Classic study Baddeley

• Baddeley studys aim was To investigate whether the LTM encodes acoustically (based on sound) or semantically (based on meaning). This is done by giving participants word lists that are similar in the way they sound (acoustic) or their meaning (semantic); if the participants struggle to recall the word order, it suggests LTM is confused by the similarity which means that this is how LTM tends to encode.
• The method used by baddeley was an experiment where he gave participants two different types of words; one set were phonologically related (sounded alike) and another set were semantically related (meaning wise)
• baddeleys conclusion from his research was that LTM stores information based on its meaning rather than its sounds
• Aim:

  To investigate whether LTM encodes acoustically (based on sound ) or semantically (based on meaning). This was done by giving word lists to the participants which were either similar in terms of sound or meaning. If a participant was struggling to recall  the word order baddley suggested that LTM is confused by similarities which means that this is how LTM tends to encode
• Independent variable

  1. acoustically similar or acoustically dissimilar word list
  2. Semantically similar or dissimilar word list
  3. Testing short term memory performance before 15 minutes interference task and then testing LTM performance after task

  Independent variable 1 and 2 use independent groups design but independent variable 3 is tested through repeated measures 
• Dependent variable 

  Score on recall test of 10 words, words must be recalled in correct order
• Sample

  Mixed groups of men and women from applied psychology research unit, Cambridge University. Total participants: 72 men and women
• Group A: acoustically similar list - 15 participants 

  • man,cab,can,cad,cap,mad,max,mat,cat,map
• Group B control: acoustically dissimilar list - 20 participants 

  • pit,few,cow,pen,sup,bar,day,hot,rig,bun
• Group C: semantically similar list - 16 participants 

  • great,large,big,huge,broad,long,tall,fat,wide,high
• Group D control: semantically dissimilar list 21 participants 

  • good,huge,hot,safe,thin,deep,strong,foul,old,late
• procedure

  • word sequences were presented on screen, 1 word per slide, shown for 3 seconds 
  • After participants did interference task; digits read at a 1 second rate, participants allowed 8 seconds to write correct sequence 
  • Tested recall through participants remembering 10 word sequences from first task, had 1 minute
  • After 4th trial participants had 15 min break, asked to do unrelated interference task; self paced digit copying 
  • unexpected 5th test participants asked to recall word lists again, words still on display, longer interference task was to ensure final retest was testing LTM
• Independent groups design- participants only took part in one group A,B,C or D
• • acoustically similar words seemed to be confusing at first shown by poorer performance when compared with control but by test 4 acoustically silicate words performed better than control. However this was not statistically significant 
• • LTM was not confused but acoustic  similarities as scores on last test were similar to fourth trial suggesting no forgetting took place between trial 4&5
• • Semantically similar words seemed confusing and experimentalgorip showed poorer performance than control (statistically significant). Experimental group does not outperform control at all and performs worse overall than acoustically similar. Little forgetting between trials 4&5 but scores are lower
• Conclusion 

  • learning of word sequences was significantly impaired by semantic similarities 
  • LTM and STM work together- transferral to the LTM involves an intermediate stage where material is in STM, this was shown by greater difficulty in learning list when STM is minimised
  • LTM and STM are different- LTM and STM are affected differently by different types of encoding
  • LTM condoning may rely on semantic cues and STM encoding may rely on acoustic cues