Memory Research

Memory Research

1. Capacity

   • Jacobs (1887)
     • procedures
       • lab Experiment
       • digit span technique - numbers increasing by 1 after each set is recalled. e.g. 1234
       • digit span - e.g. 3472 (next line) 01847
       • presentation time = 1/2 a second between each digit
       • trial ended when ppt recalled the digit span incorrectly
     • Findings - average recall between 5 and 9
     • Conclusion
       • STM has a limited storage capacity.
       • not determined by the nature of the info, but the size of the STM span
     • Strengths
       • led to further research - miller- chunking
       • applied to real life - post code/phone numbers
     • weaknesses
       • lab experiment/ un meaningful task. lacks mundane realism.

2. Encoding

   • Baddeley (1966)
     • procedures
       • independent measures design
       • one group: recall words immediately 2nd group: 20 min delay
       • 2 pairs of lists - 1= similar/not sounding words (cat, mat). 2=similar/not meaning words (big, large)
     • findings
       • STM - similar sounding was best
       • LTM - similar meaning was best
     • strengths
       • shows that STM and LTM encode different ways and shows that they are separate stores.
     • weakness
       • lab experiment - lack mundane realism
     • conclusion
       • the importance of sound was shown in STM. and the importance of meaning was shown in LTM
       • there was less confusion when the word lists had distinct sounds and meanings.
       • has implications of improving memory

3. duration

   • LTM
     • Bahrick (1975)
       • procedures
         • opportunity sample
         • 392 ex-pupils
         • aged 17-74
         • two tasks: 1=recall former students in their class 2=recall names from a photo.
       • findings
         • 90% accuracy of photo recall
         • free recall declined with age
       • conclusion
         • face and name recognition are rarely forgotten when cues are given.
         • recognition is better than recall
       • strengths
         • not a lab experiment - mundane realism
         • research was representative of a natural activity. study has high ecological validity - findings can be generalised.
       • weaknesses
         • may have been opportunities to look over the photos in the book. this is rehearsal
   • STM
     • Peterson and Peterson (1959)
       • procedure
         • lab experiment - ppts given a trigram and then a 3-18 second delay where they count back from 300 in threes out loud
       • findings
         • recall decreased steadily between 3 and 18 seconds
       • conclusion
         • the memory trace disappeared after 18 seconds
       • strengths
         • lab experiment - highly controlled. IV - always being manipulated
       • Weaknesses
         • lacks mundane realism - does not reflect how we remember in real life