1
COGNITIVE PSYCHOLOGY
Encoding : turning sensory experiences into an electrochemical form that can be used and
stored by the memory system (creating a memory trace) into the forms:
- Visual
- Acoustic
- Semantic
- Haptic (touch)
- Olfactory
Storage : maintaining and holding electrochemical traces in the memory system whilst it is
being used or for later retrieval
Retrieval : locating and accessing memories from storage
1
, 2
Forgetting No attention Displacement Decay
Decay Interference
Retrieval failure
EVIDENCE FOR SENSORY STORE
2
, 3
Sperling (1960)
A visual array of letters is presented via a tachistoscope for a brief moment and then a
direction is given to recall the whole or a specific row of the array
Average recall = 4.32 letters
If a direction is given to recall a row immediately after the presentation = precise recall
But decays rapidly if there is a delay before the direction
SM can hold a limited amount of information for a few hundred milliseconds before it’s
lost
EVIDENCE FOR STM
Peterson & Peterson (1959)
Duration of STM
Pps recalled 1 trigram of 3 consonants after n+3 s intervals, then were
given a number from which they had to count backwards in 3s’
After 3s = 90 % correctly recalled
After 18s= 2 % correctly recalled
Evidence for existence of STM, its limited duration and the need for
rehearsal to prevent decay
Miller (1956)
Capacity of STM
Refined to 7+/- 2 items or slots in which information can be stored
Baddeley (1966b)
Pps presented with 4 lists of words and were asked to recall them
immediately after (STM) and after 20 minutes (LTM)
Lists of words
1. Acoustically similar
2. Acoustically dissimilar
3. Semantically similar
4. Semantically dissimilar
They found it difficult to remember acoustically similar words in STM but
this had little effect in LTM
STM mainly uses acoustic encoding
Semantically similar words caused confusion in LTM (fewer were recalled)
3
, 4
LTM uses mainly semantic encoding
EVIDENCE FOR LTM
Bahrick et al. (1975)
Duration of LTM
400 pps between 17-74 yrs
Series of memory tests on names and faces of students in pps’ high
school years
Identification of names+faces =
90 % accurate within 15 yrs of leaving high school
70-80% accurate after 48 yrs
Brady et al. (2008)
Capacity of LTM
Showed pps 2500 objects over the course of 5.5 hrs
They were shown pairs of objects and were asked to identify which 2
objects they had seen
Original object+Different one=92%
original+Similar object= 88%
Original object depicted from a different angle = 87 %
-thousands of images can be maintained successfully
Glanzer and Cunitz (1966): Serial Position Effect
(Primacy - Recency effect)
Aim: investigate the distinction between STM and LTM
Whether the position of word in a list affected recall
Research method: Laboratory experiment
Procedure: pps were presented with a list of words (greater than the capacity of STM), one
at a time; then were asked to recall them in any order (free recall)
Condition 1 : immediate free recall
4
COGNITIVE PSYCHOLOGY
Encoding : turning sensory experiences into an electrochemical form that can be used and
stored by the memory system (creating a memory trace) into the forms:
- Visual
- Acoustic
- Semantic
- Haptic (touch)
- Olfactory
Storage : maintaining and holding electrochemical traces in the memory system whilst it is
being used or for later retrieval
Retrieval : locating and accessing memories from storage
1
, 2
Forgetting No attention Displacement Decay
Decay Interference
Retrieval failure
EVIDENCE FOR SENSORY STORE
2
, 3
Sperling (1960)
A visual array of letters is presented via a tachistoscope for a brief moment and then a
direction is given to recall the whole or a specific row of the array
Average recall = 4.32 letters
If a direction is given to recall a row immediately after the presentation = precise recall
But decays rapidly if there is a delay before the direction
SM can hold a limited amount of information for a few hundred milliseconds before it’s
lost
EVIDENCE FOR STM
Peterson & Peterson (1959)
Duration of STM
Pps recalled 1 trigram of 3 consonants after n+3 s intervals, then were
given a number from which they had to count backwards in 3s’
After 3s = 90 % correctly recalled
After 18s= 2 % correctly recalled
Evidence for existence of STM, its limited duration and the need for
rehearsal to prevent decay
Miller (1956)
Capacity of STM
Refined to 7+/- 2 items or slots in which information can be stored
Baddeley (1966b)
Pps presented with 4 lists of words and were asked to recall them
immediately after (STM) and after 20 minutes (LTM)
Lists of words
1. Acoustically similar
2. Acoustically dissimilar
3. Semantically similar
4. Semantically dissimilar
They found it difficult to remember acoustically similar words in STM but
this had little effect in LTM
STM mainly uses acoustic encoding
Semantically similar words caused confusion in LTM (fewer were recalled)
3
, 4
LTM uses mainly semantic encoding
EVIDENCE FOR LTM
Bahrick et al. (1975)
Duration of LTM
400 pps between 17-74 yrs
Series of memory tests on names and faces of students in pps’ high
school years
Identification of names+faces =
90 % accurate within 15 yrs of leaving high school
70-80% accurate after 48 yrs
Brady et al. (2008)
Capacity of LTM
Showed pps 2500 objects over the course of 5.5 hrs
They were shown pairs of objects and were asked to identify which 2
objects they had seen
Original object+Different one=92%
original+Similar object= 88%
Original object depicted from a different angle = 87 %
-thousands of images can be maintained successfully
Glanzer and Cunitz (1966): Serial Position Effect
(Primacy - Recency effect)
Aim: investigate the distinction between STM and LTM
Whether the position of word in a list affected recall
Research method: Laboratory experiment
Procedure: pps were presented with a list of words (greater than the capacity of STM), one
at a time; then were asked to recall them in any order (free recall)
Condition 1 : immediate free recall
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