Memory

• memory

  the psychological process of aquiring, storing, retaining and later retrieving information
• What are the 3 processes that memory is made up of?

  encoding, storage, retrieval
• Types of Memory: Sensory

  • Remembers sensory information after stimulus has ended eg. remembering a sound you heard in passing
  • Memory type with the shortest duration of 0.5 seconds
  • When a sensory experience is repeated and other memories are attached to it, it moves into short-term or long-term memory
  • High capacity
• Types of Memory: Short-Term/Active/Primary

  • Remembers specific information for a short time period, usually 15-30 seconds
  • Average person can store 7 +- 2 pieces of new information in their short-term memory
  • Lasts longer than sensory but shorter than long-term memory
  • Information can be kept in short-term memory through rehearsal of information; this usually doesn't work for longer than 10 minutes
  • Favours acoustic and visual coding
• Types of Memory: Long-Term

  • Stores majority of memories
  • Classed as anything we can remember after 30 seconds
  • Has unlimited capacity and a duration of at least 1 lifetime (47 years)
  • Split into explicit (conscious and deliberate memories) and implicit (unconscious memories)
  • 2 types of explicit memory: episodic (special events eg. first day of school) and semantic (random facts absorbed over time)
  • Implicit memories are often obtained when learning motor skills eg. riding bikes
  • Favours semantic coding
• Types of Memory: Working

  • Involves immediate, small amount of information used when cognitive tasks are performed
  • Can fall under category of short-term memory; the two are often used interchangeably
• Josepf Jacobs (1887)

  • Used 'digit test' to investigate capacity of short-term memory, where participants were given a list of numbers that they had to recite. The list would grow in size and Jacobs would stop asking once it was no longer recalled correctly.
  • Concluded that the capacity of short-term memory for digits is 9.3 and for letters is 7.3
• George Miller (1956):

  • Investigated the capacity of short-term memory
  • Saw how many things appeared in 7s eg. 7 days of the week
  • Theorized 'magical number' of 7 +- 2 pieces of new information that one could absorb at once
  • Found that people could remember 5 words as easily as they could 5 letters or 5 numbers
  • Developed idea of 'chunking', a memory technique involving grouping sets of information into meaningful 'chunks' to make them easier to remember
• angiography

  a type of X-ray studying the function of blood vessels
• coding

  the way and form in which the information is processed for storage
• capacity

  how much information can be stored
• duration

  how long information can be stored for
• Baddeley (1966) Aim: to assess whether coding in short term memory and long term memory is mainly acoustic (by sound) or semantic (by memory)

  
  

  Procedures:

  • 75 participants were presented with 1 of 4 word lists:

  1. acoustically similar
  2. acoustically dissimilar
  3. semantically similar
  4. semantically dissimilar

  • To test coding in short term memory, participants were given a list containing their original words in the wrong order and told to order them correctly
  • This was repeated for long term memory but with a 20 minute interval in between in which participants were given an interference task to prevent rehearsal
• Prof. Alan Baddeley (1966) Findings:

  Short Term Memory:

  • Participants did the worst with acoustically similar words - recalled 10%
  • Recall for the other lists was better and more similar - between 60% and 80%

  Long Term Memory:

  • Participants did the worst with semantically similar words - recalled 55%

  Conclusions:

  • Short term memory is coded acoustically as participants struggled to remember words that sounded too similar
  • Long term memory is coded semantically as participants struggled to remember words with meanings that were too similar
• How do advertisers use coding to help us remember adverts?

