2.6 Retrieving Memories

Recall means retrieving information without cues, as on a fill-in-the-blank or essay question ('Name the four lobes of the cortex'). Recognition means identifying information when you see it, as on a multiple-choice question ('Which of these is a lobe of the cortex?'). Recognition is usually easier because the answer itself acts as a retrieval cue.

A retrieval cue is anything that helps you access a stored memory: a smell, a word, a place or a feeling. Memories are stored in webs of associations, and a cue activates part of the web, which helps bring up the rest. This is one reason priming (2.2) works.

The common thread is that the conditions at encoding become retrieval cues. Matching them gives you more cues. Since you usually can't study in the exact room where you'll take a test, a good workaround is to study in several different places, so your memory doesn't depend on one setting.

• Context-dependent memory: you recall information better in the same physical environment where you learned it. In one classic study, divers who learned words underwater recalled more underwater, and those who learned on land recalled more on land.
• State-dependent memory: you recall better when you're in the same internal physical state as when you learned, such as being caffeinated or tired. Information learned while drinking alcohol is recalled better when drinking again, though it's also learned poorly in the first place.
• Mood-congruent memory: your current mood makes it easier to recall memories that match it. When you're sad, sad memories come to mind more easily, which can keep a low mood going.

The testing effect is the finding that practicing retrieval, by quizzing yourself, makes memories stronger than spending the same time rereading. Each time you pull a memory out, you strengthen the pathway to it. Flashcards, practice questions and closing your notes and writing what you remember are all retrieval practice.

Metacognition means thinking about your own thinking: judging what you know, what you don't and which strategies work for you. Students often feel they know material after rereading it because it looks familiar, but recognizing something isn't the same as being able to recall it. Self-testing gives you accurate feedback, so you can spend time on what you actually don't know.

The best study plans combine retrieval and encoding research: space your sessions out (2.4), quiz yourself instead of rereading, process material for meaning, and check your understanding honestly. These strategies take more effort and feel harder in the moment, but that effort is what builds stronger memories.