cognitive psychology - memory (psya1)
TRANSCRIPT
Memory:
Key:= Baddiel + Bradley
(bear) = Baddeley
= H.M (Study by Milner 1966)
= Duration of LTM by Bahrick et al 1975
= Miller’s magic no. 7 (1956)
= Baddeley and Hitch 1974 Working Memory Model
= Eye witness testimonies – L(1979), Y/C, C/H(1993)
= Negative impacts of Anxiety & EWT, Loftus 1979
= Positive impacts of anxiety & EWT, Christianson & Hubinette (1993)
Multi-store model – Atkinson and Shiffrin (1968):
Multi-store model of memory evaluation:
• Distinguishes a difference between the capacity and duration of STM and LTM.
• Simplistic – explains something complex in a very simple manner.
• Focuses too much on the structure of the model as opposed to the processes involved.
• ‘rehearsal’ is deemed the only way to move information from STM to LTM – maybe there’s another way.
Milner (1966) – H.M.
• Supports the MSM – as it shows that the LTM and STM are stored differently.
• Had brain surgery, which left him unable to recall things that had just happened.
• It was concluded that he couldn’t move memories into his long term memory.
Short Term memory…
Capacity of STM by Baddeley et al (1975):
Aim: To see if more people could remember more short words than long words in a serial recall test. So demonstrating that pronunciation times rather than the no. of items to be recalled determines the capacity of STM.
Procedure: - reading speed of ppt was measured- given 5 words on a screen- One set one-syllable words, one set multi-syllable words- Ppts were asked to write down 5 words in order immediately after presentation
Findings:- More short words were recalled than long words- Able to recall as many words as they could say in 2seconds- Strong + correlation between reading speed & memory spanConclusion: Immediate memory span represents the no. of items of whatever
length can be articulated in 2 seconds.
Duration of STM: Peterson & Peterson (1959)
Aim: To see how long STM lasts when rehearsal is preventedProcedure: - Ppts were briefly showed 3 letters (trigram)- Ppts were asked to count backwards to stop them rehearsing
the letters- After 3, 6, 9, 12, 15 and 18 seconds, they were asked to recall
the original 3 letters (in order)Findings:- 80% of trigrams (3 letters) were recalled after 3s- By 18s, less than 10% of trigrams could be recalledConclusion: When rehearsal is prevented, short term memory doesn’t last long
Encoding in STM: Baddeley (1966)
Aim: To explore the effects of acoustic & semantic encoding in STMProcedure: ppts divided into 4 groups, ones that heard:1. Acoustically similar words (map/mad/man)2. Acoustically dissimilar words (pen/day/few)3. Semantically similar words (big/large/grand)4. Semantically dissimilar words (hot/old/late) Findings: - 55% A.S. words were recalled- 75% of A.D words were recalled- Semantics (meaning) were similarConclusion:STM relies more on acoustics than their meaning
Long term memory…
Duration of LTM: Bahrick et al (1975):
Aim: To establish the existence of very LTM, seeing whether there’s a difference between recognition and recall.
Procedure: - investigators found old high school grads. Over 50-year period. IN AMERICA.- 392 grads. Were shown yearbook photos- 1 group – recalled names from memory (recall)- 2nd group – matched names to faces (recog.)
Findings:- Recall group: After 47 years, less than 20% accuracy- Recog. Group: After 47 years, accuracy @ 60%Conclusion:- People can remember certain types of info. For almost a lifetime- Long term memory is better in recog. than recall.
Encoding in LTM: Baddeley (1966)
Aim: To explore the effects of acoustic & semantic coding on LTMProcedure: ppts divided into 4 groups…1. Acoustically similar words (map/mad/man)2. Acoustically dissimilar words (pen/day/few)3. Semantically similar words (big/large/grand)4. Semantically dissimilar words (hot/old/late) - After 20 minutes, they were given another task to do, before having to
recall the words.Findings:- Recall 55% accuracy for S.S words- Recall 85% accuracy for S.D words- Recall was same for A.S and A.DConclusion:LTM is primarily semantically coded (opposite to STM!)
Miller’s magic number 7 (1956):
Miller found that people had a digit span of 7±2
Working Memory Model: Baddeley and Hitch
(1974)
Visual Episodic Language
Long term memory
Working Memory Model: Baddeley and
Hitch (1974)Central executive: Most important. Involved in decision making, and
problem solving. Flexible, and can process lots of informationLimited storage capacityPhonological loop:‘Inner ear’ – holds acoustic info. and ‘inner voice’ –
allows sub vocal repetition (by getting a ppt to say ‘the the the’ during a memory task prevents the phonological loop from working)
Visuo-spatial scratch pad:‘inner eye’, stores visual and spatial info.Sets up and manipulates mental images.Limited capacityLimits of the systems are independent(added in 2000) Episodic Buffer:Integrates information from different sources Limited capacity
Working Memory Model: Baddeley and
Hitch (1974)
Working Memory Model: Baddeley and
Hitch (1974)• Evidence to support
phonological loop (Baddeley 1975 – investigating the ‘word-length effect’)
• Evidence to support visuo-spatial scratch pad (Baddeley 1973 – ppts had to do a tracking task along side a letter imagery task, which they found difficult, proving the visuo-spatial is processed separately)
• Not much is known about the central executive
Eye-witness testimony (EWT):
‘An area of memory that investigates the accuracy of memory following an incident, and the type of errors that are commonly made in that situation’
Negative impacts of Anxiety and EWT: Loftus (1979)
Aim: To find out if anxiety during a witnessed incident affects the accuracy of later identification.
