Memory

• Limitation of Peterson and Peterson and Baddeley's research


  • Low ecological validity
  • Findings cannot be generalised to real life settings
• Peterson and Peterson and Baddeley's research used artificial stimuli rather than meaningful information, unlike information we are required to remember in everyday life
• Limitation of research into the capacity of STM


  • Miller's findings have not been replicated, suggesting the findings may not be reliable
  • Cowan (2001) concluded the capacity of STM was only about 4 chunks, suggesting the capacity is not as extensive as the 7 items suggested by Miller
• The lower end of Miller's estimation is more appropriate; five items rather than seven
• Strength of Bahrick's research into the duration of LTM


  • Higher external validity
  • Real life memories were studied, as it required recall of classmates
• Shepard (1967) found that when studies into LTM were conducted using meaningless pictures, recall rates were lower
• Confounding variables were not controlled; for example, by chance, Bahrick may have selected participants who regularly looked at yearbook photos or kept in contact with school friends, thereby rehearsing their memories over the years
• Limitation of Peterson and Peterson's research

  • Lacks internal validity
  • Participants were asked to count backwards in threes from 100 to prevent maintenance rehearsal, so the original information may have been lost through displacement rather than spontaneous decay
• Strength of the Multi-Store Model (MSM)


  • Convincing evidence to support it from Peterson and Peterson (1959) and Bahrick (1975), who found STM and LTM have different durations
• This suggests that, as STM and LTM have different durations, each store must be separate and unitary as the model predicts
• Further strength of the MSM

  • Convincing evidence to support it from Glanzer and Cunitz (1966), who found the primacy and recency effects suggesting separate and unitary stores for STM and LTM
• Limitation of the MSM

  • Evidence to suggest we have more than one type of STM, from Shallice and Warrington (1970) who found KF's STM for digits was poor when they read aloud to him, but better when he read the digits himself
• This suggests there may be one short-term store to process visual information and another to process auditory information, so the MSM may not fully explain memory
• Second limitation of the MSM

  • It only explains one type of rehearsal, but Craik and Watkins (1973) argued there are two types - maintenance and elaborative
• This suggests the MSM is limited, as it does not explain elaborative rehearsal
• Further limitation of the MSM

  • It oversimplifies long-term memory, as there is multiple evidence to suggest LTM is not a unitary store
• This suggests the MSM is limited, as it does not account for these different types of long-term memory
• Episodic memories


  Memories for past events or experiences that have happened to us, which we have to consciously remember. Associated with times and places.
• Semantic memories


  Memories for learnt facts and information, which we always have to consciously remember
• Procedural memories


  Memories of how to perform skills and actions, which become unconscious over time
• Strength of explanations for separate types of long term memories


  • Convincing research to support them from studies of different parts of the brain
  • Tulving (1994) found episodic and semantic memories were associated with different parts of the prefrontal cortex
• Further strength of explanations for separate types of long term memories

  • Convincing research to support them from the case studies of HM and Clive Wearing, who struggled to recall events but had unaffected semantic memories
• However, due to the nature of case studies and the lack of control of variables, it can be difficult to generalise and understand exactly how LTM works
• Final strength of explanations for separate types of long term memories

  • They have led to practical applications, such as Belleville et al (2006) finding that episodic memories could be improved in older people with mild cognitive impairment
• Limitation of explanations for separate types of long term memories

  • There may only be two types of LTM, not three, as Cohen and Squire (1980) argued episodic and semantic memories were both stored together in one declarative memory store
• Strength of the Working Memory Model (WMM)

  • Convincing research to support it from Logie's dual task study (1986), which found performance was good when tasks used different systems but poor when they used the same system
• This suggests STM is made up of different stores, which can perform different tasks at the same time; something which the multi-store model cannot explain
• Further strength of the WMM

  • Convincing research to support it from Shallice and Warrington's (1974) case study of KF, who had worse memory for auditory than visual information
• This suggests there are two separate stores for visual and auditory information, which are independent of each other
• Further strength of the WMM

  • Convincing research to support the existence of the central executive from Braver et al. (1997), who found increased prefrontal cortex activity as the central executive's demands increased
• Limitation of the WMM

  • Lack of clarity over the central executive, which Baddeley (2003) agreed was the least understood component of the model and needs to be more clearly defined
• Interference


  Forgetting occurs because one memory interferes or blocks another
• Interference is worse when the memories are similar
• Proactive interference


  Older memories interfere with an attempt to remember newer memories
• Retroactive interference


  Newer memories interfere with an attempt to remember older memories
• Strength of interference as an explanation for forgetting


  • A lot of research evidence supports the theory, such as from McGeoch and McDonald (1931) and Schmidt (2000)
• As the findings come from laboratory studies with high control over variables, we can be confident that interference is a valid explanation for forgetting
• Further strength of interference as an explanation for forgetting

  • Real life studies support the theory, such as Baddeley and Hitch (1977) finding accurate recall depended on the number of games played, not how long ago
• Limitation of interference as an explanation for forgetting

  • Research that supports the theory uses short time periods, which is not reflective of how we learn and remember most information in real life
• Therefore we may not be able to generalise the findings from research outside a laboratory setting; the role of interference may be exaggerated