A study published in The Journals of Gerontology: Series B followed 625 Swedes for fifty-seven years and found something that has nothing to do with how good anyone’s memory actually was. School anxiety at age 13 — not age 10, not grades, not IQ, not family income — predicted how badly people would rate their own memory at age 67. The actual test scores didn’t care about any of this. Only the felt sense of remembering did. John Locke worked out why that split is possible 336 years before anyone ran a structural equation model to prove it: he argued that the self isn’t the body, and isn’t even the mind in some objective sense. It’s whatever you can remember being. Get the memory wrong, on his account, and you haven’t misjudged yourself. You’ve become someone slightly different.

The Quick Verdict

Question	What we found
Who ran the study?	Gideon Neidenmark, Catherine Tuvblad, and Jonas Persson, using data from Örebro University’s IDA program
Where and when?	The Journals of Gerontology: Series B, covered by PsyPost on September 9, 2026
How big was it?	625 participants, assessed around age 10 in 1965, age 13 in 1968, and age 67 in 2022
What predicted late-life memory complaints?	School anxiety at 13 — and only at 13, not at 10 — even after controlling for current anxiety and depression
What didn’t predict it?	Childhood cognitive ability, school grades, social well-being, and family socioeconomic status — none of it moved the needle
What did Locke already argue?	In An Essay Concerning Human Understanding (1690), Book II, Chapter 27, personal identity is constituted by continuity of consciousness and memory — not by an unchanging soul or an unchanging body

The Quick Version

A 2026 study tracking 625 Swedes for fifty-seven years found that anxiety at school, specifically at age 13, predicted how poorly they’d rate their own memory at 67 — independent of their actual test scores, current mental health, grades, or income. John Locke argued in 1690 that personal identity just is the thread of memory and consciousness running through a life, not a fact about the body or the brain’s objective condition. If he’s right, a distorted memory of yourself isn’t a symptom sitting on top of the self. It’s a change to the self.

What the 2026 Study Actually Found

Gideon Neidenmark didn’t set out to study anxiety. He’s a doctoral student working inside the IDA program — Individual Development and Adaptation — a Swedish research effort that has followed Örebro schoolchildren since 1965, back when David Magnusson started it as a project on how kids adapt over a lifetime, not a study anyone expected to still be running six decades later. Neidenmark’s own framing, in comments to PsyPost, was almost apologetic about the scale of what he had access to: “I am fortunate enough to be involved in a longitudinal study called the IDA-project with data spanning six decades.” What he wanted to know was narrower and stranger than the dataset itself. Why do people’s own sense of their memory so often fail to track how their memory actually performs?

The design let him ask that question with real teeth. Researchers had measured cognitive ability, school grades, social well-being, family socioeconomic status, and anxiety symptoms in the same children twice — once around age 10, once around age 13 — decades before anyone knew what to do with the data. Then, in 2022, they came back to 625 of those now-67-year-olds and asked them to rate their own memory abilities, alongside checking their current anxiety and depression.

Only one thing from childhood came back significant: anxiety at age 13. Not age 10 — the same measure, taken three years earlier in the same children, showed nothing. Something specific to early adolescence, not childhood anxiety in general, was doing the work. And the effect survived the obvious objection. Even after the researchers statistically removed the influence of how anxious or depressed someone was right now, at 67, the thread back to age 13 held. This wasn’t a case of anxious teenagers becoming anxious old adults who happen to also feel bad about their memory. It was a specific, decades-dormant signal.

Just as striking is the list of things that predicted nothing. Cognitive ability at 10 or 13 — no relationship to memory complaints at 67. School grades — nothing. Social well-being — nothing. Family income — nothing. Neidenmark put it plainly to PsyPost: “I think what surprised me the most was that social well-being, socioeconomic status, cognitive ability and school performance during childhood and adolescence were not related to subjective memory in later life.” The variables you’d bet on, the ones that sound like they should matter, mostly didn’t. The one that felt like a footnote turned out to carry the whole finding.

His summary of the stakes is worth sitting with directly: “I think the most important take-home message is that our childhood and adolescence are related to our abilities in later life, particularly that our psychological health in our youth is related to how we perceive and rate our own memory abilities. This also persists even when we account for current psychological health.” Notice what’s doing the work in that sentence. Not “our memory.” Our perception of our memory. Those are different objects, and the study is precise about which one it’s tracking.

