Memory

• Research on CODING

  Baddeley (1966)

  ppts were given 4 sets of words to recall in order

  • acoustically similar
  • acoustically different
  • semantically similar
  • semantically dissimilar
• Research on CODING

  Baddeley (1966)

  Findings -

  When asked to recall immediately they made significantly more mistakes on words that sounded alike

  Conclusion -

  STM info is coded acoustically, when we recall info from STM similar sounding words get confused
• Research on CODING

  Baddeley (1966)

  Findings -

  asked to recall after 20 mins the ppts were more likely to confuse semantically similar words

  Conclusion - LTM info is coded semantically, when recalling info from LTM similar meaning words get confused
• Research on CAPACITY

  Jacobs (1887)

  Measured digit span

  Read out digits/letter to ppts and increased the length of these digits by one each time until the ppt couldn't recall all digits in the correct order
• Research on CAPACITY

  Jacobs (1887)

  Findings - mean span for digits was 9.3 and for letters was 7.3

  Miller (1956)

  STM has a capacity of between 5 and 9 (7+/-2) chunks of info
• Research on DURATION of STM

  Peterson & Perterson (1959)

  presented ppts with trigrams

  ppts then asked to count backwards in 3s

  they were then asked to stop after varying periods of time e.g. 3,6,9,12,15 and 18 secs
• Research on DURATION of STM

  Peterson & Peterson (1959)

  Findings - after 3 seconds average recall was 80% and after 18 seconds it was about 3%

  Conclusion: duration of STM is about 18 - 30 seconds
• Research on DURATION of LTM

  Bahrick et al. (1975)

  used an oppurtunity sample of 392 american ex-highschoolers aged between 17 and 74

  • free recall of the names of their former classmates
  • a photo recognition test where they were aksed to identify their former classmates from 50 photos, only some of which were their classmates
  • a name recognition test
  • a name and photo matching test
• Research on DURATION of LTM

  Bahrick et al. (1975)

  Findings -

  Photo recognition - 90% within 15 year, 70% after 48 years

  free recall - 60% within 15 years, 30% after 48 years

  Conclusions - duration of LTM is up to a lifetime
• Multi-store model of memory - Evaluation

  Limitation -

  • evidence which suggests there is more than one stm store
  • case study of KF who had amnesia - his STM for digits that were read out loud to him was poor (acoustic) but when he read them for himself , his recall was much better (visual).
  • suggesting MSM is wrong in suggesting there is just one STM store
• Multistore Model - Evaluation

  Limitation -

  • prolonged rehearsal is not needed for transfer into LTM
  • researchers found that the type of rehearsal is more important than the amount and elaborative rehearsal is needed (linking info to existing knowledge
  • MSM does not full explain how information transfers to LTM
• Multistore model - evaluation

  strength -

  • support from studies showing LTM and STM are different
  • e.g. Baddeley (1966) and Peterson & Peterson (1956)
  • studies clearly show that LTM and STM are separate stores which supports the MSM

  Counterpoint -

  • studies use artificial material e.g. trigrams which have no meaning
  • in every day life we have to remember useful things like names, facts and places
  • MSM may not be a valid model of how memory works in every day life
• Types of LTM - Evaluation?

  strength -

  • evidence from HM
  • episodic memory severely impaired due to brain damage but semantic memory were unaffected as were procedural memories e.g could not recall stroking a dog half an hour ago but knew what a dog was and could still walk
  • supports different stores of LTM

  Counterpoint -

  • case studies lack control
  • no knowledge of the individuals memory before the damage
  • limits what clinical studies can tell us about different types of LTM
• types of LTM - evaluation?

  strength -

  • understanding LTM can help people with memory problems
  • as people age,they experience memory loss but only episodic
  • Belleville et al. (2006) created an intervention to improve episodic memory, after training they peformed better than a control group
  • shows distinguishing between types of LTM enables treatments to be developed
• Types of LTM - Evaluation?

