Cognitive Psychology

STM Duration: In order to investigate how long information can be held in the STM, Margaret and Lloyd Peterson(59) tested 24 undergraduates.8 trials: students given consonant syllables and a 3-digit number.

Procedure:They had to count backwards from their 3-digit number(tostop mental rehearsal of their consonant syllable) and on each trial they were told to stop after a different amount of time: 3,6,9,12,15 or 18 seconds(retention interval)

Evaluation: the longer the retention interval, the more incorrect responses were made. STM has a short duration unless we rehearse information  for example verbal rehearsal. The limitation of peterson and peterson's study is that the stimulus material was artificial and does not reflect real life situations so this experiment might be lacking external validity. howver, we do try to remember fairly meaningless things, such as phone numbers, so the study is not all wrong. Another limitation is that the STM is limtied capacity however at the time the peterson and peterson did…