Multi-store model of memory

Stores in the MSM

• sensory register

• stm

• ltm

sensory register

• initial stage where info from senses enters the system

• capacity: very large

• duration: very short (decays quick)

• encoding: modality-specific (depends on senses, diff SR for diff senses)

Sperling research on SR

• Ps shown grid of letters, asked to recall whole grid, on average recall 4.32 letters

• SR holds nearly all info briefly

• info decays quickly

• attended info moved to STM, unattended fades quickly

STM

• temporary workspace for info that is consciously processed

• duration: 15-30 seconds

• capacity: 7+-2 items

• encoding: mainly acoustic

• forgetting: info decays (info fade overtime) or displaced (new info push out old)

STM maintenance rehearsal vs elaborative rehearsal

• maintenance = repeat info, keeps active in STM, helps transfer to LTM

• elaborative = rehearsal by linking meaning or association, help transfer to LTM

Peterson and Peterson research on STM duration

• Ps recall trigrams after varying intervals 3,6,9,12,15,18 sec

• Ps had to count backwards in 3s from random number to prevent rehearsal

• good recall at short intervals, performance dropped sharply after 15-18 sec

• STM limited duration, info decays rapidly without rehearsal

Baddeley exp on encoding

• four list of words to recall in correct order

• acoustically similar/dissimilar + semantically similar/dissimilar

• STM: worse recall with acoustically similar words → shows STM encodes acoustically

• LTM: worse recall with semantically similar words → shows LTM encodes semantically

LTM

• permanent memory system

• duration: up to a lifetime

• capacity: virtually unlimited

• encoding: primarily semantic

eval of MSM (weakness)

• MSM too simplistic - does not explain dual task exp (poor performance when tasks are similar, but good when tasks are diff), cannot be explained by MSM bc it treats STM as one store (WMM challenge bc STM is multiple components there)

• MSM too much emphasis on rehearsal for STM transfer to LTM

• MSM too simplistic - states LTM is one store, C.W cannot recall episodic LTM, but can still recall procedural LTM (MSM les valid bc LTM is multiple stores)

eval of MSM (strength)

• brain damage patient H.M - STM work, LTM not work shows LTM and STM diff stores (WMM valid)