Nature of Memory

Memory is best understood as retaining and recalling information over time, and how long that information needs to be held depends entirely on the task at hand — sometimes we only need to hold on to something for a few seconds (an unfamiliar phone number until we dial it), and sometimes we retain it for a lifetime (basic arithmetic learned in early schooling). Rather than picturing memory as one giant storehouse that keeps everything we have ever learned, psychologists conceptualise it as a process made up of three separate but connected stages: encoding, storage, and retrieval. Every piece of information we ever remember has to pass through all three.

Encoding is the first stage — the process by which incoming information is first registered and converted into a form the memory system can actually use. When a stimulus reaches our sense organs, it produces neural impulses that different areas of the brain process further; encoding is what takes that raw sensory input, extracts some meaning from it, and represents it in a usable way.

Storage is the second stage. Once information has been encoded, it must be retained and held over a period of time so that it is available later — storage is simply this holding process.

Retrieval is the third and final stage. Stored information is only useful if a person can bring it back into conscious awareness when it is needed — for solving a problem, making a decision, or answering a question. Because these are three distinct stages, memory failure can occur at any one of them: we might fail to recall something because we never encoded it properly to begin with, because it was stored weakly, or because storage was fine but we simply cannot access or retrieve it when we need to. …