Baddeley (1966b) - Classic Study

• Aim of the Baddeley Study

  The aim of the study was to determine how long term memory is affected by semantic and acoustic encoding. Also the aim was to see if short term memory and long term memory are encoded differently. 
• Procedure of the Baddeley Study (What the Lists compose of)

  Four lists of 10 words were used: 

  List A contained 10 acoustically similar words 

  List B contained 10 acoustically dissimilar words that were matched in terms of frequency of everyday use to List A 

  List C contained 10 semantically similar words 

  List D contained 10 semantically dissimilar words that were matched in terms of frequency of everyday use to List C 

  List B and D acted as baseline control groups for List A and C.
• Procedure of the Baddeley Study

  1)Each list of 10 words was presented via projector - 1 word every 3 seconds in the correct order.

   2)After ppts were required to complete 6 tasks involving memory for digits. 

  3) Then asked to recall the word list in 1 min by writing down the sequence in the correct order. 

  4)This was repeated over 4 learning trials. The word list in random order was made visible on a card. 

  5) Next, the groups were given a 15 min interference task involving copying 8 digit sequences at their own pace. 

  6)Then there was a surprise retest on the word list sequence.
• Findings of the Baddeley Study

  • For semantically similar words recall was 55% accurate
  • For semantically dissimilar words recall was 85% accurate
  • No difference in recall for acoustically similar and dissimilar words.
  • Recall of the acoustically similar sounding words was worse than the dissimilar sounding words during the initial phase of learning (trial two in particular).  - STM
  • Long-term recall was a lot worse for semantically similar words compared to semantically dissimilar words.
  • There was no difference in the long-term recall of acoustically similar or dissimilar words.
• Conclusion of the Baddeley Study

  The fact that participants found it more difficult to recall list one in the initial phase of learning suggests that short-term memory is largely acoustic (phonological loop), therefore acoustically similar sounding words were more difficult to encode.

  Later retest recall of list three was impaired compared to all other lists because they were semantically similar; suggesting that encoding in long-term memory is largely, but not exclusively, semantic.