Psychology - Memory

Short-term memory (STM)

Short-term memory (STM)

The limited capacity memory store. In STM, coding is mainly acoustic, capacity is 7 +/- 2 and duration is 18 seconds

Long-term memory (LTM)

The permanent memory store. In LTM, coding is mainly semantic, it has unlimited capacity and can store up to a lifetime

Coding

The format in which information is stored in the various memory stores

Capacity

The amount of information that can be held in the memory store

Duration

The length of time information can be held in memory

Acoustic

The perception and retainment of of sound

Semantic

General facts

Digit span

A measure of verbal short term and working memory

Chunking

Grouping sets of digits and letters into units

Multi-store model (MSM)

A representation of how memory works in terms of three stores called the sensory register, STM and LTM. It also describes how information is transferred from one store to another

Sensory Register

The memory store for each of our five senses. The capacity involves millions of receptors and has a duration of 0.5 seconds

Maintenance rehearsal

The process of repetition to retain memories in the STM

Episodic memory

A LTM memory store for personal events, memories of events, people, objects, places and behaviours. These memories of recalled consciously

Semantic memory

A LTM memory store for our general knowledge. These memories are called consciously

Procedural memory

A LTM memory store for our knowledge of actions including learnt skills. These memories are usually recalled unconsciously

Working memory model (WMM)

A representation of STM. It suggests that STM is a dynamic processor of different types of information using sub units coordinated by a central decision-making system

Central executive (CE)

The component of the WMM that coordinates the activities of the three sub systems in memory. It allocates processing resources to those activities

Phonological loop (PL)

The component of the WMM that processes information in terms of sound. This includes both written and spoken material. It’s divided into the phonological store and the articulatory process

Visuo-spatial sketchpad (VSS)

The component of the WMM that processes visual and spatial information in a mental space

Episodic buffer (EB)

The component of the WMM that brings together material from the other subsystems unto a single memory rather than seperate strands. It also provides a bridge between working memory and LTM

Phonological store

Stores words you hear

Articulatory process

Allows maintenance rehearsal to keep the sounds in working memory

Visual cache

Stores visual data

Inner scribe

Records the arrangement of objects in the visual field

Interference

Forgetting because one memory blocks another, causing one of both memories to be distorted or forgotten

proactive interference (PI)

Forgetting occurs when older memories, already stored, disrupt the recall of newer memories. The degree of forgetting is greater when the memories are similar

Retroactive interference (RI)

Forgetting occurs when newer memories disrupt the recall of older memories already stored. The degree of forgetting is similar when memories are similar

Retrieval failure

A form of forgetting. It occurs when we don’t have the necessary cues to access memory. The memory is available but not accessible unless a suitable cue is provided

Cue

A trigger of information that allows us access to a memory

Encoding specificity principle (ESP)

For a cue to be helpful it has to be present at time of learning and time of retrieval

Context-dependent forgetting

Recall depends on external cues

State-dependent forgetting

Recall depends on internal cues

Eyewitness testimony (EWT)

The ability of people to remember the details of events which they have observed. Accuracy can be affected by factors such as misleading information and anxiety

Misleading information

Incorrect information given to an eyewitness usually after the event. It can take many forms such as leading questions and post-event discussion

Leading questions

A question which suggests a certain answer due to phrasing

Post-event discussion (PED)

Occurs when there is more than one witness to an event. Witnesses may discuss what they have seen with co-witnesses or with other people which may influence others recall of the event

Anxiety

A state of emotional and physical arousal. Although a normal reaction to stress, it can effect accuracy of detail in EWT

Tunnel theory

People’s memory is enhanced on central events

Yerkes-Dodson law

The relationship between task accuracy and stress

Cognitive interview (CI)

A method of interviewing eyewitnesses to help them retrieve more accurate memories. It uses four main techniques: report everything, reinstate context, reverse the order and change perspective

Enhanced cognitive interview (ECI)

Additional elements to the CI based around social dynamics: minimising distractions, eye contact and open-ended questions

Baddeley - Coding Study

• 4 groups (acoustically similar, acoustically dissimilar, semantically similar and semantically dissimilar)

• Lists were handed out for each group and results showed STM is worse acoustically similar and LTM is worse with semantically similar words

• Suggests coding is done acoustically in STM and semantically in LTM

Jacobs - Capacity (Digit Span)

• Researcher reads out 4 digits at a time and the participant then recalls these (little issue)

• Digit span increases until participant struggles

• Digit mean is is 9 and letter span 7

Miller - Capacity (Chunking)

• Theorised capacity is 7 +/- 2 in STM

• people could recall 5 words as easily as 5 letters through chunking

Peterson and Peterson - Duration of STM

• 24 students with 8 trials each

• given an consonant syllable (YCG) and a 3-digit number to count backwards from (stopping rehearsal)

• Time increments for countdown in each trial (3, 6, 9, 12 seconds)

• 3 seconds = 80% accuracy

• 18 seconds = 3% accuracy

• Suggests that STM is approx. 18 seconds unless rehearsed

Bahrick - Duration of LTM

• 392 American participants

• High school yearbooks used for photo-recognition, name recall and free recall

• Within 15 years of graduation photo recognition was 90%, 48 years 70%

• Within 15 years free recall was 60% and 30% after 48 years

Atkinson and Shiffrin

Developed the multi-store-model (MSM)

