Peterson and Peterson (1959) Duration of STM
investigated how different short term intervals containing an interference task affect the recall of items
Study 24 students were given a 48 nonsense constant syllable to remember and a 3-digit number to count backwards for 3, 6, 9, 12, 15 or 18 seconds to prevent repition
Students recalled, on average, about 80% of the syllables correctly with a 3-second interval
wheras 18 seconds only 10%
Average recall after 18 seconds fell to about 3%
Duration of STM without rehearsal is about 18-30 seconds
If we are unable to rehearse information, it will not be passed to the LTM, providing further support for the MSM and the idea of discrete components