  Acoustic coding:

  • Alliteration
  • Association
  • Jingles
  • Patterns of repetition

  Semantic coding:

  • Use of meaning - content of the message is immediately meaningful to the viewer and they are motivated to remember it

  Visual coding:

  • Colour
  • Iconic images eg. celebrities
  • Symbols
• Baddeley (1966) Evaluation:

  (+) Identified a clear difference between long term and short term memory; led to multi-store model

  (+) High face validity - if we want to remember a shopping list we may recite it aloud (acoustic); if we want to remember a book we may try to recall the plot (semantic)

  (+) Shows cause & effect

  (+) Standardised: can be repeated to show reliability

  (-) Artificial tasks - no personal meaning, don't resemble the kinds of memory tasks people face in everyday life - low application & ecological validity
• Capacity Research Evaluation (Jacobs, Miller)

  (+) High validity: Jacobs' research has been replicated by better controlled studies

  (+) Miller's research discovered chunking, which further developed our understanding of short term memory

  (-) Jacobs' research is an old study (1887) so may have lacked controls eg. not taking account of confounding variables such as participants getting distracted

  (-) Low reliability: Miller may have overestimated short term memory capacity - Cowan (2001) reviewed similar research & concluded that short term memory capacity is 4 +- 1 chunks/items, suggesting that the lower end of Miller's estimate (5 items) is more accurate
• Paying attention to information causes it to enter our short term memory; in order for it to stay there it needs to be rehearsed
• Without rehearsal, short term memory lasts about 20 seconds
• Peterson and Peterson (1959):

  • Aim: Investigating the duration of short term memory
  • Procedure: 24 students in 8 trials memorised 3 consonants and were given a 3 digit number to count backwards from to prevent mental rehearsal. On each trial they stopped after varying periods of time: from 3 to 18 seconds (+3 each time)
  • Findings: after 3 seconds recall was 80%; after 18 seconds recall was 3%
• Bahrick et al. (1975):

  • Aim: Investigating the duration of long term memory
  • Procedure: 392 participants aged 17-74 were shown a set of photos and a list of names, some of which were ex schoolmates. They were asked to identify who were their ex schoolmates.
  • Findings: Those who left school in the last 15 years identified 90% of faces and names; those who left 48 years ago identified 80% of names and 70% of faces. Free recall was less accurate than cued recognition: free recall was 60% after 15 years & 30% after 48 years
  • Conclusions: Memory for faces and names is long lasting
• Evaluation of Duration Research:

  • (+) Bahrick et al's study had high ecological validity - they researched meaningful memories from real life (other studies using meaningless pictures resulted in lower recall rates), suggesting that their findings reflected a more real estimate of the duration of long term memory
  • (-) Peterson and Peterson's study had low ecological validity - they used meaningless stimuli in the form of artificial consonant syllables that didn't mean anything to the participants and do not represent everyday memory
• Multi Store Model:

  A) Atkinson and Shiffrin

  B) 1968

  C) Stimuli

  D) Sensory Memory

  E) Forgotten

  F) Attention

  G) Short term memory

  H) Acoustic and Visual Coding

  I) Forgotten

  J) Maintenance and Elaborative

  K) Rehearsal

  L) Encode

  M) Long term memory

  N) Semantic Coding

  O) Retrieve

  
• Types of Sensory Stimuli:

  • Touch: Haptic
  • Hearing: Echoic
  • Sight: Iconic
  • Smell: Olfactory
  • Taste: Gustatory
• Long term memories are not passive: they change and merge over time - this is why memory is not completely accurate.
• Shaping and storing long term memory is spread throughout the brain.
• Clive Wearing:

  • Has a severe form of amnesia that damaged his hippocampus, stopping him from remembering anything about his past or imagining his future
  • Writes that he is 'coming to life' in his diary as he can't remember writing in it before
  • He recognises his wife and still loves her; he also recognises his own handwriting but has no memory of writing things
  • He used to be a musician and conductor and can still play music perfectly; he can also still speak perfectly
  • When he sees his wife he greets her as if he hasn't seen her in years, even if she was last in the room a few minutes ago
• Henry Molaison (Patient HM):

