Memory

Alan Baddeley 1966

Investigate coding in STM and LTM

Method:

• 4 groups of pts. asked to remember different lists of words
  • Accoustically Similar
  • Acoustically not similar
  • Semantically similiar
  • Semantically not similar

Results:

• When asked to recall immedietley, did worse with Accoustically Similar words
• When asked to recall after 20 mins, did worse with Semantically Similar words

Conclusion:

Encoding in LTM is semantic

Evaluation:

• Low ecological validity ( lab experiment )
• Control over IV and extraneous variables
• Establish cause and effect - STM and LTM use different types of coding

George Miller 1956

Testing the capacity of the STM

Method:

Digit Span and Chunking

Evaluation:

• May have overestimated the capacity of STM
• Other research shows 5 items rather than 7 items

Peterson and Peterson

Test how long STM can last without rehearsal

Method:

• 24 undergraduate students, each taking part in 8 trials
• Each student given a consonant syllable and a 3 digit number
• Asked to count back from number until told to stop
• After intervals of 3,6,9,12,15 and 18 seconds, pts. asked to stop counting an repeat syllable

Results:

• Pts. able to recall 80% of syllable after 3 seconds
• After 18 seconds, less than 10% could be recalled

Conclusion:

If rehearsed, recall is better in STM

Evaluation:

• Low ecological validity, lab experiment
• Established cause and effect
• Results support claims/ other results
• Too simple

Bahrick Et Al

Investigate the length of time memories can be retained in LTM

Method:

• Interviewed high school student graduates in USA over 50 years
• 400 students shows set of photos and a list of names
• They had to identify their class mates and give their names

Results:

• Pts. 90% correct 15 years after graduation

• 80% correct on names after 48 years
• 70% correct on faces after 48 years

Conclusion:

LTM is lifelong

Evaluation:

• High ecological validity
• Low control over extraneous variables -  conclusion can not be valid.

Multi Store Model of Memory (MSM)

• Made up of 3 stores: Sensory Register, STM and LTM
• Describes how information is transferred from one store to the other, how it is remembered, how it is forgotten and also how it is recalled.

Sensory Register:

• Stores information from each of the 5 senses
• Has a huge Capacity
• Information is kept for less than half a second

STM:

• limited capacity store ( 7 +/- 2 ) Supported by Miller
• Stays in the STM as long as it is rehearsed
• Stays for around 18-30 seconds. Supported by Peterson and Peterson
• Stored Accoustically. Supported by Baddeley

LTM:

• Potentially unlimited capacity. Supported by Bahrick Et Al
• Stored Symantically. Supported by Baddeley
• Transferred back to STM when it needs recalling (Retrieval)

Evaluation:

• Supported by research and studies that show STM and LTM are seperate stores / different
• The MSM is too reductionist
• Does not support other studies that say different kinds of rehearsals are needed
• Supported by the Primacy and Recency effect

Types of LTM

Episodic Memory - Personal experiences ( e.g. holiday or event )

Semantic Memory - Facts and knowledge ( e.g. 2+2=4 , capital of England is London )

Procedural Memory - How to perform things ( e.g. riding a bike, horse, locking the house )

Evaluation:

• Brain scans support the idea of different types of memory stores

The Working Memory Model (WMM)

Representation of STM and suggests it is a dynamic process of different types of information using sub-units coordinated by a central decision making system

Central Executive:

• Monitors incoming data, makes decisions and allocates slave sytems to tasks
• Limited Capacity

Phonological Loop:

• 1st Slave System, deals with auditory information
• Divided into, Phonological Store ( words you hear ) and Articulatory Process ( rehearsal )
• Capacity of 2 seconds

Visuo-spatial sketchpad:

• 2nd Slave System, stores visual and spatial information
• Divided into Visual Cache ( stores visual data ) and Inner Scribe ( arrangement of objects )

• limited Capacity of 3-4 objects

Episodic Buffer:

• 3rd Slave System
• Temporary store of visual, spatial and verbal and records events that happen
• Limited capacity of 4 chunks
• Links to the LTM

Evaluation:

• Patient damaged only 1 component but still could use others - supports WMM
• Psychologists know very little about the Central Executive
• Supported by experiements / studies that show seperate components

Baddeley and Hitch 1974

Investigate whether pts. can use different parts of Working Memory at the same time

Method:

• Pts. given 2 taks simultaneously
• Task 1 = Occupied the Visuo-spatial Sketchpad and Phonological Loop
• Task 2 = Occupied the Articulatory Loop

Results:

• Task 2 completed slower by pts ( only one/ the same component - articulatory loop )
• Task 1 was completed quicker ( two components )

Conclusion:

• Doing 2 tasks the involve the same component causes difficulty, VICE VERSA
• Support the WMM -  shows that STM must use different Slave Systems and that tasks are easier when using 2 different components

Forgetting - Interference

Interference: Forgetting because one memory blocks another

Proactive Interference: Older memories affect newer memories ( e.g. forgetting new names )

Retroactive Interference: New memories affect old memories ( e.g. forgetting old names )

McGeoch and McDonald 1931

Discover whether interference is worse when the memories are similar, studied Retroactive Interference

Method:

• Changed the amount of similaritity between two sets of material
• Pts. had to learn a list of words until they could remember them with 100% accuracy
• They then learned a new list

• Group 1 - Synonyms 
• Group 2 - Antonyms ( Words with the opposite meaning )
• Group 3 - Words not related to the original ones
• Group 4 - Nonsense syllables
• Group 5 - 3 digit numbers
• Group 6 - No new list, pts. just rested

Findings:

Synonyms were used as interference material, causing the lowest number of items to be recalled

Evaluation:

• Interference well supported by evidence and experimental findings
• Learning a list of words has low ecological validity

Explanation for forgetting: Retrieval Failure

Retrieval Failure - Occurs when we dont 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 to access a memory. May be External (environment) or Internal (mood etc.)

