Why Does My Child Know Something One Day and Forget It the Next?

Yesterday, your child spelt a word correctly three times. Today, it looks completely unfamiliar. At home they can tell you their times tables, but in class they cannot bring an answer to mind. During a lesson they seem to understand a new idea, yet later they cannot explain it or use it without help.

This inconsistency can be puzzling and frustrating for everyone. It can look as though the learning was never secure, or as though the child was not listening or trying. Often, that is not what is happening. A child can understand information at the time and still find it difficult to hold, store or retrieve when the situation changes.

Learning is more than understanding in the moment

Several processes sit between first meeting an idea and being able to use it fluently. A child needs to pay attention to the information, make sense of it, hold it in mind, connect it with what they already know and gradually establish it in longer-term memory. Later, they need to find and retrieve it in response to the right cue.

Retrieval also needs to become increasingly automatic. A spelling may be recalled during a focused practice activity but disappear when the child is also inventing a sentence, remembering punctuation and trying to write neatly. A number fact may be available at the kitchen table but harder to reach in a busy classroom or timed task. The knowledge may be present without yet being reliably accessible under pressure.

What is working memory?

Working memory is the small mental workspace we use to hold and work with information for a short time. A child uses it when following a multi-step instruction, keeping the beginning of a sentence in mind while reading the end, doing part of a calculation mentally or deciding how to phrase an answer.

That workspace has a limited capacity. Imagine a child listening to a question while remembering the instructions, decoding words, choosing vocabulary, spelling and preparing an answer. Each demand occupies some of the available space. If too many demands arrive together, information can be lost before it is used. This is sometimes described as cognitive load.

This does not mean the child has no memory or did not understand. It means access becomes less reliable when the task asks them to listen, remember, process and respond at the same time. You can read more in What is working memory and why does it matter for dyslexia?.

This does not mean the child has no memory or did not understand.

Memory, dyslexia, attention and other learning needs

Poor or inconsistent recall does not automatically mean dyslexia. However, some dyslexic learners experience difficulties with aspects of verbal memory, phonological processing, automaticity and retrieving learned written information. A word may need many more encounters before its spelling becomes secure, and effortful reading or spelling can leave fewer mental resources for remembering the wider task.

Working-memory difficulties can also occur independently of dyslexia or alongside ADHD, autism, developmental language differences and other learning needs. Different children may show a similar difficulty for different reasons, which is why one sign should never be treated as a diagnosis.

With ADHD, attention may vary while information is first being encoded. If only part of an instruction or explanation was registered, the later gap can look like forgetting. At other times, a child has genuinely understood the idea but finds it difficult to hold and manipulate several pieces of information. Both experiences are possible, and neither should be reduced to carelessness. Dyslexia and ADHD can overlap, but they are distinct profiles.

Why can they remember everything about Minecraft, football or dinosaurs?

Parents sometimes wonder how a child who forgets a spelling can remember every Minecraft recipe, football statistic or dinosaur name. Memory is strongly influenced by interest, meaning, repetition, existing knowledge, context and emotional engagement. Favourite topics are revisited voluntarily, connected to a rich network of prior knowledge and often discussed or used many times in different ways.

A new spelling or classroom instruction may have fewer connections and may need to be retrieved in a distracting environment or under time pressure. That contrast is not evidence that a child chooses when to remember. It shows that memory works best when information is meaningful, well connected and practised enough to become readily available.

Practical ways to help at home and at school

Helpful support reduces avoidable memory demands while giving important learning repeated opportunities to become secure. Depending on the child and task, this may include:

• •giving short, manageable instructions and checking understanding before adding the next step;
• •using visual prompts, worked examples, checklists, word banks, number lines or a visible timetable;
• •reducing unnecessary copying and keeping key information available rather than expecting it all to be held mentally;
• •using spaced retrieval: returning to learning after gradually increasing gaps rather than concentrating all practice into one session;
• •building in overlearning, with calm and varied practice beyond the first correct response;
• •linking new learning to something the child already understands;
• •using retrieval practice — asking the child to bring an idea to mind — rather than relying only on repeated rereading;
• •allowing additional processing time before repeating or rephrasing a question;
• •encouraging external memory aids without presenting them as cheating or dependence;
• •and keeping practice low-pressure enough that anxiety does not add another demand.

The aim is not to remove memory from learning. It is to avoid using limited working-memory capacity on tasks that do not need to test it, while strengthening recall of the knowledge that matters. The article Why can my child read one day and struggle the next? explores a related kind of inconsistency.

Helpful support reduces avoidable memory demands while giving important learning repeated opportunities to become secure.

When might it be worth looking more closely?

Occasional forgetting is part of learning. It may be worth exploring further when difficulties are persistent, occur across settings and sit alongside concerns about reading, spelling, written work, attention, language, organisation or broader learning — particularly when they continue despite appropriate teaching and support.

Start by sharing specific examples with the teacher or SENCo and asking what they notice in school. Useful questions include whether the child manages better with visual support, shorter instructions or more time, and whether literacy skills are developing as expected. A formal assessment is not always the next step, but where dyslexia is one possibility, a child dyslexia assessment can explore the wider pattern of strengths and difficulties rather than looking at memory in isolation.