
The question then becomes not how to make change feel easy, but how to support people in staying with what is hard, without treating effort as something that needs to disappear.