Psychology - Memory

Psychology - Memory

1. The Nature of Memory

   • Duration
     • A measure of how long a memory lasts before it is no longer avaliable
     • Key Study on STM - Peterson and Peterson
       • Experimenter said a consonant syllable followed by a three-digit number (e.g. WRT 605
         • Ps asked to count back in 3s/4s from number then asked to recall the syllable after a certain amount of time
           • Ps remembered 90% at 3 sec interval and 2% at an 18 sec interval
     • Key Study on LTM
       • Ps asked to put names to faces in their high school year book
         • 48 years on, Ps were 70% accurate
     • Evaluation
       • Other research has suggested that when Ps do not expect to be tested after the interval, forgetting may occur after just 2 seconds - not a full understanding of STM
       • Narine et al found items could be recalled after up to 96 seconds when asked to recall same items across trials - info remains in STM unless new material replaces it
   • Capacity
     • A measure of how much can be held in memory
     • Key study on STM - Jacobs
       • Line of numbers, Ps to look at digits, cover them then recall, going along the line (1 number covered then 2 then so forth)
         • Average span found to be 9.3 items when it was digits, found to be 7.3 with letters
     • Increasing STM capacity
       • Magic number - 7 plus/minus 2
       • People remember more using chunking - can recall 5 words as well as 5 letters as we chunk things together
     • Evaluation
       • Individual differences - 8 year olds could remember 6.6 digits whereas 19 year olds could remember 8.6
       • Real world application - postcodes and number plates easily remembered by chunking
       • STM may be more limited - found to be only 4 chunks
   • Encoding
     • The way information is changed so it can be stored in the memory
       • LTM codes semantically
       • STM codes acoustically
     • Key Study on Encoding - Baddeley
       • Ps given list of acoustically similar/dissimilar words and semantically similar/dissimilar words
         • Ps had difficulty remembering acoustically similar words in STM and semantically similar words in LTM
     • Evaluation
       • STM also uses visual encoding - Ps encode visually in STM if given a visual task and prevented from doing verbal rehearsal
       • LTM is not exclusively encoded semantically

2. Multi-store model (MSM)

   • Sensory Memory
     • Composed of several stores - the eyes, ears, nose, etc.
       • Constantly receiving information, remains in store for very brief period
         • Information transferred to STM if person pays attention
     • EVIDENCE
       • Information decays rapidly in sensory store
         • Ps saw grid of digits and letters for 50 milliseconds and asked to write down all 12 items or just a row
           • Recall was poorer when asked to write down whole thing (42%) than one row (75%)
   • Short Term Memory
     • Information disappears quickly if it is not rehearsed
       • Information will also disappear if it is displaced because STM has a limited capacity
   • Long Term Memory
     • Information moves from STM to LTM by rehearsal
   • EVIDENCE for 3 separate memory stores
     • The serial position effect
       • Ps given list of 20 words and asked to recall any of them
         • Ps tended to remember words at the start of the list (primary) and the end (recency)
           • Primary effect occurs as they're best rehearsed so transferred to LTM and recency effect occurs because end words are in STM
     • Case Studies
       • HM - hippocampus removed, could no longer form long-term memories
     • Areas of brain associated
       • PET scans and fMRI can take images of the brain to see which parts are active when doing particular tasks
         • Prefrontal cortex activated during STM engagement, hippocampus is activated during LTM engagement

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