Memory and Forgetting
This domain tests the structure of memory stores, the types of memory, and the specific mechanisms that explain why material is lost.
The multi-store model
Atkinson and Shiffrin proposed three stores. Sensory memory holds raw impressions briefly - iconic (visual) about half a second, echoic (auditory) two to three seconds. Short-term memory holds about 7 ± 2 chunks for roughly 20–30 seconds without rehearsal. Long-term memory is comparatively unlimited and durable. Information passes between stores through attention and rehearsal.
Kinds of memory
Declarative memory is explicit and divides into episodic (personal events) and semantic (facts); non-declarative memory is implicit and includes procedural skills. Retrieval can be recall or recognition.
Improving memory
Chunking, maintenance and elaborative rehearsal, organisation, mnemonics, spaced rather than massed practice, and deep semantic processing instead of rote repetition.
Why we forget
- Encoding failure: the material never entered memory properly.
- Trace decay: the memory fades with time.
- Interference: proactive when old learning disrupts new, retroactive when new learning disrupts old.
- Retrieval failure: the memory exists but the cue is missing.
- Motivated forgetting: repression in the Freudian account. Ebbinghaus's forgetting curve shows steep early loss followed by a plateau; the serial position effect shows primacy (long-term) and recency (short-term) advantages.
Worked example
A pupil practises French in the morning and Spanish in the evening, then cannot recall the morning French. The newer Spanish material is disrupting the older French, so this is retroactive interference. If the morning French had disrupted the evening Spanish, the interference would be proactive.
Traps
Confusing proactive with retroactive interference; claiming short-term memory is unlimited with rehearsal; presenting repression as a firmly established experimental finding.