2.1 Memory

Memory as an information-processing system

Psychologists model memory in three stages: encoding (getting information in), storage (retaining it over time), and retrieval (getting it back out). The Atkinson-Shiffrin model proposes information flows through sensory memory, short-term memory, and long-term memory. Problems at any stage can cause forgetting.

Short-term vs. long-term memory

Sensory memory holds brief impressions of stimuli. Short-term (working) memory holds about 7±2 items for under a minute unless rehearsed; chunking and maintenance rehearsal extend capacity and duration. Long-term memory has essentially unlimited capacity and is strengthened through elaborative rehearsal, which connects new info to existing knowledge.

Types of long-term memory & forgetting

Long-term memory splits into explicit (declarative) memory — episodic (events) and semantic (facts) — and implicit (nondeclarative) memory, like procedural skills and classical conditioning. Forgetting results from encoding failure, storage decay, retrieval failure, interference (proactive/retroactive), or motivated forgetting. The serial position effect shows better recall for first (primacy) and last (recency) items.

Key terms

Encoding

The process of getting information into memory storage.

Working (short-term) memory

Temporary storage holding about 7±2 items for a brief period unless rehearsed.

Explicit vs. implicit memory

Explicit (declarative) memory involves conscious recall of facts/events; implicit (nondeclarative) memory involves skills and conditioned responses without conscious effort.

Serial position effect

Tendency to better recall items at the beginning (primacy) and end (recency) of a list.

Interference (proactive vs. retroactive)

Proactive: old memories interfere with new learning. Retroactive: new memories interfere with recall of older information.

Try an AP-style question

What process keeps it in working memory?

1. Chunking
2. Elaborative rehearsal
3. Retrieval cue
4. Maintenance rehearsal