“Object Permanence” and ADHD: Why “Out of Sight, Out of Mind” Isn't Quite Right

By Mark Ryan, BACP Accredited Psychotherapist and NCPS Accredited Relationship Therapist

You haven't heard from your partner in a few hours, and it's started to feel like more than a busy afternoon. Or you're the one being asked why you didn't text back, unsure how the day slipped past without the thought crossing your mind again. This tendency to forget actions or check ins with partners can sometimes feel like being forgotten. In ADHD communities online, this gets called object permanence, or rather, a lack of it. The term has spread widely because it captures something real. It's also, in the literal sense, the wrong term entirely, and getting that right matters for how you address what's underneath it.

The confusion here isn't a small, pedantic detail. If a partner comes away believing the other has a fundamental cognitive gap in understanding that people continue to exist unseen, that's a frightening, almost clinical-sounding thing to sit with, and it points toward the wrong kind of concern entirely. The real mechanism is both more specific and, in a practical sense, more workable than that.

What object permanence means

Object permanence is a real, well-established concept in developmental psychology, first described by Jean Piaget. It refers to a milestone infants reach, usually within their first year, understanding that an object still exists even when it can't currently be seen. A baby without this understanding treats a toy hidden under a blanket as though it has vanished entirely. Adults with ADHD have this understanding just as securely as anyone else. Nobody believes a partner has ceased to exist because they've left the room.

This isn't a controversial or subtle point among clinicians and researchers who study either ADHD or child development. It's simply that the ADHD community's use of the phrase has drifted a long way from Piaget's original meaning, borrowing a memorable, evocative label from developmental psychology to describe a completely different, adult experience. That borrowing is understandable, the phrase captures something real about the felt experience, but it isn't the accurate name for what's being described.

What's happening has a different, more precise name, and understanding the difference matters, since treating this as a fundamental gap in someone's grasp of reality is a much bleaker, and less accurate, picture than what the research supports.

The real mechanism: prospective memory

The relevant term is prospective memory, the ability to remember to carry out an intended action, or think of someone, at a future point without an external reminder prompting it. A foundational study comparing adults with ADHD to matched peers found a large-scale impairment specifically in the planning stage of prospective memory, forming and holding onto an intention to act later, while the stages of recalling and executing an already-formed plan showed only small differences between groups (Fuermaier, Tucha, Koerts, Aschenbrenner, Westermann, Weisbrod, Lange and Tucha, 2013). In plain terms, the breakdown tends to happen early, in forming a durable intention in the first place, rather than in caring enough to follow through once the intention is clearly held.

This has a specific, practical implication that's easy to miss. If the weak link is specifically at the planning stage rather than at recall or execution, then the most effective point to intervene isn't reminding someone harder once the moment has passed. It's making the original intention itself more durable at the point it's formed, before the conversation ends, before the phone goes back in a pocket. That single distinction is what makes the intervention described later in this piece work as well as it does, rather than being another well-meant reminder that doesn't address where the actual difficulty lives.

It also explains why a partner with ADHD can sometimes seem to follow through reliably on some things and not others, with no obvious pattern to the difference. A plan formed vividly, in a moment with full attention and few competing demands, has a real chance of surviving. A plan formed in passing, half-attending while doing something else, doesn't get the same durable encoding in the first place, regardless of how much either partner cared about the outcome. The unevenness itself is informative rather than random.

This distinction matters more than it might first appear. A weak intention isn't the same as a weak commitment. Someone can care intensely about reaching out to a partner and still fail to form the kind of durable, self-sustaining intention that survives an intervening few hours of distraction, meetings, and other demands on attention. The caring and the follow-through are, mechanically, two separate things, and ADHD affects the second far more reliably than the first.

This is a meaningfully different picture from object permanence. Nobody is forgetting that the other person exists. What's harder is holding onto the specific intention to reach out, to reply, to check in, once the moment that prompted the thought has passed and nothing in the immediate environment is there to prompt it again.

