AP Psychology · Lesson 2

Encoding, storing and retrieving memories

Know Know it

Memory has three steps: encoding (getting information in), storage (keeping it) and retrieval (getting it back out). Some encoding is automatic, such as where you sat at lunch. Some takes effort, such as learning new vocabulary.

In the multi-store model, information passes from sensory memory (a brief trace of what we see or hear) to short-term memory, which holds about seven items and fades within seconds unless rehearsed, and then to long-term memory. Working memory is the active workspace of short-term memory. Chunking, mnemonics and the spacing effect (study spread over time) all help. Deep processing, by meaning, produces stronger memories than shallow processing, by sound or appearance.

Long-term memories are explicit (facts in semantic memory and personal events in episodic memory) or implicit (skills in procedural memory, plus conditioned responses). The hippocampus helps form new explicit memories, and the cerebellum helps with implicit ones. Long-term potentiation, the strengthening of synapses with use, is thought to underlie memory.

We retrieve memories by recall, recognition or relearning, helped by retrieval cues. Memory is often best in the same setting (context-dependent memory) or the same internal state (state-dependent memory) as learning. In the serial position effect, we recall the first items (primacy) and last items (recency) of a list best. Quizzing yourself strengthens memory: the testing effect.

Forgetting can come from encoding failure, decay or interference. In proactive interference, old learning disrupts new; in retroactive interference, new learning disrupts old. Memories are rebuilt each time we recall them, so the misinformation effect and source amnesia can change them. Anterograde amnesia blocks new memories, and retrograde amnesia blocks recall of old ones, which often partly return.

Trap Pro goes forward, retro goes back

In proactive interference, the old memory reaches forward and blocks the new one. In retroactive interference, the new memory reaches back and blocks the old one. Ask which memory is hard to recall: if it is the newer one, the interference is proactive.

Worked example Easy

To remember the number 8005551234, Rosa thinks of it as 800, 555 and 1234. Which memory strategy is she using?

  1. Long-term potentiation
  2. ChunkingAnswer
  3. The serial position effect
  4. Iconic memory

How to solve it

  1. Look at what Rosa does to the digits: she groups them.
  2. Grouping items into larger units is chunking.

Why each choice is right or wrong

  • A. Incorrect. Long-term potentiation is a change in synapses, not a strategy a person chooses to use.
  • B. Correct. Rosa groups ten digits into three meaningful units, which is chunking.
  • C. Incorrect. The serial position effect describes which list items we recall best, not a way to group information.
  • D. Incorrect. Iconic memory is a brief visual trace in sensory memory, not a strategy for grouping digits.

Explain Explain it

Task verbs: identify, explain

To explain a memory effect, name it and say which step it works on (encoding, storage or retrieval). Then tie it to the detail in the scenario, such as the setting of the test or the order of learning.

Worked example Medium

Maria studied Spanish in high school and then took Italian in college. Now, when she tries to recall a Spanish word, the Italian word comes to mind instead. What best explains this?

  1. Proactive interference
  2. Retroactive interferenceAnswer
  3. A failure to encode the Spanish words
  4. Anterograde amnesia

How to solve it

  1. Ask which memory is hard to recall: the older one, Spanish.
  2. Ask what blocks it: the newer one, Italian.
  3. New learning blocking old memory is retroactive interference.

Why each choice is right or wrong

  • A. Incorrect. Proactive interference would mean the older Spanish blocks the newer Italian, which is the reverse of what happens.
  • B. Correct. The newer Italian learning disrupts recall of the older Spanish, which is retroactive interference.
  • C. Incorrect. A failure to encode the Spanish words does not fit, because she learned them and the Italian words are what get in the way.
  • D. Incorrect. Anterograde amnesia blocks forming new memories, but Maria formed new memories of Italian just fine.

Explain Your turn

Kai rereads his notes five times the night before a test. Explain why spreading his study over several days and quizzing himself would likely help him remember more a week later.

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Compare with a model answer

A full answer does this

  • Explains that spaced study lasts longer than cramming
  • Explains that quizzing himself strengthens memory more than rereading

Model answer

Because of the spacing effect, study spread over several days is retained longer than the same study crammed into one night. Quizzing himself makes Kai practice retrieval, and the testing effect shows that pulling information out of memory strengthens it more than rereading it, so he would recall more a week later.

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