Psychology - Memory

Coding - Short Term Memory (STM) codes acoustically (sounds) Long Term Memory (LTM) codes semantically (meaning).

Capacity - Jacobs - STM capacity 9.3 numbers and 7.3 letters on average.        Miller - STM capacity is 7 +- 2 items on average (increased by chunking).

Duration - Peterson and Peterson - STM duration 18-30 seconds without rehearsal.                                                                                                                        Bahrick et al. - LTM duration 70% accurate photo recognition after 48 years.

Memory Store Model (MSM) describes three separate memory stores, linked by processing.

Sensory Register (SR) - brief duration, high capacity, coding varies with sense.      Transfer SR to STM - only small amount of information attended to is passed on.

Short-Term Memory (STM) - Capacity is 5 to 9 items, duration is 18-30 seconds, coding is acoustic.                                                                                                                Transfer STM to LTM - occurs through maintenance rehearsal.

Long-Term Memory (LTM) - Capacity is unlimited, duration is up to a lifetime, coding is semantic.                                                                                                               Retrieval via STM.

3 Types of LTM;

Episodic Memory - Memories of events, e.g. whatyou had for lunch.                         Complex memories, time-sampled, conscious recall, about people and places.

Semantic Memory - Knowledge of the wprld (facts), e.g. what words mean.          Not time-stamped, less personal, hared knowledge.

Procedural Memory - Actions and skills, e.g. ride bike, how to 'do' things.            Recall without awareness or effort, hard to explain, automatic recall with practice.

Working Memory Model (WMM) - model of STM, its structure and function - four key components;

Central Executive (CE) - Very limited capacity, allocates subsystems/resources to tasks.

Phonological Loop (PL) -Auditory coding : 

• Phonological store holds words heard
• Articulatory process allows rehearsal.
• Capacity is about two seconds of what you can say.

Visuo-Spatial Sketchpad - visual/spatial coding:

• Visual Cache stores visual data.
• Inner scribe records objects in vision.
• Capacity is three or four objects

Episodic Buffer - Integrates data from other stores, time-sequencing, links to LTM.

Interference - Occurs when two pieces of imnformation conflict.                              Proactive interference - When an old memory disrupts a newer one.                        Retroactive interfence -  When a new memory disrupts an older one.                       Both types of interference are worse when the memories are similar.             

KEY STUDY -  McGeoch and McDonald

Procedure - participants learned two lists of items, 6 conditions, e.g. synonyms.      

Findings - recall of first list worse when second list similar.

Retrieval failure due to absense of cues. -  Cues stored at same time as memory, cues help access to memory.                                                                                              Encoding specifically principle (ESP) - Same cues at coding and retrieval aid recall (Tulving).                                                                                                                                     Some cues linked meaningfully - e.g. the letters 'STM' trigger recall of information.   Some cues not linked meaningfully - e.g. context information or emotional state.

KEY STUDY - Godden and Baddeley

Procedure - Divers learned/recalled words in same/different context (land/water).

Findings - recall best when context at learning and recall matched.