Why this shows up so clearly in relationships

This isn't just a lab finding with no real-world echo. A separate study found that everyday prospective memory performance directly predicted procrastination behaviour in adults with ADHD, and that weaker prospective memory helped explain why ADHD symptoms and procrastination travel together so consistently (Altgassen, Scheres and Edel, 2019). Replying to a message, following up on a plan, checking in on how someone's day went, are all, in cognitive terms, delayed intentions competing for space with everything else that's currently in front of you. The people who felt most invested in remembering still forgot the most, not because the intention was weak, but because the underlying system for holding onto delayed intentions is what ADHD affects.

A concrete version of this might look like a partner reading a message on a train, feeling a genuine rush of warmth and the clear intention to reply properly once they're off, then arriving home, being met at the door by a dog, a delivery, a phone call, and the message simply never resurfacing that evening. Nothing about getting off the train weakened the original feeling. The specific plan to act on it, formed in a five-second window with no anchor to bring it back to mind later, was the part that didn't survive contact with an ordinary evening.

For the partner on the receiving end, this rarely feels like a cognitive footnote. Being forgotten, even briefly and even for entirely explicable reasons, touches something more fundamental than logistics, a live question about whether you matter enough to be held in mind. That reaction is reasonable on its own terms, and it can coexist with the reality that the forgetting wasn't a verdict on how much you're loved.

What makes this specific pattern harder to sit with than an isolated missed message is its repetition without an obvious trigger. A single forgotten reply after an unusually chaotic day is easy enough to set aside. The same thing happening on an unremarkable Tuesday, with nothing unusual competing for attention, is what starts to feel personal, since there's no visible explanation standing in the way of the alternative reading, that it simply wasn't important enough to hold onto. Knowing that ordinary, low-demand moments are, if anything, easier for an already-strained prospective memory system to lose track of, precisely because nothing about them stands out enough to anchor the intention, can make that pattern less confusing without making it less real.

Nobody believes a partner has ceased to exist because they've left the room.

What can help

The most encouraging part of this research is that prospective memory isn't fixed or untrainable. A recent study tested a specific technique called episodic future thinking, vividly imagining the moment of carrying out an intention before moving on, and found it meaningfully improved everyday follow-through in adults with ADHD compared with standard reminders alone (Altgassen, Heinrich and Edel, 2026). Concretely, this might look like picturing the specific moment of sending a text, where you'll be, what the phone will look like in your hand, rather than simply deciding in the abstract to text later. The vividness of the imagined moment appears to give the intention something firmer to attach to.

This works, per the theory behind it, because it moves the intention from an abstract decision into something closer to a stored memory of an event that hasn't happened yet, complete with a specific setting the mind can later be triggered by. It's a small habit to build, taking five extra seconds to picture the moment rather than simply resolving to remember, though the research is honest that its benefit was reduced once verbal ability was accounted for, meaning it likely works better for some people than others, and isn't a guaranteed fix for everyone equally.

External structure tends to help more than willpower here too, since willpower depends on the same system already carrying the load. A recurring time to check in, a shared reminder both partners can see, or a habit tied to something else already routine, brushing teeth, leaving for work, gives the intention an anchor that doesn't depend on it surfacing unprompted from memory alone.

Anchoring a new intention to an existing habit works for a specific reason, and knowing that reason makes the advice easier to trust rather than just follow blindly. An established routine already has its own reliable cue, the toothbrush in hand, the front door closing, that doesn't rely on prospective memory at all to trigger it. Attaching a new intention to that existing cue borrows its reliability, rather than asking a fragile, unsupported intention to survive entirely on its own. This is also why a reminder that arrives at a random, disconnected moment tends to work less well than one tied to something that was always going to happen anyway.

