coding, capacity & duration

• • Duration refers to the amount of time that information can be stored in each memory store. The duration of STM is 18-30 seconds, as demonstrated by Petersen et al (1959), who found that increasing retention intervals decreased the accuracy of recall of consonant syllables in 24 undergraduates, when counting down from a 3 digit number (preventing mental rehearsal).
• • Capacity refers to the volume of information/data which can be kept in any memory store at any one time. For example, the capacity of STM is thought to be 7 +/- 2 items (Miller), whilst the capacity of LTM is unlimited.
• • Coding is acoustic in short-term memory, and semantic in long-term memory, as demonstrated by Baddeley (1966), who found that more mistakes are made when recalling acoustically-similar words straight after learning them, whilst more mistakes are made when recalling semantically-similar words 20 minutes after learning them (LTM recall).