memory

• Memory is defined as the process by which we retain information about events that have happened in the past.
• Coding: the way in which information is translated into a form which the memory store can understand
• Capacity: the amount of information which can be held in a memory store
• Duration: the length of time that information can be held in a memory store
• Sensory registers have an unlimited capcity but the duration is very brief unless attention is directed to that register.
• Sensory registers code through visual and acoustic stimuli, and are the first to be activated.
• STM has a capacity of 7 +/- 2 and a duration of approximately 18 seconds. It codes through acoustic stimuli.
• STM: Jacobs showed participants a series of items where more were added everytime the list was correctly recalled, which continued until only half the list was remembered. It was found that 7 +/- 2 chunks of information could be recalled however the size of the chunks was important.
• STM: Miller found that everyday items came in groups of 7. Furthermore, chunking into meaningful units allowed people to remember as many numbers as they could letters.
• STM and LTM: Baddeley asked participants to remember words acoustically similar or dissimilar and words semantically similar or dissimilar. They were then asked to recall them immediately or after a delay.
• STM: Baddeley findings:

  • Participants were more able to remember acoustically dissimilar words from STM
  • Words that sounded the same were harder to remember through maintenence rehearsal
• STM: Peterson and Peterson showed participants trigrams and asked them to either recall them or use the brown Peterson technique to prevent maintenance rehearsal
• STM: Peterson and Peterson findings:

  • The longer maintenance rehearsal was prevented, the fewer trigrams were remembered
  • 90% were remembered after 3 seconds, 5% were remembered after 18 seconds
• LTM has an unlimited capacity and a duration of a lifetime. It codes through semantic stimuli.
• Maintenance rehearsal: the repetition of information in its original, unaltered form
• LTM: Bahrick had 392 Americans aged 17-74 identify old class mates through name recognition or photo recognition.
• LTM: Bahrick's findings:

  • Participants who left up to 47 years ago could recall 80% through names and 70% through photos
• LTM: Baddeley findings:

  • Participants were more likely to remember semantically dissimilar words from the LTM
  • words with the same meanings are harder to remember using elaborative rehearsal
• Elaborative rehearsal: Maintains information in the LTM by connecting old information with new information
• Storage: keeping information in your memory until it is needed
• Retrieval: recovering information that has already been stored
• Encoding: taking information from the environment through the senses and changing it so it can be stored.
• Studies into coding, capacity and duration evaluations (+)

  • Bahrick's research has high external validity- When the findings can be generalised to real life. Real life memories were studied. Shepard (1967) when meaningless pictures were used, recall was lower. However, extraneous variables not controlled.
• Studies into coding, capacity and duration evaluations (-)

  • Peterson and Peterson and Baddeley's research have low ecological validity- When the findings cannot be generalised to real life. Both have artificial stimuli, not required to be remembered in everyday life. Findings have limited applications to real settings
• Studies into coding, capacity and duration evaluations (-)

  • Miller's research may not be reliable- Have not been replicated. Cowan (2001) reviewed other research into capacity of STM and found it to only be about 4 chunks. Suggests capacity is not as extensive as 7 items suggested by Miller. Lower end of Miller's estimation is more appropriate.
• Studies into coding, capacity and duration evaluations (-)

  • Peterson and Peterson's research lacks internal validity- Means the procedure doesn't measure what it intends. Participants asked to count backwards in threes from 100 to prevent maintenance rehearsal. Original information may have been lost through displacement rather than spontaneous decay.
• The Multi-store Model of Memory

  • Is an explanation for how information flows between memory stores
  • Believes in 3 permanent structures, each with their own capacity and duration; Sensory memory, Short term memory, Long term memory.
• Serial position effect- Murdock

  • Shows that there are separate ST and LT stores
  • Shows information is transferred to LTM through rehearsal
  • Shows STM has a limited capacity as words in the middle are displaced by recent ones.
• Primacy effect


  The superior recall of items at the beginning of a list, these are rehearsed and transferred to LTM
• Recency effect


  The superior recall of items at the end of a list, these are still held in the STM, however because of STM limited capacity they are only there until they are displaced by more recent words.
• The Multi-store Model of Memory Evaluation (+)

  • Convincing research evidence- Glanzer and Cunitz (1966), in a presentation that information at the start and end is remembered and all other information is forgotten. Suggests separate stores for STM and LTM.
• The Multi-store Model of Memory Evaluation (-)

  • Evidence suggests more than one type of STM- Shallice and Warrington (1970), After a motorbike accident, KF's STM for digits was poor when read aloud, but was better when read to himself. Suggests one store for auditory information and one for visual information, better to use WMM.
• The Multi-store Model of Memory Evaluations (+)

  • Convincing research evidence- Peterson and Peterson and Bahrick (1975). Peterson and Peterson found participants could recall trigrams for up to 18s. Bahrick found participants could recall classmates from up to 47 years ago. Suggests STM and LTM have different duration's and therefore must be separate unitary stores.
• The Multi-store Model of Memory Evaluations (-)

  • Only explains one type of rehearsal- Craik and Watkins (1973) argued 2 types of rehearsal; maintenance and elaborate. Maintenance rehearsal maintains information in STM but elaborate rehearsal is needed to transfer information to the LTM. MSM does not explain this.
• The Multi-store Model of Memory Evaluations (-)

  • Oversimplifies LTM- Evidence suggests LTM is not a unitary store. For example, we have different LTM stores for memories, facts, and actions. The MSM does not account for the different types, assuming there is one store therefore oversimplifies LTM.
• The Multi-store Model of Memory: Case studies

  • Supporting evidence through case studies of brain damaged patients
  • If a persons damage effects their STM, it shows there is a STM to damage in the first place.
  • Similarly, if there's damage to LTM but STM is intact, it shows the two stores are separate and different.
• The Multi-store Model of Memory: Clive Wearing

  • A professional musician who suffered amnesia after a viral infection
  • Episodic memories were damaged but procedural memories were still intact
  • Highlights a criticism: MSM states LTM is a unitary store, suggesting all LTM's are stored in the same way. Whereas, other psychologists have suggested there are different types of LTM each responsible for different memory types.
• Tulving: Episodic Memory

  • Memories for past events or experiences that have happened to us, which we have to consciously remember.
  • They are created by personally experiencing something
  • Usually associated with the times and places we did things and our emotions about the event (time-stamped)
  • They can be easily forgotten
• Tulving: Semantic Memory

  • Memories for learnt facts and information, which we have to consciously remember
  • They are created by having learnt information or general knowledge; memories of concepts and rules
  • We do not tend to recall the time and place we learnt them
  • They can be easily forgotten
• Tulving: Procedural Memory

  • Memories of how to perform skills and actions, which become unconscious over time.
  • They are created by repeating an activity multiple times; with muscle-based memory
  • We find it difficult to explain to someone else because we recall them without conscious awareness
  • They are resistant to being forgotten