  limitation -

  • conflicting research linking types of LTM to areas of the brain
  • some researchers found semantic memory is located on the left side of the prefrontal cortex and episodic on the right whereas other found episodic memories stored in left prefrontal cortex and right prefrontal cortex with episodic retrieval
  • challenges neuropsychological evidence to support types of memory
• Explanations for forgetting (interference) - evaluation?

  limitation -

  • only temporary and can be overcome using cues
  • ppts asked to recall different lists of words - recall for first list was 70% which got progressively worse with each list (PROACTIVE)when given cues to help recall rose again to 70%
  • only temporary forgetting which is a finding not predicted by interference theory
• explanations for forgetting (interference) - Evaluation?

  strength -

  • evidence of interference effects in everyday life
  • Baddeley & Hitch (1977) asked rugby players to recall the teams they had played against, results showed that recall did not depend on how recently they played but how many games they had played since then, players who played the most games (most interference) had the worst recall
  • interreference can explain real world situations of forgetting, increasing ecological validity of theory
• explanation for forgetting (interference) - evaluation?

  strength -

  • support from drug studies
  • gave ppts list of words and asked them to recall them, when words were learned under influence of drug diazepam recall was poor, but when list was learned before taking the drug recall was better, drug prevents new information from being learned
  • shows forgetting can be due to interreference - reducing the interference, reduces the forgetting
• explanation for forgetting (interference) - evaluation?

  Limitation -

  • evidence comes from lab studies
  • artificial task of learning and recalling a list of meaningless words
  • interreference may be more likely when learning meaningless material and may not be a reason for forgetting in real life situations
• explanation for forgetting (retreival failure) - evaluation?

  strength -

  • retrieval cues can help overcome forgetting in every day situations
  • walking into a room and forgetting why, the moment you go back to the first room you remember again. when having trouble remembering something try to recall the environment in which you learnt it first
  • shows strategies that we use in the real world help improve our recall
• explanation for forgetting (retrieval failure) - evaluation?

  strength -

  • research support for state dependent forgetting
  • Carter & Cassady (1998) gave antihistamine drugs to ppts. ppts had to learn and recall words.
  • Learn on drug - recall on drug
  • Learn on drug - recall not on drug
  • learn not on drug - recall on drug
  • learn not on drug - recall not on drug
  • in conditions where there was a mismatch between internal state performance was worse
  • supports encoding specificity principle
• explanation for forgetting (retrieval failure) - evaluation?

  Counter Point for state dependent forgetting -

  • context dependent forgetting affects not very strong
  • would be hard to find an environment as different as land from water in Baddeley & Godden research and learning in one room and recalling in another is unlikely to result in much forgetting
  • retrieval failure due to lack of contextual cues may not explain much everyday forgetting
• explanation for forgetting (retrieval failure) - evaluation?

  limitation -

  • context effects depend on the type of memory tested
  • Godden & Baddeley (1980) replicated underwater test with recognition instead of recall - when recognition was tested there was no context dependent effect and performance was the same in all 4 condition
  • retrieval failure is a limited explanation for forgetting
• effect of misleading info on EWT - evaluation?

  strength -

  • practical uses in the criminal justice system
  • police officers need to be careful about how they phrase their questions when interviewing eyewitnesses, psychologists are sometimes asked to explain limits of EWT to juries
  • psychologists can help improve the way the legal system works by protecting innocent people from unreliable EWT
• effect of misleading info on EWT - evaluation?

  limitation -

  • lack of ecological validity for Loftus & Palmer research
  • watching the video meant they saw events unfold from start to finish, whereas in real life the witnesses rarely see the whole event - either involved directly or see a small part of it
  • results do not reflect everyday car accidents and are unable to conclude if real life EW would be susceptible to leading questions in the same way
• effect of misleading info on EWT - evaluation?

  Limitation -

  • Loftus & Palmer study lacks population validity
  • only used American uni students, were less experienced drivers, who may be less accurate at estimating speeds
  • unable to generalise the results to other populations for example older, more experienced drivers who would not be as susceptible to leading questions
• effect if misleading info on EWT - evaluation?