Case study - HM

• Epileptic and underwent removal surgery on the hippocampus

• Damaged STM and destroyed LTM

• Procedural memory was able to improve (part of hippocampus was left)

Tulving - LTM Stores

• found the MSM to simplistic for LTM

• Created three memory store types episodic, semantic and procedural

Case Study - Clive Wearing

• Viral infection resulted in retrograde amnesia

• Permanent damage to LTM and STM of a few seconds

• Procedural and semantic memory remained intact and episodic was destroyed

Buckner and Peterson - Memory Store Placements

• Semantic memory was on the left side of the prefrontal cortex

• Episodic memory was on the right side of the prefrontal cortex

Baddeley and Hitch - The Working Memory Model

• Created the Working Memory Model

• An explanation of how one aspect of memory is organised and its function

• Consists of four main components - all qualitatively different in terms of coding and capacity

Baddeley - Episodic Buffer

• Added the episodic buffer to the WMM in 2000

• A temporary store for information which maintains time sequencing

• Can be viewed as the storage component of the CE but has a limited capacity of about four chunks

Case Study - KF

• After a brain injury KF had poor STM ability for auditory information but could process visual normally

• KF’s phonological loop were damaged but his visuo-spatial sketchpad was intact

• Supporting evidence of seperate visual and acoustic stores

Baddeley et al - Dual Performance Task

• Participants carried out visual and verbal tasks at the same time, performance was similar on each when done separately

• Performance declined when tasks were of the same category as a result of competition between the same sub-system

McGeoch and McDonald - retroactive interference

• Tested by changing the amount of similarity between two sets of material

• Participants had to learn a list of 10 words with 100% accuracy and then groups (6) had to learn another list

• Synonyms, antonyms, unrelated words, consonant syllables, 3-digits and no list

• The most similar material was worst recall showing that interference is strongest with similar information

Baddeley and Hitch - RW Interference

• Asked rugby players to recall the names of the teams they had played against during the season

• Players played for the same time interval but the number of games varied due to injury

• People who played the most had the poorest recall - provides validity to the theory of interference

Tulving and Psokta - Cues in Interference

• Gave participants a list of words organised into categories - recall average was 70% for first list but progressively got worse (proactive interference)

• At the end, the participants were given a cued recall test and recall rose again to be about 70%

• This shows interference causes a temporary loss of accessibility to materials

Coenen and Luijtelaar - Retrograde Facilitation

• Gave participants a list of words and later asked them to recall the list, assuming the intervening experiences would act as interference

• Found that a list of words learnt when on diazepam, recall was poor but if learnt before recall was better

• Meaning the drug improved )facilitated) recall of material learned before

Godden and Baddeley - Context-Dependent Forgetting

• Studies deep-sea divers who work underwater to see if training on land helped or hindered

• Divers learnt a list of words either underwater or on land and asked to recall in either one of the conditions creating four groups

• Accurate recall was 40% lower in non-matching conditions concluding that the external cues available at learning were different from ones available at recall leading to retrieval failure

Canter and Cassaday - State-Dependent Forgetting

• Gave antihistamines to participants making them drowsy

• Participants had to learn a lost of words and passages of prose and recall the information creating four conditions

• When mismatched between internal state at learning and recall memory was significantly worse

Loftus and Palmer - Leading Questions

• Arranged 45 participants to watch film then clips of car accidents and then asked about the accident

• In the critical question participants were asked to describe how fast the cars were travelling - verb differed

• Hit, bumped, contacted, collided and smashed

• Contacted mean was 31 mph whilst smashed was 41 mph

• This creates bias within EWT

Loftus and Palmer - Response bias Explanation

• Leading questions can then alter a person’s memory of the clip

• Shown because participants who originally heard smash were later more likely to report broken glass (there was none)

• The critical verb then altered the incident to the participant

Gabbert - Post Event Discussion

• Studied participants in pairs, each participant watched a video of a crime from different POVs

• Both participants then discussed what they had seen before individually being tested on recall

• 71% repeated aspects as a result of discussion - evidence of memory conformity

Johnson and Scott - Weapon Focus and Anxiety

• Participants believed to be part of a lab study while in the low anxiety group participants heard a casual conversation and saw a man walk past with a pen and grease on him

• High anxiety condition heard an argument accompanied by breaking glass and a man walked out carrying a knife covered in blood

• Participants later picked out the man from a set of 50 photos, 49% recognised the man carrying a pen and 33% recognised the knife

• As a result weapon focus could alter memories of the central event

Yuille and Cutshall - positives of Anxiety

• A study of an actual gun shooting when a shop owner shot a thief dead

• There were 21 witnesses - 13 took part they were interviewed 4-5 months after the incident and these interviews were compared with the original police interviews

• Witnesses were asked to rate their stress levels at the time of the shooting and if they had any emotional distress since

• Witnesses experienced little change in interviews over 5 months even if accuracy of details slightly declined

• Those who reported higher stress are usually more accurate

Fisher and Geiselman - The Cognitive Interview

• Created an improved police EWT method

• The four main techniques report everything, reinstate the context, reverse the order and change perspective

Fisher - The Advanced Cognitive Interview

• Developed additional elements to the cognitive interview focuses on the social dynamics of interaction

• Includes ideas on reducing anxiety and distractions using open-ended questions

Kohnken - CI Effectiveness Meta-Analysis

• Studied 55 studies comparing the CI to standard police interview

• The CI gave a 41% accuracy increase as opposed to the police interview

• Only 4 studies showed no difference