Procedure: Ppts were split into 2 groups:1. A low key discussion was overheard followed by a person coming out of the
lab with a pen, and grease on their hands.2. A noisy hostile exchange was overheard followed by a person emerging from
the lab with a paper knife covered in blood.Ppts in each situation were asked to identify the person who had emerged from
a line-up of 50 people.Findings: 1) The group that had sit. 1) were accurate 49% of the time 2) The group that had sit. 2) were accurate 33% of the timeConclusion:Ppts were too focused on the weapon to notice the person’s face.
• Interviewed 13 real-life witnesses, who’d seen a shooting
• Some witnesses were closer than othersInterviews showed that:- Witnesses gave accurate accounts several months later- Those closest to the shooting provided the most detail- Misleading questions had no effect on accuracy- Those who were most stressed provided the most
detailed accounts
Positive impacts of Anxiety and EWT: Yuille and Cutshall
• Questioned 110 witnesses, who had (between them) witnessed 22 genuine bank robberies.
• Witnesses who were more accurate, were bystanders (not threatened themselves)
• Their recall continued to be better, even after a 15 month period.
Positive impacts of Anxiety and EWT: Christianson and
Hubinette (1993)
Children and EWT Ceci & Bruck (1993):
Repeated questions – Young children are more likely to change their answers when asked a second time.
Encouragement to imagine – Young children are more likely to make up details.
Peer pressure – If a child feels pressured, it may affect their answers
Authority figures – Children may be more susceptible to misleading info. due to desire to please authority figures.
Leading questions:
‘Questions which are worded in such a way that they might make someone answer in a particular way’
- They’ve been found to affect EWT as they cause a bias in the answers.
Leading questions – Loftus (1974)
Aim: Seeing if leading questions distorted the accuracy of EWT.Procedure: 45 students watched a series of short traffic accidents,
and given a questionnaire after each one. Within each questionnaire, there was one ‘critical question’, which was ‘How fast were the cars going when they ____ eachother?’
Findings: Verb Average estimated speed
Smashed 41
Collided 40
Bumped 38
Hit 34
Contacted 31
Misleading info.:
Misleading info: The investigator slipping in words that wrongly implicate that something happened, when it didn’t.
Often, it makes a change in the ppts memory.
Misleading information – Loftus (1975) Barn
• 150 ppts a car accident• Divided into two groups• 1st group: Asked 10 questions that were consistent with the
film.• 2nd group: Asked 9 questions that were consistent, and one
question that was misleading: ‘How was was the sports car going when it went past the barn’ (there was no barn!)
• One week later… Ppts were asked ‘did you see a barn?’• 1st group: 2.7% said yes• 2nd group: 17.3% said yes• Loftus concluded that the barn was added to their memories
from due to the information from the misleading questions.
Cognitive Interviews – Geiselman et al (1985):
• 4 techniques: 1. Context reinstatement – weather, smells.2. Reverse order.3. Detail – report everything.4. Change of perspective.• Good search to support it (Geiselman 1988)• Officers would have to be re-trained which
would be time consuming and costly.
CORP =contextorderreport
perspective
Cog. Interview – Geiselman (1988)‘effectiveness of CIT in lab setting’
• 89 students shown crime video.• Some interviewed with Standard Interview, some by
CIT.• Those interviewed by CIT showed higher recall than
those interviewed with Standard Interview.• Lab study• Ecological validity – low, due to being shown a video
of a crime. Wouldn’t necessarily work IRL settings.• All the people shown were students. Therefore not
representative of the whole popualation.
Cog. Interview – Fisher et al (1989)
‘effectiveness of CIT in real-life setting’
• Detectives, Florida, USA, trained in CIT. • 47% increase in info. Produced by witnesses
compared to pre-training.• CIT produces more information than Standard
Interview.• Ecologically valid – uses real life settings.• Ethnocentric – All from Florida.
Improving memory:
1. Organisation hierarchies
2. Encoding specificity principle
3. Using mnemonics - inc. Method of Loci.
Organisation hierarchies:
I’m in my HOUSE – which is in NORWICH – Which is in ENGLAND – which is part of GREAT BRITAIN
Evidence:Bower et al (1969) -Learnt words-1st group used hierarchy technique = 65% of words correct-2nd group didn’t use hierarchy technique = 19% words correct
Internally valid – extraneous variables were controlled as it was a LAB STUDYNot real life situation – may lack ecological validity
Encoding Specificity Principle – Tulving and Thompson (1973):
• When we learn things, we encode them with links to the context in which we learnt them.
• The context is classed as a ‘retrieval cue’ which helps to recall information stored in LTM.
• This may explain why our recognition is better than our recall memory
Using mnemonics:
‘Techniques for improving memory based on encoding information in special ways so that a strong memory trace is established along with effective cues’
E.g. ‘Richard Of York Gave Battle In Vain’ ‘Dear Keith Please Could Our Family Go Somewhere’
Method of loci:
• Assigns aspects of info. to familiar images in a sequence.
Evidence: Paivio 1971 - He suggested that words & images were processed separately.
- Meaning they are ‘double encoded’, therefore deeper level of processing
Learning and retrieval – Godden and Baddeley
Aim: To investigate the relationship between learning and retrieval environments
Procedure: Divers were given 40 unrelated words, either on land, or 15 feet under water.Half of the divers switched environments before they tried to recall the words
Findings: The divers that learned and recalled in the same situation remembered the most words
Conclusion: The divers benefitted from recalling in the same environment as it held ‘retrieval cues’