Memory forms through four connected steps: encoding, consolidation, storage, and retrieval. Each stage has a unique role, and disruption in any part can weaken or erase the memory.
Book: Remember: The Science of Memory and the Art of Forgetting
Think about the last time you learned something new. That knowledge exists because your brain completed four key steps to form memory: encoding, consolidation, storage, and retrieval.
(1) Encoding
Encoding is the first step where your brain takes in information from your senses (sight, sound, smell, emotion, meaning). What you pay attention to gets translated into a neurological "code" so your brain can work with it. Without encoding, nothing new gets recorded in memory.
Attention is crucial here. You remember what you want to remember, and things you ignore are unlikely to be encoded.
(2) Consolidation
Once encoded, your brain organizes and links the scattered neural activity into a single pattern of associated connections, like weaving threads into a tapestry. Consolidation strengthens memory and reduces the likelihood of fading. Sleep and repetition both play important roles here.
The consolidation process can be fragile. If a boxer gets knocked out or a drinker blacked out, they often forget what happened during the event because their brain's capacity to consolidate recent events was disrupted.
(3) Storage
The consolidated memory becomes long-lasting through structural and chemical changes in neurons. This information isn't stored in a single location, but distributed across the brain regions that were active during the experience.
For example, visual details are stored in visual areas, sounds in auditory areas, and emotions in emotional circuits, all of which are interconnected. This is also related to the dual-coding theory we learned before.
(4) Retrieval
Retrieval is the process of calling a memory back into awareness. When you recall a memory, you reactivate the web of connections that formed it.
But memory retrieval isn't like pulling a video file from storage. Memory retrieval is reconstructive: the brain rebuilds the experience, often blending accurate recall with interpretation. That's why words can distort memory. Our memories are oftentimes not reliable because the retrieval process is error-prone.
These four steps must work together. A failure in one means the memory may never form or may be lost. The hippocampus is particularly crucial for forming new memories. Without it, people can remember their past but struggle to create new long-term memories, as shown by the famous case of patient H.M.