The multi store model (Atkinson, & Shiffrin 1968) describes memory in terms of in-
formation flowing through a system. Accordingly, it can be described as an informa-
tion processing model (like a computer) with an input, process and output.
1. External stimuli first enter the sensory memory in an uncoded form where they
can be registered for very brief periods of time; in order for information to be
passed into the short term memory store attention is vital.
2. Information from the STM is transferred to the long-term memory only if that
information is rehearsed. Rehearsal was initially described by Atkinson and
Shiffrin as maintenance rehearsal, but Shiffrin later suggested that rehearsal
could be elaborative (Raaijmakers, & Shiffrin, 2003).
3. If rehearsal does not occur, then information is forgotten, lost from short term
memory through the processes of displacement or decay.
HOW IS IN- Evidence - Primacy and Recency Ef-
DURATION CAPACITY ENCODING FORMATION fect (Serial Position Effect) by Mur-
LOST? dock (1962)
sense specific Procedure
all sensory ex- (e.g. Murdock asked participants to learn a list
SENSORY perience (v. storesdifferent
¼ to ½ second larger for each Decay of words that varied in length from 10 to
MEMORY capac- sense 40 words and free recall them. Each word
ity) was presented for one to two seconds.
15-30 seconds mainly audi-
SHORT (unless re- Results
TERM peated or re- 7 +/- 2 items tory/acoustic Decay or Dis- - He found that the probability of recalling any word depended on its posi-
hearsed) code placement tion in the list (its serial position).
MEMORY
- Words presented either early in the list or at the end were more often re-
called, but the ones in the middle were more often forgotten. This is known
Mainly Se- as serial position effect.
LONG
Unlimited Unlimited mantic (but Decay, Inter-
TERM can be visual ference, Re- The improved recall of words at the beginning of the list is called the primary
MEMORY and auditory) trieval Failure effect; that at the end of the list, the recency effect. This recency effect exists
even when the list is lengthened to 40 words.
Evaluation