Memory: Key Studies


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  • Memory: Key Studies
    • Coding, capacity and duration
      • Baddeley (1966) - research on coding
        • gave different lists of words to four groups of people to remember.
          • acoustically (sound) similar, acoustically dissimilar, semantically (meanings) similar and semantically dissimilar.
          • when asked to recall immediately (STM) they did worse with acoustically similar words
          • when asked to recall after 20min (LTM) they did worse with semantically similar words
            • this suggests that information is coded semantically is LTM
              • artificial stimuli was used - cautious about generalising
      • Jacobs (1887) - research on capacity
        • developed a technique to measure digit span
          • 4 digits then pps. had to recall these in correct order and he would increase no.
            • digits = 9.3 items.    letters = 7.3 items.
              • lacked validity - conducted a long time ago
        • Miller (1956) made an observation that things come in 7, Span or capacity of STM is 7. Created chunking.
          • may have over-estimated capacity of STM
      • Peterson and Peterson (1959) - research on duration (STM)
        • tested 24 un-dergraduate students. Each student took part in 8 trials.
          • on each trial, a student was given a consonant syllable (trigram, such as YCG)
            • also given a 3-digit number to remember and count back from (to prevent mental rehearsal)
              • retention interval from 3 seconds to 18. = STM has short duration unless was repeated.
        • Bahrick et al (1975) - research on duration (LTM)
          • Studied 392 pps aged 17 and 74.
            • school year books were obtained and recall was tested in various ways
              • 1) photo-regcognition (pr) consisting of 50 photos. 2) free recall (fr), pps. had  to recall names
                • Pps within 15 years of graduating were 90% accurate (pr). after 48 years, accuracy dropped to 70% (pr).
                  • after 15 years 60% (fr) and after 48 years 30% (fr) = LTM duration can last a long time.
                    • high external validity - real time meaningful memories were studied.
                      • confounding variables are not controlled - his pps may have looked over photos since graduation.
        • meaningless stimuli - lacked external validity
    • Forgetting
      • Interference - effects of similarity - McGeoch and McDonald (1931)
        • studied retroactive interference by changing the amount of similarity between two sets of materials.
        • pps. had to learn a list of words 100% accurately and then were given a new list to learn, 6 groups:
          • Group 1: Synonyms Group 2: Antonyms Group 3: word unrelated to original ones Group 4: nonsense syllables Group 5: 3-digit numbers Group 6:no new list.
            • most similar material (synonyms) = worse recall. This shows that interference is strongest when memories are similar.
              • lab study = increases validity
                • artificial materials
      • Retrieval Failure - Context-dependant forgetting - Godden and Baddeley (1975)
        • interesting study of sea divers working uderwater.
          • 4 conditions to learning a list of words
            • learn on land - recall on land
            • learn on land - recall in water
            • learn underwater - recall underwater
            • learn underwater - recall on land
          • when cues are absent hen there is more forgettng. recall was worse in mismatched conditions.
            • real life applications
    • Factors affecting eyewitness testimony
      • Post-event discussion - Gabbert (2003)
        • studied pps. in pairs, each pps. watched a video of the same crime scene filmed from different angles. both pps. then discussed what they saw.
          • 71% of pps. mistakenly recalled aspects of the event that they did not see in the video not picked up in the dicussion.
            • Gabbert concluded that witnesses might often go along with others to win social support or bc they believe that the other person is right = memory conformity
      • Leading Questions - Loftus and Palmer (1974)
        • arranged pps. to watch clips of car accidents and then asked questons.
          • critical (leading) question 'about how fast were the cars travelling when they hit each other' - hit was the leading verb
            • 5 different conditions: hit, contacted, bumped, collided, smashed
              • mean estimated seed was calculated for each condition: contacted = 31.8mph, smashed = 40.5mph.
                • real-life applications, changed legal system
                  • pps. watched clips, they didn't experience the crashes - artifical task
            • critical verb altered memory of accident
              • mean estimated seed was calculated for each condition: contacted = 31.8mph, smashed = 40.5mph.
                • real-life applications, changed legal system
                  • pps. watched clips, they didn't experience the crashes - artifical task
      • Anxiety - Johnson and Scott (1976)
        • led pps. to believe they were in a lab study, in waiting room pps. 'over heard' an argument and were exposed to either of two conditions
          • A. 'low-anxiey' - pps. over heard argument and a man walked out with a pen and grease on his hands
            • B. 'high-anxiety'  pps. overheard same argument + broken glass sounds and then a man walked out with a bloody paper knife
              • the pps. had to pick out the mans face out of 50 photos. A = 49%        B = 33%          - tunnel theory, witness attention narrows to focus on weapon (source of anxiety)
          • B. 'high-anxiety'  pps. overheard same argument + broken glass sounds and then a man walked out with a bloody paper knife
            • the pps. had to pick out the mans face out of 50 photos. A = 49%        B = 33%          - tunnel theory, witness attention narrows to focus on weapon (source of anxiety)
        • Positive effect on recall - Yuille and Cutshall (1986)
          • interviews of real life victims of a shop shooting, 13/21 agreed to study. 4-5 months after the shooting happened.
            • accuracy w determined by no. of details once repots. witnesses also asked to rate stress level at the time using a 7-point scale.
              • those that experienced higher levels of stress were more accurate (88% compared with 75% of less stressed group)

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