Where being forgotten has already accumulated into something heavier than any single instance, that specific kind of loneliness deserves its own honest conversation, separate from whatever practical system gets built going forward. A better reminder system doesn't automatically resolve the hurt of every time it wasn't there before.

How this fits with the rest of the picture

This piece sits alongside the broader picture covered in how ADHD gets mistaken for not caring in a relationship, and the specific, related pattern covered in why ordinary feedback can land as a much bigger threat than it was meant to be. Together they point toward the same underlying reframe, that a great deal of what looks like not caring, not listening, or not valuing feedback properly is better explained by specific, researched differences in how attention, memory, and emotional reactivity work, rather than by a deficit in how much someone loves their partner. None of the individual mechanisms is the whole story on its own, and a couple who recognises more than one of these patterns at play isn't dealing with something more severe, just something with more than one moving part, each best addressed on its own terms rather than folded into a single, vaguer complaint about forgetfulness or distance.

How therapy can help

Couples navigating this often arrive already knowing the facts, ADHD affects memory, forgetting isn't personal, and still finding the hurt just as sharp each time it happens. Facts rarely resolve feelings on their own, and the useful work usually sits in that gap, building genuine trust in the explanation over time, rather than simply accepting it as true in the abstract.

That gap tends to close through repeated, lived evidence rather than through the explanation being repeated more forcefully. A partner starts to trust that the forgetting isn't personal not because the mechanism has been explained clearly enough, but because they've watched a real system get built, tested, adjusted, and hold over months, alongside honest acknowledgement each time it didn't. Explanation without visible change tends to feel like being asked to accept a theory. Explanation alongside a genuine, ongoing effort to build around the difficulty tends to land as something closer to being taken seriously.

Where a workable system hasn't held despite real attempts, the work often shifts to understanding what specifically is getting in its way, whether the intention isn't being formed vividly enough, whether the reminder itself isn't reaching the right moment, or whether something else, exhaustion, overload, a different underlying pattern, is quietly undermining an otherwise sound plan.

It also helps to check, honestly, whether what looks like a prospective memory failure is something closer to the withdrawal pattern described elsewhere in this series, a felt reluctance to reach out rather than a genuine lapse in remembering to. The two can look identical from outside, a message left unanswered, but they call for different responses. One is helped by a better external system. The other needs the underlying reluctance itself named and understood before any reminder system will make much difference.

If you feel like now might be the right time to talk this through with a therapist, I offer a free 30-minute consultation in person (in London) or online. Either partner is welcome to reach out first, whether you're the one navigating this pattern day to day or the one on the receiving end of it, still working out how much of what you're seeing is mechanism and how much is something else entirely.

About the Author

Mark Ryan is a BACP Accredited Psychotherapist and NCPS Accredited Relationship Therapist working in person across central London, from rooms in Pimlico, Kensington, and Angel. He works with couples, individuals, and polycules on relationship issues including jealousy, affairs and betrayals, sex problems, and considered separation. His practice is integrative, sex-positive, and affirming of all relationship structures and identities.

References

Fuermaier, A. B. M., Tucha, L., Koerts, J., Aschenbrenner, S., Westermann, C., Weisbrod, M., Lange, K. W., & Tucha, O. (2013). Complex prospective memory in adults with attention deficit hyperactivity disorder. PLOS ONE, 8(3), e58338. https://doi.org/10.1371/journal.pone.0058338

Altgassen, M., Scheres, A., & Edel, M. A. (2019). Prospective memory (partially) mediates the link between ADHD symptoms and procrastination. ADHD Attention Deficit and Hyperactivity Disorders, 11(1), 59–71. https://doi.org/10.1007/s12402-018-0273-x

Altgassen, M., Heinrich, H., & Edel, M.-A. (2026). Episodic future thinking improves everyday prospective memory performance in adults with a previous diagnosis of attention deficit hyperactivity disorder by community providers. Journal of Attention Disorders, 30(5), 705–721. https://doi.org/10.1177/10870547261416467