What the data actually shows
Large studies of personality change across the lifespan, summarised in work by Roberts and by Soto and colleagues, find that Openness to experience tends to rise into young adulthood and then decline gradually across the rest of life on average. Openness is the trait most associated with curiosity, imagination, and appetite for the new, so a modest decline can show up as somewhat less novelty-seeking and a greater comfort with the familiar.
Habit research, including work associated with Wendy Wood, helps explain the rest. Behaviours that are repeated in stable contexts become increasingly automatic over time, running with less conscious deliberation. Decades of repeated routines naturally produce deeply grooved habits — which can look, from the outside, like rigidity but are really the ordinary mechanics of how habits form.
Against this sits a substantial body of work on neuroplasticity in adulthood: the brain continues to form and reshape connections in response to learning and experience well beyond youth. Older adults routinely acquire new skills, languages, and ideas. So while change may come with more friction, the capacity for it persists across the lifespan.
Why this feels different from how it actually is
The stereotype feels truer than it is partly because deep habits are highly visible while quiet change is not. Someone's decades-old routines are obvious; the new things they have learned or the views they have revised are far less so. We notice the grooves and miss the growth.
There is also a self-fulfilling element. If people expect to become rigid with age — and expect it of others — they may seek out less novelty and try fewer new things, which then produces exactly the inflexibility the stereotype predicted. The belief can help create the outcome it describes.
And a modest average decline in Openness is easy to over-read. 'Slightly less novelty-seeking, on average, across a population' is a much weaker claim than 'people become closed-minded as they age,' but the stronger version is the one that sticks, because it fits a familiar cultural story about getting older.
The honest picture is a gentle drift, not a hardening — and one that is far from inevitable.
What the research says to do about it
The most useful implication is that flexibility appears to be something that can be maintained rather than simply lost. Because the brain stays plastic and learning remains possible throughout adulthood, deliberately continuing to seek out new experiences, skills, and viewpoints works with the evidence rather than against it.
Treating habits as adjustable rather than fixed also helps. Habit research suggests that changing context and surroundings is one of the more effective levers for reshaping automatic behaviour, since stable contexts are what entrench habits in the first place. Deep routines are not permanent; they respond to changed circumstances.
Finally, the research on stereotypes of aging suggests that holding a more accurate, less fatalistic view of your own capacity to change is itself worthwhile, because expectations can shape behaviour. Assuming you can still learn and adapt tends to support actually doing so.
What the research says does not help
Accepting 'I'm just set in my ways now' as a fixed fact tends not to help, and the evidence does not support it as one. Treating a gentle, average decline in Openness as a hard limit can become a self-fulfilling prediction that reduces the very flexibility you assume you have lost.
Relying only on willpower to override a deeply grooved habit is a common but weak strategy. Habit research suggests that established behaviours in stable contexts are run automatically, so trying to out-muscle them through resolve alone, without changing the surrounding context, usually underperforms.
Assuming that the capacity to learn and change simply switches off at some age is also a misreading. Neuroplasticity research indicates the brain keeps adapting throughout adulthood; change may take more effort and repetition, but the door does not close.
Change may come with more friction, but the capacity for it persists across the lifespan.
What this looks like in real life
Grooved habits look like rigidity from the outside
Someone's decades-old routines — the same breakfast, the same route, the same order of doing things — are highly visible, while the new skills they have picked up or the views they have quietly revised are not. We notice the grooves and miss the growth, so ordinary automaticity gets read as a closed mind.
'I'm just set in my ways now'
Treating a modest, average decline in Openness as a hard personal limit tends to become a self-fulfilling prediction: expecting rigidity, you try fewer new things, and the flexibility you assumed you'd lost quietly erodes. The more accurate frame — that the brain stays plastic and change is still possible with more repetition — works with the evidence rather than against it.
Real numbers in context
The personality side of this is best understood as a trend, not a cliff. Lifespan studies (Roberts, Soto and colleagues) describe Openness peaking around young adulthood and then declining gradually on average across later decades — a real but modest shift, with wide individual variation, rather than a uniform hardening that applies to everyone.
The habit and plasticity findings provide the counterweight. Habit research suggests behaviours become automatic with repeated practice in stable settings, which is why long-standing routines feel so fixed; and neuroplasticity research consistently shows the adult brain continues to rewire with learning. Taken together, the numbers describe gentle drift plus deep habits — not the closed-minded inevitability the stereotype implies.