4.1.2 - Memory

• STUDY Sensory register- Sperling - Capacity


  pps were shown with 3 rows of 4 letters for 50 milliseconds.

  When asked to recall the whole grid they only managed to recall 4 or 5 letters. When a particular row was indicated (by tone), pps could recall an average of 3 items no matter which row had been selected.

  Therefore almost the whole grid was held in their sensory register, but some decayed before it could be recalled

  • SR has a high capacity but limited duration
• STUDY Sensory register- Sperling - Duration



  Duration: Information decays within about 2 secs (or less). If the delay between presentation of grid and tone was increased to 1 sec, ps could only remember 1 letter on average 

  • SR has a high capacity but limited duration
• STUDY STM -Jacobs - Capacity




   Digit span test.

   On average pps could repeat back 9.3 numbers and 7.3 letters, immediately after they were presented.  

  Miller’s Magic number 7: literature review of research into the capacity of the STM. Miller found that the capacity of STM is roughly ‘seven plus or minus two’ items, but can be improved by chunking information
• STUDY STM -Peterson and Peterson: Duration




   24 undergraduates, 8 trials.

  Given a nonsense trigram to remember (e.g. ZFB) and had to count backwards in threes from a large three-digit number (to prevent rehearsal). 

  On each trial they were told to stop counting backwards after a different amount of time (called a retention interval)

  • 3,6,9,12,15 or 18 seconds.

  After 3 seconds about 80% of trigrams were recalled correctly.

  After 18 seconds average recall fell to about 3%.

  The STM memory fades/decays under 30 seconds without rehearsal
• STUDY STM & LTM - Baddeley: Encoding


   Independent groups design, pps given acoustically similar or dissimilar words or semantically similar or dissimilar words to recall in the correct order.

  Immediate recall (STM recall) was worse with acoustically similar words. Recall after 20 minutes (LTM recall) was worse with semantically similar words. It seems there was acoustic confusion in the STM and semantic confusion in the LTM.

  The pattern of confusion between similar words suggests the STM is most likely to rely on acoustic coding and the LTM on semantic ending.
• STUDY LTM - Bahrick: Duration





  392 American pps.

  High school yearbooks obtained. Recall tested in various ways including: 

  1. Photo-recognition test consisting of 50 photos, some from the pps’ yearbook

  2. Free recall test, pps listed all the names of their graduating class.

  15 years after 90% accurate in photo-recognition.

  48 years after graduation recall was about 70% accurate in photo-recognition Free recall was less accurate (60% then dropping to 30%)
• Short term memory -STM

  Capacity: 7+/-2 items  (5-9)

  Duration: 18- 30 seconds (but longer if information is rehearsed)

  Encoding: Mainly acoustic -sounds we hear
• Long term memory -LTM 


  Capacity: Potentially unlimited

  Duration: Potentially unlimited (up to a lifetime)

  Encoding: Mainly semantic (in terms of meaning)
• Sensory register - SR

  Capacity: High (e.g. more than 1 million cells in one eye storing data)

  Duration: Up to about  2 seconds

  Encoding: Modality specific-depending on the sense- visual, auditory etc…
• Multistore model -MSM

  
• MSM -AO3

  +Supporting research, Baddeley existence of separate memory stores

  -Issues with supporting research, lack of mundane realism, random words/consonants, may suggest the MSM lacks external validity, may not explain how memory works in everyday life with meaningful stimuli, inferred by the wealth artificial research to support it 
• MSM -AO3

  -Tulving suggest 3 types of LTM 

  -WMM suggests a more complex model of the STM and KF

  -poor auditory STM ability, intact visual

  -Only explains one type of rehearsal, elaborative rehearsal is also needed
• Working Memory Model - WMM

  
• WMM -AO3

  + Braver et al, pps given a task involving the CE (‘n-back task’ which involves judging whether a current letter was seen in a previous trial),activity in the PFC increased as the task became harder

  + Supporting research. Patient KF had poor STM ability for verbal info but could process visual info
• WMM -AO3

  + Support for the VSS Baddeley et al (1975) found pps had more difficulty doing two visual tasks (tracking a light and describing the letter F) than doing a task a visual and verbal task at the same time.

