The myth of a fixed self and what happens when we stop believing it.
There’s a phrase I hear so often in my consulting room it’s started to lose its edges—almost a cliché people say and then stop noticing:
“That’s just how I am.”
Sometimes it arrives with resignation. Sometimes with a kind of defiance. But always with the same quiet assumption underneath: that who we are is settled. That the self is a finished object — something we received at some point, perhaps by thirty, perhaps earlier, and now must simply live with. William James, the pioneering psychologist, put it starkly: by thirty, character is “set in plaster and will never soften again.”
If that were true, therapy would be little more than damage control.
It isn’t true.
Let that settle for a moment.
In one remarkable study (Harris et al., 2016), teacher ratings at fourteen had surprisingly little power to predict how those same people were rated at seventy-seven—by themselves, and by someone who knew them well. Over sixty-three years, the overall stability was low.
Not entirely, though. When the authors accounted for rater effects, one thread still held: stability of moods showed significant continuity, and conscientiousness was close behind.
Life reshuffles us—messily, unevenly.
Some patterns loosen. Some persist.
But the larger truth remains: who we were is not a life sentence.
We are not the same people we were.
We never stay still long enough.
The psychologist Christian Jarrett tells a resonating story. At a British boarding school a boy throws a piece of butter across a dining table, towards a king on a painting. He is punished. Labelled a rebel. Written off.
A few years later, the same boy is chosen as house captain — the school’s most trusted leadership role. He doesn’t just survive the responsibility. He thrives.
What happened? The science would say: a role was entrusted to him that required something he hadn’t yet shown, and the role itself drew it out. Social investment theory calls this process trait change through social commitment — when we step into a meaningful role, the demands of that role begin to reshape who we are. Not through willpower. Not through self-help mantras. Through the noiseless, persistent pressure of being needed in a particular way.
I see this constantly in my work with clients navigating transitions. A new responsibility, a new relationship, a new context — and something shifts. Not because they decided to be different, but because life asked them to be, and they rose to meet it.
But here is where personality science, for all its rigour, begins to feel incomplete to me. It can tell us that traits change. It can even tell us how. What it struggles to capture is what that change means to the person living through it — the confusion of it, the loss, the strange relief.
Marriage reshapes us. So does bereavement. So does unemployment. Research shows these events don’t just happen to us; they alter our traits measurably. Marriage tends to increase self-control and forgiveness. Prolonged unemployment can erode conscientiousness — the loss of structure making it harder to rebuild structure, a painful cycle that tightens the longer it runs.
What the data doesn’t say, but what I encounter in the therapy room, is that personality change through life events is not always growth. It can be contraction. Confusion. A version of yourself you don’t recognise and aren’t sure you want. And this is precisely where the therapeutic work begins — not to resist the change, but to turn toward it. To ask: what is this reshaping asking of me?
Among the findings that stay with me, two feel particularly alive.
The first: the body doesn’t draw a clean line between anxiety and excitement.
Racing heart.
Sweaty palms.
That bright, electric alertness.
Same physiology. Different story.
And simply relabelling “I’m nervous” as “I’m excited” measurably improves performance and reduces distress. You ride the wave rather than drowning in it. From an existential standpoint, this is not a technique. It is a recognition. In the existential tradition, anxiety has never been merely a symptom to eliminate.
It’s a signal.
Something meaningful is at stake.
And if we learn to meet that signal as energy rather than threat, we’re simply catching up to what the tradition has long intuited: anxiety can mobilise us—if we’re willing to stay with it, rather than flee.
The second: the most conscientious people don’t use more willpower than the rest of us. They use less. They design their environment so the difficult choice rarely needs to be made. They don’t keep the temptation in the cupboard. This sounds like behavioural psychology, and it is. But underneath it sits a profoundly existential insight: we are responsible not only for our actions, but for the world we build around ourselves. The conditions we create for our own becoming. To arrange your life so that it draws out the person you want to be is not a trick. It is a form of care.
Whenever I discuss any of this with clients, one concern inevitably surfaces: wouldn’t changing be fake?
This is the question I find most interesting, and the one that sits closest to the existential work.
We tend to equate authenticity with whatever feels natural right now — our defaults, our automatic reactions, the habits we’ve never thought to question. But the research suggests something that I think Sartre would have recognised immediately: people report feeling most authentic not when indulging their existing patterns, but when acting in alignment with their ideal self.
If you deeply value human connection but happen to be socially anxious, reaching out isn’t a betrayal of who you are.
It’s fidelity to who you’re trying to become.
Sartre reminds us there’s no fixed essence waiting to be “honoured.” We are always in the process of becoming.
Heidegger speaks of authenticity as the willingness to own our possibilities, rather than drift along with whatever is expected.
When I hold those ideas alongside what the research keeps showing, I land in the same place:
Authenticity isn’t something we start with.
It’s something we choose—
and choose again.
Many people arrive in my consulting room carrying a quiet conviction that they’re fundamentally stuck—too anxious, too passive, too broken to change.
The science doesn’t promise effortless transformation.
But it does something more important: it dismantles the myth of the fixed self.
It tells us—over decades, across lives—that who you are is not a verdict.
It is a work in progress.
And here is the finding that moves me most: simply knowing that personality is malleable — holding what researchers call a growth mindset about your own traits — is itself enough to reduce anxiety and depression. The belief in your capacity to change is not wishful thinking. It is an empirically supported psychological resource.
From an existential perspective, this isn’t news. It’s confirmation.
The tradition has always insisted we are not objects with fixed properties. We are beings in motion—always becoming.
Our past informs us, yes. But it does not imprison us.
And each moment—quietly, stubbornly—still carries the possibility of a different response.
A different choice.
A different way of being in the world.
We are not set in plaster. We never were.
The question is not whether change is possible. The question — and it is the question I hold space for every day in my work — is this:
Knowing you have the capacity to shape who you are, who will you choose to become?