  Limitation of memory conformity exaplanation-

  • post-event discussion actually does alter the memory of the event
  • showed ppts 2 clips, a muggers hair was dark brown in one and light brown in the other, ppts discusses clips in pairs, did not report what they had seen or the clips or what they heard from co-witness but a blend of both e.g. medium brown hair
  • memory itself is distorted through contamination from post-event discussion rather than memory conformity
• effects of anxiety on EWT - evaluation?

  limitation -

  • Johnson & Scott may not have tested anxiety
  • reason ppts focused on weapon was because they were surprised rather than scared, Pickel (1998) did an experiment with scissors, handgun, wallet and raw chicken. EWT accuracy was poorer in high unusallness condition (handgun and chicken)
  • lacks internal validity - therefore tells us nothing specifically about effect of anxiety on EWT
• effects of anxiety on EWT - evaluation?

  strength -

  • evidence supporting anxiety has a negative effect on recall
  • ppts asked to describe someone encountered in a horror labyrinth, using heart rate data they were split into high and low anxiety groups, 17% of high anxiety group correctly identified actor in line-up compared to 75% in low anxiety group
  • suggests high levels of anxiety does have a negative effect on immediate recall
• effects of anxiety on EWT - evaluation?

  strength -

  • evidence showing anxiety can have positive effects on recall
  • 58 witnesses to actual bank robberies were interviewed. found that recall was more than 75% accurate across all witnesses, direct victims were even more accurate
  • anxiety does not reduce the accuracy of EWT and may even enhance it
• effects of anxiety on EWT - evaluation?

  limitation -

  • Yerkes-Dodson law is too simplistic
  • only focuses on the physiological arousal involved in anxiety, however anxiety is more complicated and has more components that this theory ignores, such as they way we think about the stressful incident (cognitive)
  • the way we think about an event could have a different effect on EWT
• cognitive interview evaluation

  strength -

  • evidence that it works
  • meta analysis combined data from 55 studies comparing CI and ECI with standard police interviews, CI gave avergae of 44% inc in accurate info
  • shows that CI is an effective technique in helping witnesses to recall more accurate info

  counterpoint -

  • also found an inc in the amount of inaccurate info recalled by ppts, particularly in ECI which produced more incorrect details than the CI
  • CI may therefore sacrifice accuracy of EWT for number of details
  • meaning police officers such treat EW evidence from CIs and ECIs with caution
• cognitive interview evaluation:

  limitation -

  • not all elements are equally effective or useful
  • Milne & Bull (2002) found all 4 techniques were useful but a combination of report everything and reinstate the context produced better recall than any of the other elements
  • casts doubt on the credibility of the overall cognitive interview
• cognitive interview evaluation:

  limitation -

  • takes more time and training than standard police interview so may be reluctant to use it
  • many forces do not have the resources to provide this training for more than a few hours
  • complete CI is not a realistic method and might be better to just focus on a few key elements
• Research into CODING evaluation -

  strength -

  • identifies a clear difference between LTM and STM
  • important step in understanding the memory system which lead to the development of the multistore model
• research into CODING evaluation:

  limitation -

  • tasks are artificial/lack mundane realism/words held no personal meaning to ppts
  • when processing more meaningful info people may use semantic coding even for STM tasks which means the study has limited application
• research into CAPACITY: (Jacobs 1887)

  strength -

  • has been replicated with similar findings
  • suggests it is a valid test of digit span in STM
• research into CAPACITY evaluation: (Miller 1956)

  Limitation -

  • he may have overestimated STM capacity
  • Cowan (2001) reviewed other research and concluded that the capacity was only about 4 chunks
• Research on duration evaluation: (STM)

  limitation -

  • artificial stimulus
  • recalling different consonants does not reflect everyday memory activities where what we are trying to remember is meaningful
  • study lack external validity
• research on DURATION evaluation: (LTM)

  strength -

  • used meaningful materials
  • more realistic estimate for LTM
  • increases the internal validity