  - Lack of clarity of the CE, e.g. unclear how it allocates resources to slave systems. May have subcomponents 
• Types of LTM -AO1

  Tulving argued that the MSM of memory was too simplistic proposed that there are three LTM stores, containing different types of information: 

  Episodic- events from our lives, like a diary, they are time-stamped and include several elements, such as people, places, objects, emotions and behaviours. 

  Semantic- world knowledge/facts, not time-stamped and less personal

  Procedural - skills/how to do things 
• Types of LTM -AO1

  Episodic and semantic are declarative (explicit)- requires conscious recall

  Procedural is non-declarative (implicit)- does not require conscious recall
• Types of LTM- AO3

  + Supporting case studies. HM 

  Could not recall stroking a dog half an hour before but did not need the concept of a dog explained to him. CW episodic damaged but semantic and procedural in tact (play piano).

  -Issues with case studies, lack of control (of precise are of brain damage) and difficult to generalise
• Types of LTM- AO3

  + Brain scan evidence. Tulving episodic and semantic memories were both recalled from the pre-frontal cortex; semantic in the left side and episodic in the right side

  -Semantic and procedure overlap and may be one type of LTM-declarative 
• Interference - AO1

  Two pieces of information conflict with one another, resulting in forgetting of one or both, or in some distortion of memory.

  Two types:

  Pro-active interference(PI): Forgetting occurs when older memories (prior), already stored disrupt the recall of newer memories 

  Retro-active interference (RI): Forgetting occurs when newer memories (recent), disrupt the recall of older memories already stored. Most likely when info is similar 
• Interference - AO1 -Supporting research

  •McGeoch and McDonald- word list, then 2nd  list e.g. consonant syllables, 3-digit numbers, synonyms, then they’d recall the 1st list.  Recall of the original list was worse in the condition with synonyms- showing the effect of similarity in RI 
• Interference - AO3

  +Supporting research McGeoch and Mcdonald recall was better for very different stimuli e.g. digits and worse for similar info e.g. synonyms 

  -Lack of mundane realism E.g. word lists and consonants
• Interference - AO3

  + Real-life studies. Baddeley and Hitch, those who played more games had less accurate recall of team names and this was attributed to interference. 

   

  -Time allowed between learning, quite short e.g. 2 tasks within 20mins. Conclusions may lack external validity- role of interference may be exaggerated
• Retrieval failure - AO1


  Forgetting occurs due to insufficient cues.

  ESP- cues help retrieval if the same cues are present at encoding (when we learn the material) and at retrieval (when we are recalling it). 
• Retrieval failure - AO1

  Context dependent forgetting: when memory retrieval is dependent on an external/environmental cue

  State dependent forgetting: When memory retrieval is dependent on an internal cue (e.g. be feeling upset, happy or being drunk)

   

  Supporting research:

  •Godden and Baddeley-underwater/land•Carter and Cassidy –anti-histamine/not
• Retrieval failure - AO3

  +Supporting research Godden and Baddeley

  +Applications to the cognitive interview e.g. reinstate context

  -Context effects not very strong in real life. Learning and recalling in another room, environments not different enough 
• Retrieval failure - AO3

  -Context effects only occurs when memory is tested in certain ways.  Godden and Baddeley found no context effects when using a recognition test instead of recall

  -ESP unfalsifiable and leads to circular reasoning 
• EWT Misleading information - AO1

  Misleading information: incorrect information given to the eyewitness usually after the event. It can take many forms e.g. leading questions and post-event discussion between co-witnesses
• EWT Misleading information - AO1 - Leading questions: Loftus and Palmer

