Key: = Baddiel + Bradley (bear) = Baddeley = Positive impacts of anxiety & EWT, = H.M Christianson (Study by &Hubinette (1993) Milner 1966) = Negative impacts of Anxiety & EWT, Loftus 1979= Duration of LTM byBahrick et al 1975 = Eye witness testimonies – L(1979), Y/C, C/H(1993) = Baddeley and = Miller’s Hitch 1974 Working magic no. 7 Memory Model (1956)
Multi-store model – Atkinson and Shiffrin (1968):
Multi-store model of memory evaluation:• Distinguishes a • Simplistic – explains difference between the something complex in a capacity and duration of very simple manner. STM and LTM. • 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.
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 presentationFindings:- 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
Duration of LTM: Bahricket 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)
Working Memory Model: Baddeley and Hitch (1974)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 sourcesLimited capacity
Working Memory Model: Baddeley and Hitch (1974)• Evidence to support • Not much is known about phonological loop the central executive (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)
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 time2) 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.
Positive impacts of Anxietyand EWT:Yuille and Cutshall• 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 Anxietyand EWT: Christianson and Hubinette (1993)• 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.
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 answersAuthority 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.
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 hierarchies2. Encoding specificity principle3. 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 BRITAINEvidence:Bower et al (1969)-Learnt words-1st group used hierarchy technique = 65% of words correct-2nd group didn’t use hierarchy technique = 19% words correctInternally valid – extraneous variables were controlled as it was a LAB STUDYNot real life situation – may lack ecological validity
Encoding Specificity Principle –Tulvingand 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 BaddeleyAim: To investigate the relationship between learning and retrieval environmentsProcedure: 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 wordsFindings: The divers that learned and recalled in the same situation remembered the most wordsConclusion: The divers benefitted from recalling in the same environment as it held ‘retrieval cues’
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