Tulving (ESP) 1983

Reviewed research into retrieval failure and summarised the pattern called Encoding Specificity Principle. This states that if a cue helps us to recall information it has to be present at encoding and at retrieval. If the cues are different, we will end up forgetting the information.

External Cues - Godden and Baddeley 1975

(Scuba Diving Experiment)

Method:

• 1 - learned words on land and recalled on land
• 2 - learned words on land and recalled underwater
• 3 - learned words underwater and recalled on land
• 4 - leanred words underwater and recalled underwater

Findings: 

• Recall was 40% lower in the non-matching conditons
• Cues different from encoding and recall - Supports ESP and Tulving

Internal - Carter and Cassaday 1998

Method: Gave pts. anti-histamine drugs. They made pts. feel drowsy

• 1 - learning words ON drug and reacalled when ON drug
• 2 - learning words ON drug and reacalled when NOT on drug

• 3 - learned words when NOT on drug and recalled when ON drug
• 4 - learned words when NOT on drug and recalled when NOT on drug

Findings:

Recall lower when conditions were different -  supports ESP and Tulving

Evaluation:

• Studies and experiment support the Retrieval Theory of Forgetting
• The differences between conditions are not always very different -  less forgetting

Factors effecting Eye Witness Testimony (EWT)

Misleading Information: Incorrect info given to eyewitness after the event

Leading Question: A question leading the eyewitness to a desired answer

Post Event Discussion: Witnesses discussing what they have seen , influencing testimony.

Loftus and Palmer 1974 - leading questions experiment

Method:

• 45 students shown 7 clips of an RTC
• After each clip, pts. asked to:
  • Write and account of what they had seen
  • Answer questions about the accident

"About how fast were the cars going when they _________ each other?"

Findings:

Evaluation:

• High degree of control over the IV
• More control over extraneous variables -  increases reliability and experimental validity
• Accidents were not real, low ecological validity

Why do leading questions affect EWT?

Response bias explanation - Wording influences the answer

Substitute explanation - Certain words change their memory of the incident

Post Event Discussion - Gabbert Et Al 2003

Method: 

• In pairs, pts. watched a video of the same crime but filmed from different points of view
• Both pts. then discussed what they had seen before individually recalling them

Findings:

• 71 % of pts. recalled things they did not see but instead heard in the discussion
• 0% of pts. recalled the event in the control group, where a discussion did not take place

Conclusion: Witnesses go along with each other to win either social approval or because they believe the other witness to be correct and themselves wrong

Evaluation:

• Experiment has good ecological validity becauase they are real world scenarios
• Research can help legal systems and authorities
• Extraneous variables ( e.g. Age ) can affect the recall of events

Factors affecting EWT - Anxiety

Anxiety - Emotional state, worried thoughts and tensions brought on by stressful situations

Anxiety has a Negative effect on recall - Johnson and Scott 1976

Method:

• Pts. believed they were going to take part in a Lab study
• Whilst sitting in a waiting room, the pts. heard an argument next door
• In the Low Anxiety condition a man walked through the waiting area with a pen and grease on his hands
• In the High Anxiety condtion the pts. heard glass smashing and a man walking through the waiting room with a paper knife covered in blood

Findings:

• Pts. later identified the man in a set of 50 photos
• 49% of pts. identified the man who they had seen holiding a pen
• 33% of pts. identified the man who they had seen holding a knife 
• Tunnel Theory argues that the witness focuses on the weapon because of anxiety

Anxiety has a Positive effect on recall - Yullie and Cutshall 1986

Method:

• Conducted on a REAL LIFE SHOOTING in Canada,  Shop keeper shot dead a thief
• Of 21 witnessed, 13 agreed to take part in the study
• Interviews help 4-5 months after the shooting and compared with the original interviews at the time of the shooting
• Accuracy was determined by the number of details reported in each account
• Pts. also asked how stressed they felt at the time of the shooting

Findings:

• Pts. were very accurate and little change from original interviews
• Pts. who said they were very stressed at the time had best recall
• High levels of stress - 88% accurate
• low levels of stress - 75% accurate

Evaluation:

• Weapons focus is related to suprise and not anxiety
• Interviewing Pts. after event meant there is no control over Post Event Discussion - Extraneous Variables
• Creating Anxiety in Pts. has Ethical Issues
• Are lots of experiments really needed? or can people just compare research ( less psy. harm )

Improving EWT - The Cognitive Interview

Cognitive Interview - Method of interviewing eyewitnesses to help them be more accurate.

Report Everything - Witnessed encouraged to include every single detail

Context Reinstatement - Witnesses return the original crime scene in their mind

Recall in Reverse Orde - Witnesses ""

Recall from a Changed Perspective - Witnesses recall from other people's perspective

Enhanced Cognitive Interview (ECI)

ECI:

• Interviewer needs to know when to establish eye contact and when not to
• Reducing Anxiety
• Minimising Distractions and allowing witnesses to speak slowly and ask questions

Cognitive Interview Evaluation:

• Time consuming
• Using multiple techniques of the CI produced better recall