Psychology Unit 1- Memory MULTI STORE MODEL

The Atkinson and Shiffrin Model

• 1968
• Stimulus input --> Sensory Memory--> attention--> Short term Store--> rehearsal--> Long term store---> rehearsal loop (back to STS)
• Sensory memory- Visual, auditory, tactile coding, limited capacity, very brief duration- Iconic store (visual), Echoic store (auditory), Haptic store (tactile) EVIDENCE: Sperling (1960)- chart of three rows of letters very short exposures, recall immediately (4/5 out of 12). Then with tones (per row- 3 out of 4) Lab- high control, replicable, artificial stimulus. Consent, debriefing.
• Short term store- mainly acoustic coding, limited capacity, brief duration- DISPLACEMENT- pushed out before going to LTM to make room for incoming items
• Long term store- mainly semantic coding, unlimited capacity, unlimited duration- INTERFERENCE- info confused with similar info

Glanzer and Cunitz (1966)

• Free recall: can recall items in any order
• Condition 1- recall immediately after presentation
• Condition 2- distractor task- backwards in 3's- 30 secs- before recall
• Distractor task- disrupted recency effect- DISPLACEMENT of last few words- recency (fragile STM) but early words recalled (primacy effect- strong LTM)
• Lab- Controlled, replicable, artifical, repeated & averages, consent, debrief

STM

Digit span technique: Measures capacity of STM, repeat digits in order of presentation, no. of digits increase until recall inaccurate

Serial recall: recall in order of presentation

Factors affect capacity of STM

Influence of LTM, Reading aloud, pronunciation time, individual differences.

Peterson & Peterson (1959)

• How long in STM without rehearsal
• TRIGRAMS- consonants 
• Backwards in 3's from specific no e.g. 451. Intervals of 3, 6, 9, 12, 15, 18 secs
• 80% trigrams recalled after 3 sec interval- recall worse longer intervals e.g. 18 secs- less than 10% correct- INFO DISAPPEARS QUICKLY FROM STM WHEN REHEARSAL IS PREVENTED
• Lab- artificial, loss of info (capacity limits not duration?- counting displaced trigram?), trigrams on earlier trails confusion (PROACTIVE INTERFERENCE), consent, debrief

Factors affecting duration of STM

• Rehearsal, intention to recall, amount of info to recall

Factors affection duration of LTM

• Experimental designs, depth of learning, pattern of learning, nature of material to learn

Encoding STM Conrad (1964)

•  6 consonants- rapid sequence on screen
• Condition 1- acoustically similar (BGCTDV)
• Condition 2- acoustically dissimilar (FJXMSR)
• Write down in serial order- harder if acoustically similar- caused confusion- we must convert visual to acoustic in STM
• Lab- controlled, artificial, students- not representative, consent, debrief

Encoding LTM Baddeley (1966)

• Acoustically similar words, acoustically dissimilar, semantically similar, semantically dissimilar- 20 min interval- LTM
• Acoustic- no difference, Similar meaning- poor recall- LTM CODES SEMANTICALLY
• Lab- artifical (but used familiar words not just letters like Conrad), consent, debrief

Strengths & Weaknesses of MSM

• Important contribution to memory research- distinction between STM & LTM
• Too simple and inflexible- complexity of human memory- emphasis on how much info at one time- ingnores nature of infor e.g. remembering funny things or interesting things
• Artifical lab studies- not everyday life