Memory

• Short-term memory

  • Coding = acoustic
  • Capacity = 7 +- 2
  • Duration = 18 secs
• Long-term memory

  • Coding = semantic
  • Capacity = unlimited
  • Duration = up to a lifetime
• Baddeley (1966)

  • Gave PPs a list of words then another list: either acoustically similar or semantically similar (controls were acoustically dissimilar and semantically dissimilar)
  • When asked to recall words immediately, acoustically similar words were more difficult to recall
  • when asked to recall words after 20 mins, semantically similar words were more difficult to recall.
• Miller (and) Jacobs


  Researched capacity of the STM. Both found that the capacity ranged from 5-9 pieces of information, and showed that this can be increased by chunking.
• Peterson & Peterson


  Researched the duration of the STM. PPs were asked to recall a trigram after a certain amount of time. They had to count back in threes from a number while they waited. They found that recall decreased as duration increased: at 3 secs= 80%, at 18 secs = 3%
• Bahrik et al

  • Researched the duration of the LTM.
  • Photo recognition: PPs given photos from high school yearbook and asked to recall classmates names. Recall decreased from 90% after 15 years to 70% after 48 years.
• HM case study

  • Brain surgery to relieve epilepsy - removed hippocampus
  • After surgery, couldn’t form new long-term memories but still had intact short-term memory.
  • Studied by Milner - procedural memory worked as areas of brain responsible (e.g. cerebellum) were still intact.
• Episodic memory


  Memories of time-stamped events about people and places retrieved consciously and with effort.
• Semantic memory


  Memories about our knowledge of the world including facts, words and concepts that are usually retrieved deliberately.
• Procedural memory


  Memories about our knowledge of learned skills such as riding a bike, requiring no conscious effort to retrieve.
• Clive Wearing case study

  • Suffered brain damage due to a virus
  • Episodic memory damaged but semantic and procedural memory still intact.
• Baddeley & Hitch


  Came up with the working memory model.
• Central executive


  Component of the WMM that controls attention into the subsystems of memory.
• Phonological loop


  Component of the WMM that processes acoustic information, holding heard words (phonological store) and using sub vocal repetition (articulatory processes).
• Visuo-spatial sketchpad


  Component of the WMM that processes visual and spatial information, consisting of the visual cache and inner scribe.
• Episodic buffer


  Component of the WMM that integrates information from the other subsystems into a single memory, using time sequencing. It links the working memory to the long-term memory.
• Interference


  When two pieces of information stored at different times conflict, resulting in forgetting.
• Proactive interference


  When an older memory interferes with a newer memory (cant remember new memory).
• Retroactive interference


  When a newer memory interferes with an older memory (can’t remember old memory).
• McGeoch & McDonald (1931)


  Studied the effects of similarity on interference. PPs learnt a list of words until they could recall it then learnt a second list: synonyms, antonyms, unrelated words, etc. They found that the more similar the words, the lower the recall.
• Baddeley et al. (1975)


  Studied dual-task performance. Gave PPs a visual and verbal task to complete simultaneously, performed well. However, when given either 2 visual or 2 verbal tasks to complete, performance decreased significantly. This is because both tasks are competing for the same subsystem.
• Shallice & Warrington KF case study 


  KF had poor short-term memory ability for auditory information but could process visual information normally. He also had better recall when he read things to himself than when they were read to him, suggesting his phonological loop was damaged but his visuo-spatial sketchpad was intact. This supports the existence of separate stores for short-term memory.
• Retrieval failure 


  Forgetting occurs because there are insufficient cues to help recall.
• Encoding specificity principle 


  For a cue to be helpful in recall, it has to be present at encoding and retrieval.
• Context-dependent forgetting 


  External cues are different at encoding and retrieval (e.g. different place).
• State-dependent forgetting


  Internal cues are different at encoding and retrieval (e.g. mood).
• Godden & Baddeley


  Studied contex-dependent forgetting. PPs learnt and recalled a list of words underwater or on land. They found that when the location was the same, average recall was 12.5, but when location was different it was 8.6.
• Carter & Cassady


  Studied state-dependent forgetting. PPs were given antihistamine drugs with a sedative effect, and learnt and recalled a list of words either on the drug or not. They found that recall was highest when the state of PPs was the same at learning and recall.
• Johnson & Scott


  Studied the negative affect of anxiety on recall. The study involved PPs seated in a waiting room hearing an argument, man walks out holding pen or paper knife covered in blood. They had to identify the man from photos - in Low anxiety condition 50% identified, in high anxiety condition 33% identified. Tunnel theory suggests attention narrows to focus on a weapon, so recall of other details is worse.
• Yuille & Cutshall


  Studied the positive affect of anxiety on recall. The study involved 13 witnesses from an armed robbery being interviewed 4 months after. They rated their stress at the incident - found that those reporting highest levels of stress had most accurate recall.
• Pickel (1998)


  Contradicting evidence for affects of anxiety on EWT. They conducted a similar study to Johnson & Scott with scissors, gun and chicken in a hairdresser. They found that accuracy was worse when more unusual item, suggesting weapon focus effect due to unusualness or surprise rather than anxiety.
• Loftus & Palmer


  Studied the effects of leading questions on EWT. This involved 45 American students watching a video of a car crash and being asked how fast the care was going when it _ the other car. When contacted was used speed said was 32 mph, but when smashed used speed was 40 mph. When asked if there was any broken glass, those who heard smashed were more likely to say yes.
• Response bias explanation


  When the wording of a question doesn’t impact our memory but influences how we choose to answer the question (E.g. smashed encourages a higher speed estimate).
• Substitution explanation


  Wording of a question causes our memory to be substituted (E.g. asking if there was broken glass causes us to rethink).
• Cognitive interview characteristics

  1. Reinstate the context
  2. Reverse the order
  3. Change perspective
  4. Report everything
• Enhanced cognitive interview 


  Fisher et al developed additional elements to focus on the social dynamics of the interview, including eye contact and how to minimise distractions.
• Kohnken et al


  Supporting evidence for the cognitive interview. They conducted a meta-analysis of studies comparing the cognitive interview to a standard police interview and found a 41% increase in accurate information when using the cognitive interview, suggesting it is effective.