Locke Already Argued This, 336 Years Before Anyone Ran the Numbers

John Locke’s An Essay Concerning Human Understanding (1690) contains, in Book II, Chapter 27, one of the strangest and most durable arguments in the history of philosophy: that personal identity has nothing essential to do with having the same body, or even the same soul, over time. What makes you the same person you were yesterday, Locke argues, is that you can remember being that person. As he puts it, identity reaches “as far as this consciousness can be extended backwards to any past Action or Thought” — no further. Lose the memory, on his account, and you haven’t just lost information about yourself. You’ve lost the thing that made that past self your self.

Locke calls “person” a forensic term — a word built for assigning credit, blame, reward, and punishment, not a word describing a substance sitting inside you. That’s a deliberate move. He’s not offering a metaphysical curiosity. He’s explaining why it would be unjust to punish someone for an act they have no conscious memory of ever having done, even if it’s the same body, even if a soul theorist could prove it’s the same immaterial substance underneath. Locke’s most famous illustration — a prince’s consciousness transferred into a cobbler’s body, memories and all — is designed to make you feel the pull of his answer before you’ve agreed to the argument. Ask who wakes up in that cobbler’s body and you already know: the prince. The body didn’t decide. The memory did.

This is where the 2026 study stops being merely a curiosity about self-report bias and starts looking like Locke’s argument running on real data. The IDA-project measured two entirely different things in the same 67-year-olds: what their memory actually does, and what they believe about what their memory does. Locke gives you the vocabulary to say why those can come apart so completely, and why the second one isn’t a lesser, distorted echo of the first. On his account, the felt sense of your own memory is a component of who you are, in a way that a neuropsychological test score simply isn’t. A number on a memory test describes an organ. A person’s sense of their own remembering describes the person.

What Did Locke Actually Mean by Personal Identity?

1. Identity follows consciousness, not substance. Locke argues explicitly that sameness of person doesn’t require sameness of body or soul — a claim that was genuinely radical against a philosophical tradition that had assumed the soul did all the work.
2. Memory is the mechanism, not just evidence. You’re not the same person as your 13-year-old self because a continuous soul connects you. You’re the same person because your consciousness now can reach back and lay hold of that earlier consciousness.
3. “Person” is a forensic term, built for judgment. Locke defines persons as agents capable of law, happiness, and misery — which is why memory matters so much to him: you can only justly be praised or blamed for what you’re conscious of having done.
4. The self can outrun the body and the brain. Locke’s prince-and-cobbler example exists to force the intuition that identity travels with memory even when nothing about the physical substrate agrees — a thought experiment that reads uncannily like a philosophical preview of dissociative and confabulation research three centuries later.

This Site Has Covered the Self Before — Here’s the Difference

The post on Hume’s bundle theory argued that there’s no continuous self at all underneath experience — just a bundle of passing perceptions the mind stitches into a story after the fact. Locke and Hume actually disagree here, and the disagreement matters for this study. Hume would say the “self” that rates its own memory at 67 was never a stable thing to begin with, so of course it drifts from the test scores. Locke would say something more specific: there is a real, trackable identity, and it’s constituted by the very memory-consciousness that went sideways in adolescence. The study’s finding fits Locke’s framework more precisely than Hume’s, because it shows a particular, dateable disruption — age 13, not a vague absence of selfhood — producing a particular, measurable downstream effect fifty-four years later.

The post on childhood adversity and mindfulness covered a different Swedish-adjacent finding: a Brown University study where mindfulness helped adults with hard childhoods more than adults without one. Different mechanism, same shape. Both studies locate a lever in early life that current-day interventions or current-day mental health can’t fully erase or fully explain away.

The post on Kierkegaard, Heidegger, and the Stoics on anxiety treats anxiety as a signal worth interpreting rather than a malfunction to suppress. This study gives that idea an unusually long tail: an anxiety signal at 13 that nobody was tracking for its long-term significance turns out to have been laying down something that would resurface as a memory complaint at 67. It’s the strongest empirical argument I’ve seen on this site for taking adolescent anxiety seriously as more than a phase.

