Short term memory

Short term memory

1. Duration

   • Peterson and Peterson (1959). Participants were asked to recall the consonant trigrams after differing lengths of time. Experimenters said out load a triagram and paritipants had to try and remember it
   • Time were allowed between recall - 3 ,6 ,9 ,12 ,18 seconds
   • Findings- About 90% of trigrams were recalled after a 3 second retention interval but only 5% after 18 seconds. This shows that STM has a limited capacity of less than 30 seconds
   • - Lacks ecological validity as it was conducted in a lab. This means it is not representative to a real life setting
     • - Methodology flawed, asked a range of different trigrams in each trial so this could have led to confusion so interference would have affected their data

2. Capacity

   • Miller (1956) Paticipants were asked to recall digits in lab conditions. Findings- Participants recalled between 5-9 digits.
   • Digits were recalled better than letters. STM memory span increased with age. Type of information does not determine span which is fairly cosistent in individuals
   • The STM has a limited storage capacity of between 5-9 items. This can be improved with techniques such as chunking
   • _ Lacks ecological validity as it was not representative to a real life setting. For example, memories are not normally involving numbers
     • + Findings have been usefully applied to improving memory. This means the research although it was in a lab, impacted the real world

3. Encoding

   • Baddeley (1966) Lab experiment to examine whether encoding is primarily acoustic or semantic. 75 Participants were presented with one of four lists repeated four times.
   • List A - Acoustically similar words - 'cat' 'mat' List B- Acoustically dissimilar words - 'pig' 'day' List C- Semantically similar words - 'huge' 'big' List D- Semantically dissimilar words - 'hot' 'safe'
   • Findings- participants given List A (accoustically similar words) performed the worst, with a recall of only 10%. They confused similar sounding sounds such as recalling 'cap' instead of 'cat'. Recalling the other lists can be compatiely good at between 60%-90%
   • Conclusion- since list A was recalled the least effectively, it seems there is acoustic confusion in STM, Suggesting STM is encoded on an acoustic basis
   • + Baddeley's findings make 'cognitive sense'. For example, if you had to remember a shopping list, you would repeat it aloud (acousitic rehearsal)
   • - This was a lab experiment and therefore shows causality (cause and effect relationships) but may lack ecological validity (not representative to real life activities)