Baddeley (1966): The influence of acoustic and semantic similarity on long-term memory

Baddeley (1966): The influence of acoustic and semantic similarity on long-term memory

1. Aim

   • To determine how long-term memory is affected by semantic and acoustic encoding

2. Procedure

   • 3 experiments conducted
   • Men and women from the Applied Psychology Research Unit Subject Panel
   • Assigned 1 of 4 list conditions
   • Independent groups
   • Lab experiment

3. Experiment 1

   • Ppts attempted to learn 1 of 4 lists of 10 words
     • Lists were either acoustically or semantically similar or control words of equal frequency
   • Lists learned for 4 trials
     • After which, the ppts were given a 20 minute digit memory task
       • Then asked to recall the word list

4. Experiment 3

   • 4 lists of 10 words
     • List A: 10 acoustically similar words
     • List B: 10 acoustically dissimilar words matched in terms of frequency of everyday use to List A(control group)
     • List C: 10 semantically similar words
     • List D: 10 semantically dissimilar words - matched in terms of frequency of everyday use to List C (control group)
   • 4 groups of ppts
   • Shown 10 words - 3 seconds each
     • Distractor task - 6 tasks involving memory of digits
       • Given words and asked to recall in order in 1 minute
         • Results gathered - evidence for STM
           • Repeat stages 1-4 X 4 - learning trials - LTM
             • 15 minute interference task - copying 8 digit sequences
               • Surprise recall test of 10 words - order
                 • Results gathered - evidence for LTM

5. Results

   • Recall of List A lower than recall of List B - not significant difference
     • No difference for C and D
     • Acoustic encoding was initially difficult
       • But didn't affect long-term recall
   • Recall of List C was 55% accurate and List D was 85% accurate - significant difference
     • No difference for A and B
     • LT recall was a lot worse for semantically similar words than semantically dissimilar words
       • Semantically dissimilar words are unrelated and aren't likely to be mixed up in recall

6. Conclusion

   • Later retest recall of List 3 was impaired compared to all other lists because they were semantically similar
     • Suggesting that LTM is largely but not exclusively semantic
   • Because recall of acoustically similar words were initially more difficult to encode
     • Suggests that STM is largely acoustic

7. Evaluation

   • Strengths
     • Men and women used
       • No gender bias
     • Highly controlled lab experiment
       • Standardised procedure
       • timing of visual stimulus
     • Can be applied to dementia and dyslexia
     • No order effects (independent groups)
     • Ethics
       • No deception
       • Debriefed
       • No physical harm
   • Weaknesses
     • Small sample
     • All from USA
     • Individual differences
     • Low ecological validity
       • Unnatural setting
       • Tasks required are artificial
     • Ethics
       • possible embarrasment
       • psychological harm