The post on Montaigne argued self-knowledge is a practice of ongoing self-noticing, never a finished project. Locke would agree with the mechanism, if not the mood — for him, the self isn’t unfinished by choice. It’s unfinished because it’s made of memory, and memory keeps getting revised, dropped, and reconstructed for as long as you’re alive to do the remembering.

Where This Doesn’t Hold Up

None of this makes Locke a psychometrician, and the honest version of this piece says so directly.

The IDA-project data is correlational and self-reported at the endpoint. Neidenmark himself is careful about this: “Like with any articles, we should be cautious about considering these findings as fact or infer causality.” A 54-year gap between the anxiety measurement and the memory-complaint measurement makes any causal story hard to nail down cleanly — plenty happened to these 625 people in between that the study can’t account for. The sample is also a single Swedish city cohort born in the mid-1950s, not a general or contemporary population; whether the same pattern would show up in today’s 13-year-olds, raised on a completely different set of school pressures, is an open question the researchers don’t claim to answer. Neidenmark’s own next step, he told PsyPost, is checking whether these childhood factors relate to actual memory performance and brain structure later in life — which is exactly the piece this study doesn’t yet cover.

Locke’s argument has its own limits, and they’re not small ones. Philosophers have spent three centuries pointing out the obvious gap in a pure memory theory of identity: what about the years you can’t remember at all — early childhood, a blackout, a long illness? If identity requires the thread of consciousness reaching back to an act, does the person who can no longer remember that act stop being identical to the one who did it? Locke’s theory, taken literally, produces some genuinely strange verdicts about transitivity that later philosophers (Thomas Reid, most famously, with his “brave officer” objection) took apart in detail. This post isn’t claiming Locke solved personal identity in 1690. It’s claiming that his specific insight — that the felt continuity of memory is not a report on the self but a component of it — gives this 2026 finding a name and a reason, rather than just a statistic.

A Practice Worth Trying

Neither Neidenmark’s team nor Locke wrote this as a five-step plan, but the shared shape of what they found points somewhere specific.

1. Separate the test score from the story. If you find yourself convinced your memory is failing, ask what evidence that’s actually based on — a missed appointment, or a feeling that’s been with you since long before this week. The study suggests these can be entirely different things wearing the same complaint.
2. Take adolescent anxiety seriously as more than a passing stage. If you’re raising or teaching a 13-year-old who’s anxious about school specifically, this data doesn’t say panic. It says the psychological weather at that particular age might matter more, later, than test scores or grades ever will.
3. Notice which “you” is doing the remembering. Locke’s point is that your sense of your own past isn’t a neutral readout — it’s actively constructed by whoever you are now. A bad week can make your memory of last year look worse than it was. That’s not you lying to yourself. On Locke’s account, it’s just what a self made of memory does.
4. If memory complaints are new and specific, get them checked anyway. None of this is a reason to wave off a genuine, sudden change in memory function. Philosophy explains why the feeling of decline can outrun the reality — it isn’t a substitute for a real cognitive assessment when something’s actually changed.

The Remembering Was the Point

Neidenmark’s team wasn’t testing Locke. They were asking a narrower, more measurable question — do early-life psychological factors predict how people rate their own memory decades later — and they found something sharper than “anxious kids become anxious old adults”: one specific age, one specific variable, moving one specific outcome, while grades, IQ, and income sat on the sidelines doing nothing at all. Locke wasn’t running longitudinal surveys. He was working out, from first principles and a handful of thought experiments about princes and cobblers, why a person’s sense of who they are travels with memory and nothing else — three centuries before anyone had a structural equation model to check his work. Neither needed the other to be right. It’s just hard to ignore that a 1690 chapter about consciousness and a 2026 study with a fifty-seven-year follow-up period are pointing at the same unglamorous mechanism: the self isn’t what a test says about you. It’s what you can still reach, remembering.

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This post discusses a 2026 longitudinal psychology study alongside a classical philosophical text. It isn’t a diagnosis of anyone’s memory or anxiety. If memory changes are new, sudden, or worsening, or if anxiety is significantly affecting your life, a doctor or therapist can help in ways a philosophy essay can’t.