  • Suffered from seizures due to childhood accident; had his hippocampus removed from both sides of his brain in surgery to ease them
  • This resulted in him losing his ability to form new long term memories
  • When assessed in 1955 aged 31, he believed that it was 1953 and he was 27 (the age at which he had the surgery)
  • However, he performed well on tests of immediate memory span, showing that his short term memory was still intact
• Multi Store Memory Model: Evaluation

  (+) Research support eg. Baddeley (1966)

  (+) Clinical evidence eg. Clive Wearing, HM, KF

  (+) First model of memory which led to a greater understanding of how memory works

  (-) Artificial tasks used to support MSM that don't represent real life memory

  (-) Oversimplified: more than one short term and long term memory store

  (-) Suggests that prolonged rehearsal is needed to transfer information into the long term memory, but Craik and Watkins (1973) found that the type of rehearsal, namely elaborative rehearsal, is more important
• Shallice and Warrington (1970):

  • Studied client 'KF' who had amnesia
  • KF's short term memory was very poor for digits when they were read aloud to him (acoustic processing), but improved when he read the digits to himself (visual processing)
  • This indicates that there are several stores within short term memory
• elaborative rehearsal

  linking new information to existing knowledge or thinking deeply about the implications of the existing knowledge - needed for long term memory storage and can transfer information to long term memory without prolonged rehearsal
• Explicit vs. Implicit Memories:

  Explicit:

  • Declarative
  • Only recalled in conscious mind
  • Includes episodic and semantic memories

  Implicit:

  • Non-declarative
  • Do not need to be recalled in the conscious mind
• Episodic:

  • Tulving, 1972
  • Autobiographical record of personal experiences
  • High processing of information leads to stronger memories
  • Prefrontal cortex associated with initial coding of episodic memories
• Semantic:

  • Contains all the knowledge learnt over a time period
  • Maintained over time: episodic memory gradually moves to semantic memory as the knowledge is remembered but the event in which we learnt it isn't
  • Associated with hippocampus; semantic coding is also associated with the front and temporal lobes
• Procedural:

  • How to do things eg. using language, motor skills
  • Allows us to perform learned tasks without conscious thought
  • Many of these skills occur in early life eg. getting dressed, walking
  • Involvement in language includes using correct grammar without thinking
  • Involves neocortex area (consists of primary motor cortex, cerebellum and prefrontal cortex)
• Long Term Memory Research: Strengths

  • Clinical evidence eg. Clive Wearing and HM where episodic memory was severely affected but semantic and procedural less so supports Tulving's idea of multiple types of long term memory
  • Studying people with brain injuries helps researchers to understand how memory works normally
  • Real world application to helping people with memory problems such as age related memory loss explored by Belleville et al. (2006)
• Belleville et al. (2006):

  • Produced intervention involving cognitive and virtual reality workouts and stimulating artistic and recreational activities to improve episodic memory in older people
  • The trained participants performed better on a test of episodic memory than the control group

  Older people struggle more with recalling recent personal events although past episodic memories remain intact.
• Long Term Memory Research: Weaknesses

  • Unique case studies (eg. Clive Wearing, HM, KF) can't be generalised
  • Lack of control over variables in clinical studies as brain injuries are unique and researchers have no knowledge of how the patient's brain worked before
  • Conflicting neuroimaging evidence despite precise brain scanning: Buckner and Petersen (1996) concluded that semantic memory is located on the left side of the prefrontal cortex and episodic on the right - Tulving et al. (1994) thought the opposite
• Procedural memory usually takes longer to form than explicit memory, potentially because it involves motor and spacial abilities.
• Why did Baddeley and Hitch criticise the multi store model?

  • They believed that the short term memory store was too simplistic and that short term memory is not just one single store.
  • Short term memory is seen as an active store holding information that is being worked on.
  • They argued that short term memory has different stores for acoustic and visual information.
  • This meant that tasks involving dual performance in one area (eg. 2 tasks involving acoustic) are unable to be done effectively but tasks involving dual performance with separate stores can be done together.