TYPES OF MEMORY

TYPES OF MEMORY

1. SHORT TERM MEMORY

   • CAPACITY
     • STUDY 1: JACOBS (1887)
       • PROCEDURE
         • Digit Span
         • Researchers read four digits + increased until the ppt couldn't recall the order correctly
       • FINDINGS + CONCLUSIONS
         • Average = ppts could repeat back 9.3 numbers + 7.3 letters in the correct order immediately after they were presented
       • CONDUCTED A LONG TIME AGO
         • Lacked adequate control of extraneous variables
         • EXAMPLE: some ppts may have been distracted while they were being tested so didn't perform as well as they might
         • Confounding variables present as they weren't controlled
           • BUT other results have confirmed Jacobs' findings, supporting the valisity
     • STUDY 2: MILLER (1956)
       • PROCEDURE
         • Made observations of everyday practice
         • Noted how things came in 7s (musical scale, days of the week, deadly sins...)
       • FINDINGS + CONCLUSIONS
         • Span of STM = 7 items +/- 2
         • Can be improved by CHUNKING (grouping sets of digits/letters into meaningful units)
       • OVERESTIMATED CAPACITY
         • COWAN (2001) reviewed other research
           • Concluded that the capacity of STM = about 4 chunks
         • Suggests Miller's lower end of 5 items is more accurate
   • DURATION
     • STUDY 1: PETERSON + PETERSON (1959)
       • PROCEDURE
         • 24 students were given a consonant syllable to remember + a 3 digit number to count backwards for either 3, 6, 9, 12, 15 or 18 seconds
       • FINDINGS + CONCLUSIONS
         • Recalled about 80% of the syllables correctly with a 3 second interval
         • Average recall after 18 seconds = about 3%
         • Duration of STM w/out rehearsal = about 18-30 seconds
       • ARTIFICIAL STIMULUS
         • Lacked external validity as memorising syllables doesn't reflect what you remember in real life
         • But sometimes we do remember meaningless information such as phone numbers, so the study isn't totally irrelevant
   • CODING
     • STUDY 1: BADDELEY (1966)
       • PROCEDURE
         • Acoustically similar + dissimilar words
         • Semantically similar + dissimilar words
       • FINDINGS + CONCLUSIONS
         • Immediate recall = worse with acoustically similar words
           • STM = acoustic
         • Recall after 20 mins = worse with semantically dissimilar words
           • LTM = semantic
       • DIDN'T USE MEANINGFUL MATERIAL
         • When processing meaningful info, people may use semantic coding even for STM tasks
         • Results therefore have a limited application
         • Should be cautious when generalising the findings to different kinds of memory task

2. LONG TERM MEMORY

   • DURATION
     • STUDY 1: BAHRICK ET AL (1975)
       • PROCEDURE
         • Ppts = 392 Americans aged between 17-74
         • RECOGNITION TEST: 50 photos from ppt's high school yearbook
         • FREE RECALL TEST: ppts listed names of their graduating class
       • FINDINGS + CONCLUSIONS
         • Tested 48 years after graduation, recall was 70% accurate in photo recognition
         • Free recall was less accurate
       • HIGH EXTERNAL VALIDITY
         • Real life, meaningful memories were studied
         • However, confounding variables are not controlled as ppts may have rehearsed over the years by looking back at the photos
   • CODING
   • EPISODIC MEMORY
     • STORES EVENTS FROM OUR LIVES
       • Likened to a diary of daily happenings
       • EXAMPLE: your most recent visit to the dentist, the psychology class you had yesterday, the breakfast you ate this morning
     • EPISODIC MEMORIES ARE COMPLEX
       • Time-stamped - you remember when they happened
       • Involve several elements (people, places, objects are behaviours)
       • Conscious effort to recall them
     • CASE STUDY SUPPORT
   • SEMANTIC MEMORY
     • STORES OUR KNOWLEDGE OF THE WORLD
       • Combination of an encyclopedia + a dictionary
       • EXAMPLE: includes knowledge of such things as applying to university, the taste of an orange + meaning of words
     • NOT TIME STAMPED
       • Less personal + more about the knowledge that we all share
       • EXAMPLE: we don't usually remember when we first learned about 'Justin Bieber'
   • PROCEDURAL MEMORY
     • STORES MEMORIES FOR ACTIONS + SKILLS
       • Memories of how we do things
       • EXAMPLE: driving a car, playing table tennis
     • RECALL OCCURS WITHOUT AWARENESS OR EFFORT
       • Quite hard to explain to other people because we recall without a conscious effort
       • EXAMPLE: explaining how to ride a bike, trying to tell someone how to change gear when driving