I was listening to an episode of Live Well Be Well with Sarah Ann Macklin — her interview with Cambridge neuroscientist Hannah Critchlow — and a section of it stopped me. Not because it told me something I hadn’t suspected, but because it gave a very precise account of something I’d watched people go through without quite being able to explain. Including, at various points, myself.
It was the part about breakups. And the part about why leaving someone does not, it turns out, mean you stop.
There is a particular experience that almost everyone who has ended a relationship knows, and that almost no one talks about without embarrassment. You were the one who left. You made the decision. You had your reasons, and they were real, and at some level you still think they were right. And yet here you are, three months later, checking their Instagram at eleven at night for no reason you could honestly defend. Looking to see if they seem fine. Looking to see if they seem not fine. Just — looking.
The standard story we tell about this is a moral one. We pathologize it. We call it weakness or mixed feelings or proof that we didn’t really want to go. What Critchlow describes is something more structurally interesting than any of that, and considerably less flattering to the narrative of the tidy, decided exit.
The brain doesn’t process “over” — it processes open
Critchlow draws on a concept developed by the psychologist Daniel Wegner called transactive memory. The idea is that in any long-term relationship, cognition is not entirely individual. The two people share a cognitive system — a distributed memory and processing network across both of them. One person remembers the social calendar. The other holds the emotional map of the friendship group. One navigates the practical logistics. The other carries the family history. This division is not always conscious or negotiated. It just happens, over time, as an emergent feature of two people structuring their lives together.
When the relationship ends, what you lose is not just the person. You lose the other half of a cognitive system you had been operating for months or years. Whole categories of information — things you would have processed together, checked with each other, delegated to the other — suddenly have nowhere to go. The brain, which had been running at full capacity partly because it was offloading to an external node, now has to reclaim all of that processing itself. While also trying to reconfigure everything else.
Critchlow’s phrase for it: losing an external hard drive.
This is why the exhaustion after a breakup — even a mutual one, even a right one — can feel wildly disproportionate to what people around you think it should. It is not dramatic. It is not you failing to hold it together. It is a brain rebuilding an entire operating system while still being asked to run everything on it.
Why you keep looking
But there is something more specific underneath the looking. And this is the part Critchlow describes that I keep thinking about.
The brain is a prediction machine. Its core function — more fundamental than memory, more fundamental than emotion — is building accurate models of what is likely to happen, and updating those models against incoming information. Uncertainty is not just unpleasant. It is, in neurological terms, a system failure: the brain cannot do its primary job when the model has gaps it cannot fill.
A relationship — even an ended one — leaves gaps. You shared a life with this person. You knew their patterns, their moods, their reactions. The model was rich and detailed and constantly updated by proximity. When contact stops, the model goes stale. And a stale model is an open question. The brain, doing what it is built to do, keeps returning to the open question. Keeps looking for the information that would let it update, close the loop, and move on.
You are not checking their social media because you miss them. You are checking because your brain is still trying to answer a question it was never formally told to stop asking. The silence that follows a breakup is not neutral. The brain reads it as uncertainty. And research on uncertainty and the stress response is consistent on one point: uncertainty is the one condition the brain cannot comfortably leave alone.
The shame we add on top
What makes this particularly hard is the layer of judgment that gets loaded onto the behaviour.
If you still look, clearly you weren’t ready to leave. If you still think about them, clearly you’re not as over it as you said. The looking becomes evidence — in your own internal court, and sometimes in the accounts you give other people — of something unresolved, something weak, something that should be further along by now.
But the looking is not evidence of ambivalence. It is evidence of a prediction system doing what prediction systems do. The brain is not looking because it is confused about the decision. It is looking because it is trying to resolve the information gap that the decision created. Those are different things, and collapsing them together — treating the neurological behaviour as emotional evidence — is where a lot of unnecessary suffering gets manufactured.
The clarity of a decision and the closure of a neural loop are two separate processes on two separate timelines. The first can be complete while the second is still running. Knowing this does not make the second process faster, but it changes what the behaviour means. The looking is not a relapse. It is a brain doing its job in a situation where the job has no clean ending.
What eventually closes the loop
Critchlow doesn’t offer a shortcut to this, and I think that honesty is worth thinking about.
The brain closes open loops when it gets information — not when you decide to move on. New experiences, new relationships, new patterns eventually supply enough new data that the old model becomes less salient. Not replaced, exactly, but outweighed. The loop doesn’t close because you will it closed. It closes because the brain eventually builds a more current model that the old one no longer fits inside.
This means the most honest thing you can do in the period of the looking is to understand what it is. Not a failure of resolve. Not evidence against your own decision. Just a very well-documented feature of how the brain handles the loss of a shared cognitive system. Something to be seen clearly rather than moralized about.
The breakup was your decision. The looking is your neurology. Both can be true without one undermining the other.
Sovereign Mind lens
This is exactly the kind of problem the Sovereign Mind framework was built to address: the way the brain’s automatic processes generate behaviours we then judge morally, rather than understanding structurally.
- Unlearning: The assumption that “over it” and “not looking” should arrive at the same time. We’ve absorbed a cultural script that maps emotional resolution onto behavioural closure — that someone who has genuinely moved on simply doesn’t look back. What Critchlow’s work makes clear is that the neural process of closing an information gap operates on its own timeline, independent of the emotional decision.
- Restoration: The brain trying to close a transactive memory gap is a brain under cognitive load — not dramatically, but persistently. The conditions that help are not distraction or forced busyness. They are the same ones that help the brain process anything difficult: rest, movement, time away from the input that keeps the old model active. Not as avoidance, but as genuine space for the system to reorient. The brain needs new data to build a new model, and that data can only arrive if you are actually present in your life and not managing an ongoing loop.
- Defense: The social pressure to be over it by a certain point — and the accompanying shame when you are not — is a form of cognitive interference. Other people’s discomfort with how long grief and transition take is real, but it is not information about your process. Recognising the pressure to perform resolution faster than it is actually happening, and declining to let that pressure define the story you tell yourself about your own behaviour, is a form of protection. The looking has a biological explanation. You are not obligated to explain it as weakness.
I keep thinking about the phrase Critchlow uses. The brain reads the silence as uncertainty. Not as peace. Not as closure.
As a question it has not yet been given enough information to answer.
That reframe does not make the looking stop. But it changes what you do with it — which is, I think, exactly the kind of distinction that matters when you are inside something you haven’t fully found your way through yet.