  Leading questions: Loftus and Palmer

  45 American students watched 7 film clips of car accidents and were then given questionnaires about the accident. In the ‘critical question’ (the leading one). Participants were asked to describe how fast the cars were travelling. ‘About how fast were the cars going when they hit each other? Contacted 

  The leading question biased their eyewitness recall of the event. The verb ‘smashed’ suggested a faster speed than contacted 
• EWT Misleading information - AO1 -Loftus experiment 2

  Short film of a crash, critical question either included verb ‘smashed’, ‘hit’ and a control (not asked about) the speed. Week later asked ‘Did you see any broken glass?’ there was no glass. Results- smashed condition twice as likely to report glass

  Verb smashed biased/affected their recall, suggesting increased speed and the question further distorted their original memory demonstrating the power of leading questions.
• EWT Misleading information - AO3

  +Standardised procedure- same clips shown

  -Mundane realism clips- less distressing 

  +/-Independent measures less chance of demand characteristics vs participant variables 

  +/-Use of questionnaire 

  -Students unfamiliarity with task/driving estimating speed 
• EWT Misleading information - AO1

  Post-event discussion: 

  when co-witnesses talk about the crime, they mix (mis)information from other witnesses with their own memories 

  Explanations why: memory contamination- when co-witnesses discuss a crime they combine (mis)information from other witnesses, with their own memory. memory conformity- for social approval of believing others are right or
• EWT Misleading information - AO1 -Gabbert


  60 students from the University of Aberdeen and 60 older adults recruited from a local community watched a video of a crime, a girl stealing money from a wallet. IMD- tested individually or pairs (co-witness group)

  71% recalled info they had not seen on questionnaire, testing their memory of the event. 60% said that the girl was guilty. Post-event discussion and the powerful effect this can have on the accuracy of eyewitness testimony.
• EWT Misleading information - AO3

  +Some population validity tested 2 different populations students and adults 

  -Mundane realism video clip. However, she did show them 2 different angles which would happen in real-life crimes

  - Pps knew they were taking part in research and were more likely to have paid close attention to the details of the video clip. 
• EWT Misleading information - AO3-Evaluation of misleading info overall

  Individual differences in the accuracy of EWT- Anastasi and Rhodes

  Older people were less accurate than younger people when giving eyewitness reports all age groups were more accurate when identifying people of their own age group (own-age bias)
• EWT Anxiety - Johnson & Scott (1976): negative effect - AO1


  Pps invited to take part in a study. IMD, overheard a heated argument and a man walked past either holding a greasy pen or a bloody knife. High anxiety condition led to less accurate recall. 33% correctly identified the man from 50 photos, compared to 49% in the low anxiety condition- weapon focus effect
• EWT Anxiety - Johnson & Scott (1976): negative effect - AO3

  +Lab studies high control, either saw greasy pen or bloody knife

  +/-Some ecological validity, artificial setting but within that it was staged as a real-life event.

  -Unethical- induced anxiety, deception 

  -Demand characteristics, knew they were waiting for research?

  -Extraneous variables-Surprise not anxiety?
• EWT Anxiety - Yuille and Cutshall (1986): positive effect - AO1


  Real-life crime, the owner of a gun shop was shot dead. 13/21 witnesses agreed to take part. After 5 months, those most anxious, their recall was most accurate. They could recall a higher number of details. 88% compared to 75% for the less-stressed group. Anxiety may enhance EWT- fight or flight increases awareness
• EWT Anxiety - Yuille and Cutshall (1986): positive effect - AO3

  +Higher ecological validity 

  -Unrepresentative, only 13 of 21 witnesses-  agreed to take part-perhaps these people would have produced different results.

  -CV- media reports could have influenced their memory, no way of controlling this 

  -Issues of self-reported stress, difficult to compare 
• EWT Anxiety - Yerkes-Dodson Law (1908) 


  suggests that the relationship between performance and arousal/stress is curvilinear and looks like and ‘inverted U’. 

  This means that performances increases with stress up to an optimal point where it starts to decrease drastically