Memory

• Research on capacity- Jacobs (1887)

  • Serial digit span study
  • Ppt presented with an increasingly long sequence of digits that they have to report back in order.
  • When they fail, on 50% of the trials ppt had reached their digit span capacity.
  • Jacobs found most people remembered 5-7. After this, the scores decreased
• evaluation on jacobs capacity

  • Recalling lists of letter lacks mundane realism and therefore ecological validity which suggests that it its not totally reliable
  • However other research confirms the results supporting the validity
• Span of memory and chunking- miller (1956)

  • conducted similar experiments ad argues that most things come in 7s. 7 notes on a musical scale, 7 days of the week etc
  • Concluded that on average we can recall 7 items with a range of between 5-9 items. Suggested that age may also influence STM capacity.
  • chunking is grouping information together to help improve memory capacity
• Evaluation of miller

  • Miller may have overestimated the capacity of STM. Cowan concluded capacity of STM was only about 4 chunks
  • Simon (1974) found that chunks may vary depending on type of ,material being recalled .
  • This suggests that Miller may not be 100% accurate and his results might not be too reliable
• Research on coding- baddeley 1966

  • Gave different lists of words to 4 groups of ppt to remember.
  • Group 1- acoustically similar, group 2- acoustically dissimilar, group 3- semantically similar, group 4- semantically dissimilar.
• Research on coding- Baddeley

  • Found when asked to recall word lists immediately (STM) acoustically similar words performed the worst recall, only 10% as they confused similar sounding words. Real of the other lists 60-80% which shows STM is acoustically and visually.
  • Found when asked to to a task which took 20mins before recalling (LTM) that acoustic similar words not significantly different but semantic was 55% for semantically similar, recall of others was 70-80% suggesting LTM encodes semantically
• Research on coding- Baddeley evaluation

  • Weakness is that it is artificial stimulus so its not meaning material so we have to be cautious about generalisation therefore it lacks ecological validity
  • Weakness is its a lab study so shows causality but might lack ecological validity as may not represent real life activities, however a lab study can be replicated to check results.
• Peterson and Peterson

  Duration of STM:

  • Aim- to see if rehearsal was necessary to hold information In the STM store
  • Procedure- Ppt given sets of 3 letters to remember but immediately asked to count back in 3s for 18 seconds which was done to prevent rehearsal. Ppt then asked to recall words in the same order
  • Findings- ppt forgot virtually all info after 18 seconds. concluded that can't hold info in the STM store unless we rehearse it.
• Evaluation of Peterson and Peterson

  • Strength-Research conducted in a controlled experimental setting and so can be easily replicated and research supports it.
  • Weakness- unrealistic as people in normal life do not perform such tasks
  • Weakness- not representative sample as they were all undergraduates this means the study lacks ecological validity.
  • However, phone numbers can be applied to real life.
• Supporting evidence for the cognitive interview:

  Gieselman et al

  • Compared cognitive interview with standard interview using 51 volunteer ppt
  • Ppt watched 2 films of violent crimes and 48hrs later interviewed by police using either standard or cognitive interview
  • The cognitive group remembered more correct statements
  • Results showed that there was a significant increase in number of correct answers.
• • The cognitive interview was devised by geiselman et al (1985)
  • Aim was to improve the retrieval of information by eye witnesses
  • It is designed to maximise the range of retrieval cues
• Cognitive interview steps:

  1. Report everything- every detail even if they seem irrelevant or trivial.
  2. Reinstate the context- Recall the scene, the weather and thoughts and feelings. Related to context dependent forgetting.
  3. Reverse the order- describe event in reverse order, this prevents expectations of how event must have happened rather than actual event
  4. Change perspective- Describe event as would have been seen from different viewpoints. Should prevent the effect of schemas on recall.
• The enhanced cognitive interview

  Fisher et al, 1987 added 4 other recommendations to the cognitive interview:

  1. Reduce eyewitness anxiety
  2. Minimise distractions
  3. Getting witness to speak slow
  4. Ask open ended questions
• Evaluation of cognitive interview pt 1

  • Time consuming- Police personnel have to have special training and its expensive
  • Some elements may be more valuable than others (Milne and Bull)- found each induvidial element more valuable. Each technique used alone produced more info. Using report everything combined with context reinstatement produced better recall than other conditions
• Evaluation of cognitive interview pt 2

  • Cognitive interview is effective (Kohnken)- Meta analysis of 53 studies found the average increase of 34% in correct info when using cognitive interview compared with standard techniques. However, most tests used volunteers in a lab which means it has low ecological validity.
  • Cognitive interview creates an increase in inaccurate info (Kohnken)- Research shows some inaccurate info may be recalled using cognitive interview. Kohnken found 81% increase of correct info but also 61% increase of incorrect info when compared to SPI.
• The working memory model -Phonological loop

  • Deals with acoustically encoded info and holds 2 seconds worth of info.
  • It is subdivided; the auditory control system and the phonological store.
  • Auditory control system = inner voice, holds words heard and silently repeats them like an inner voice
  • Phonological store= Inner ear, spoken words enter for 1-2 seconds before fading
• The working memory model- visuo-spatial sketchpad

  • The vss stores visual and/or spatial info when required for example, visual and or spatial info stored here. (inner eye)
  • Visual= what things look like
  • Spatial= relationship between things
  • It has a limited capacity of 3-4 objects roughly
• The working memory model- Episodic buffer

  • Baddeley added the EB in 2000. it is a temporary store for information integrating the WMM and LTM
  • 'General store'
  • Temporary capacity store; binds verbal, visual and spatial info
  • Limited capacity of 4
• The WMM- central executive

  • Directs attention to tasks- decides what working memory pays attention to
  • Responsibilites are to monitor, coordinate and combine the operation of the slave systems
  • Limited capacity- data arrives at senses but can't be held for long |
  • Reasoning and decision making
  • Coding not limited to one form
  • The harder the job the harder the central executive has to work to split between 2 slave systems
  • Practice makes it easier
• WMM - evaluation

  • Clinical evidence- Shallice and Warrington case patient of KF. Supports because he only had problems recalling sounds but was able to remember images and faces. supports because it proves that his phonological loop was damaged but not visuo-spatial sketchpad
  • However it isn't generalisable because its only about one singular case study
• WMM- evaluation

  • Dual task performance- studies from dual task performance (Baddeley) ppt were able to recall 6 digit strings and perform accurately on the reasoning task. the 2 tasks didn't interfere with each other because they used different STM components. This means that there are different components within the STM because performance not affected
• WMM- evaluation

  • Lack of clarity over the central executive. it is unclear how the central executive decides what to pay attention too. its also unclear how episodic buffers links to the LTM and so its a weakness as it can't explain certain aspects. This means WMM is not fully explained.