MOTIVATION IS NOT A CHARACTER TRAIT

What helps motivate you?

I have lost count of the number of people who have sat in front of me and explained, quite matter-of-factly, that the problem is their willpower, and quite firmly, that it is not up for debate. "I have never been able to stick at anything, I start well and then I fall off, I just do not have the discipline." And the best part, "my mum was the same." The problem is they have plenty of evidence, because they have started and stopped so many times that no other explanation seems to fit.

So when I came across a paper from University College London earlier this year, published in PNAS, it resonated with some thoughts I had about motivation. It looked at something almost nobody studies properly, which is how much your motivation moves from one day to the next, and whether that movement changes what you commit to doing.

What the reseachers did

Most research on motivation treats it as a trait. You fill in a questionnaire once, you get a score, and that score defines who you are. This study did something different. Hewitt and colleagues followed 155 people for two weeks and asked them, repeatedly, how motivated they felt in that moment - twenty two times, spread across the fortnight. Alongside that, participants completed short decision making tasks through a smartphone game, choosing whether a reward was worth the effort required to get it.

That gave the researchers 3,344 separate measurements of how motivated people felt, and 845 decisions made in real life rather than in a laboratory. Then they used computational modelling to work out not just whether motivation changed behaviour, but how. It is a small study by headcount and a dense one by measurement, which is an important distinction that I'll come back to.

We think of hourly changes, but could it be daily too?

What they found

The first finding was the simplest. Motivation is not stable. It moved substantially within the same person from one day to the next, which means that if you had measured any of these people once and given them a score, you would have captured a mood rather than a characteristic.

The second finding is more juicy, because it explains the mechanism. Low motivation did not make people lazier. It changed how appealing a reward looked. The same payoff, on a low day, simply felt less worth the effort of getting it. The weighting of that decision had changed. It means the person who does not go to the gym on a Tuesday is not necessarily failing to overcome a temptation. Their brain may have revised its estimate of what the gym is worth today.

The third finding is the one I have definitely experienced myself, and I have to say it has become more obvious as I have got older. Motivation tracked with sleep. When people had slept better, motivation was higher. When they were tired, it was lower. That was true within the same person over time, not just across different people. And there was also a pattern across the week. Motivation ran measurably higher from Thursday through to Sunday than it did from Monday to Wednesday.

When Monday comes along...

And almost everybody starts things on a Monday. The plan gets written on a Sunday, usually after seeing something while scrolling that evening. The new routine, the food plan, the 4.44am wake up. Yes, me. Based on the research, Monday sits in the lower half of the week for motivation, and Tuesday and Wednesday are not much better. By Thursday, when motivation is climbing back up, the plans are worn away. And the conclusion people draw is not that the timing was unhelpful. It is that they are not the sort of person who sticks at things.

There is one more finding worth pointing out, and it is a slightly difficult one. The people who generally find motivation harder were the ones most affected by these daily swings. Their choices varied most. So the very people who have concluded that they lack discipline are the people for whom the conditions matter most, and who would benefit most from working with those conditions rather than against them.

What this does not prove

Honesty time. The strength of this study is the density of measurement rather than the size of the sample, and those are different kinds of confidence. It tells us a lot about these 155 people and rather less about everybody else. Two weeks is also a very short window. We do not know whether the weekly pattern holds across seasons, or in shift workers, or in people whose weekends are not restful - mine are certainly not!

Effort was measured through a well-designed smartphone game and it does capture something real about how people weigh reward against effort. Whether it maps onto getting to a 6am class in February is a question this study cannot answer.

And the sleep finding, which is the one I find most useful clinically, is a correlation observed within a person over time. Sleep and motivation rose and fell together, and again, whether one drives the other, or something else drives both, this study cannot tell us. One thing I will say, the authors put their data and their analysis code online for anyone to check. That is not as common as it should be, and I think that is admirable.

Why this matters

The story people tell themselves about their own discipline is almost always harsher than the evidence supports, and that story does real damage. When somebody has decided that the problem is their character, they stop looking for other explanations. They do not consider that they might be under-slept or under-fuelled. And it will almost certainly never occur to them that the day they chose to begin was working against them.

They just conclude that they are the sort of person who fails at this, and that conclusion becomes load bearing.

This paper does not dismantle that on its own, but it does establish something quite specific and quite useful. The thing people think is fixed about them moves day to day, and is therefore addressable.

What to actually do with this information

Two things I feel will be helpful to think about before embarking on a new routine or habit. Start when you have something in reserve rather than when you flip your weekly calendar over to a new week. Thursday is not a failure of commitment, it is (on this evidence), a better bet than Monday. And take your sleep seriously. Of everything, sleep is the area you have the most influence over, and it is the one that showed up most consistently alongside motivation.

One last thing...

For most of the people I work with, this was never a motivation problem. It is about understanding your own rhythms, the things that shape your choices and understanding where your effort is actually worth spending time on. Most people are not short of willpower, they're short of information about themselves, and are trying to follow plans that were built for somebody else.

That is the part of my work that matters most, and it is what makes my work different. No generic protocols and no rules handed down from somewhere. We lean in to find where the bottlenecks actually are, learn what your body is doing and why it is doing it, and then build something that works with how you work rather than against it.

So you can level up towards the version of yourself you already suspect is in there.

Reference:

Hewitt, S.R.C. et al. (2025). Day-to-day fluctuations in motivation drive effort-based decision-making. Proceedings of the National Academy of Sciences, 122(12). DOI: 10.1073/pnas.2417964122