Models of memory

memory model definition

a representation of how memory would work in the brain. A conceptual framework to understand it.

Multistore model of memory diagram

• senses —> sensory register —> STM <—> LTM

• each component stores,encodes and processes information in a different way but they operate simultaneously + interact

sensory register capacity,duration + encoding

• capacity - very large/almost unlimited

• duration - 0.3-4s → 0.5s

• encoding - echoic + iconic

Short term memory capacity,duration + encoding

• capacity - 5-9 items

• duration - 18-30s

• encoding - acoustic

Long term memory capacity,duration + encoding

• capacity - unlimited

• duration - lifetime (ranges from hours to life time)

• encoding - semantic

encoding definition

the form information takes when it is stored in the brain

serial position effect

• the effect an item’s position on a list has on how well it is recalled. ​

• primacy effect : items at the start of the list are remembered well as they are rehearsed the most

• recency effect : items at the end of a list are remembered well as they are still in the STM

why do we forget 

• decay - if we don’t rehearse/retrieve memories for a long time they will be lost

• displacement : STM has a limited capacity and so when new information comes in some is forgotten if not rehearsed

• interference : we forget because memories interfere with and disrupt one another.

Peterson and Peterson Aim

to investigate the duration of short term memory

Peterson and Peterson procedure

• 24pp (psychology students)

• lab experiment

• pp were shown trigrams one at a time

• after pp were shown trigram they had to count backwards in 3’s or 4’s from a specified random digit until they were shown a red light

• trigrams then had to be recalled after intervals of 3,6,9,12,15 and 18 seconds

IV + DV of Peterson + peterson

• IV- time interval when pp were counting (preventing rehersal)

• DV - number of correct trigrams recalled 

Peterson + Peterson findings

• longer each pp had to count backwards the less accurately they were able to recall the trigrams

• 3s - 80% correctly

• 6s - 50%

• 18s - less than 10%

• STM has a short duration of 18s

types of long-term memory

• implicit memory → procedural/ classically conditioned memory

• explicit memory → semantic/episodic memory

implicit memory

• does not require conscious awareness

• procedural memory : motor skills + actions

• classically conditioned memory : reflexive responses learnt through association of two stimuli (UCS and CS).​

explicit memory

• memories we have conscious awareness of (we actively retrieve + think of them)

• episodic - memories we personally experience

• semantic - memory of facts and figures and general knowledge ​

Measurement - evaluating Multi store model

• Strength : supported by controlled lab experiments with standardised procedures to measure memory which allow for replication + reliability

• Limitations :

• the tasks used often lack ecological validity → may not reflect how memory works in real life settings

• Measuring the duration and capacity of memory stores may oversimplify a complex and interactive cognitive process.​

Working memory model

• more developed version of MSM

• short-term memory is renamed to working memory

• WMM distinguishes between different short term memory stores

central executive (CE)

• controls slave systems by determining how resources will be allocated

• information comes from LTM or sensory memory

• very limited capacity (about 4 chunks of info which are stored in the episodic buffer)

• allows us to switch attention between different inputs of information. ​

Phonological loop (PL)

• 2 parts - Articulatory control system, Phonological store

• Limited capacity of 2 seconds worth what you can say out loud. 

• Phonological loop - (inner ear) → holds the sound/words you hear

• articulatory control system - (inner voice) → words maintained by repetition that are heard or seen. 

Visuospatial sketchpad (VSS)

• temporary storage + manipulation of visual and spatial information.​

• VSS is important for tasks involving visual imagery, spatial reasoning and navigation.

Episodic Buffer (EB)

• temporary store of information

• links working memory to LTM

• limited capacity of 4 chunks

• maintains a time sequence of info

Strengths of WMM

• brain scans show that different parts of the brain are active during verbal vs visual tasks → different parts of memory for visual + verbal tasks

• model explains the execution of everyday tasks such as reading using the PL and navigating using the VSS

Weaknesses of WMM

• model is complex → only one component of WMM can be tested at a time

• does not explain memory distortion or the role of emotions in formation of memories

• reductionist → looks only at STM and does not factor in SR and LTM.

Cognitive load theory

• an educational theory that explains how the brain processes information during learning

• focuses on the limitations of working memory. ​

what does the cognitive load theory suggest

• working memory has a limited capacity + duration

• Long term memory has an unlimited capacity

• learning involves transferring info from working memory to LTM

• learning is hindered if too much info is presented at once → cognitive load

types of cognitive load

• intrinsic load

• extraneous load

• germane load

intrinsic load

• The complexity of the material itself.

• Intrinsic load can't be eliminated but can be managed by breaking material into smaller steps.​

Extraneous load

• The way info is presented; unnecessary effort caused by poor instructional design.

• Extraneous load should be minimized by presenting info clearly and in an integrated way.​

Germane load

• The effort involved in processing, constructing, and automating schemas.

• Germane load is desirable—it's the "good" load that supports deep learning.