Memory:
What is Memory:
● Cognitive psychologists believe that human behaviour can be best explained if we first
understand the mental processes that underlie behaviour
● It is, therefore, the study of how people learn, structure, store, and use knowledge
○ Essentially, how people think about the world around them
● Based on the computer model
○ Input → processing → output
● Memories are astounding in their capacity:
○ Infants learn on average 10 words a day
○ Adult vocabulary can contain over 100,000 words
○ Memory has preserved our species
■ Key to our survival has been the ability of one generation to pass along
insights, innovations and experiences to the next so they can improve upon
them
● Human memory can most broadly be defined as the process by which we retain information
about events that have happened in the past
● Memory is important as it is vital for learning and remembering tasks even like catching a bus
● Short-term memory:
○ Information that we process and recall straight away is usually stored in our STM →
stores information we are currently aware of
○ When we take in new information to store, we must process it from sensory input
■ We take in information from the senses and transform it into a memory
trace (coding)
○ When we experience sensory information, it stays there just long enough to decide if
we should process it further
■ If we don’t attend to or rehearse it, then we forget it
■ If we do ‘rehearse’ it, it will transfer to our STM (limited capacity store)
● Long-term memory
○ Continual storage of information which is largely outside of our awareness, but can
be recalled when needed
○ If you attend long enough to information in the STM, it can be transferred to your
LTM
○ LTM has a potentially unlimited capacity and can hold information for years until we
want to retrieve it
, Coding, Capacity, and Duration:
● Coding: the format in which the information is stored in memory
● Capacity: the amount of information held in a memory store
● Duration: the length of time information can be held in memory
Type Encoding Capacity Duration
Sensory Sense-specific - Unknown, but very Very limited,
raw/unprocessed large approximately 0.5
information from all 5 seconds
senses
STM Mainly acoustic, Limited, 7+/-2 ‘chunks’, Limited, 18-30
Baddeley (1966) Jacobs (1987), Miller seconds, Peterson &
(1956) Peterson (1959)
LTM Mainly semantic, Unlimited Unlimited - lifetime,
Baddeley (1966) Bahrick (1975)
● George Miller (1956) conducted similar experiments and argued that on average, we can
recall 7 items (plus or minus 2) with a range of between 5 - 9 items
○ We can remember more as long as we break information down into 5 - 9
manageable chunks
● The digit span test → developed by Jacobs (1887)
○ Researcher gives a number of digits and participant has to recall them in order
○ The researcher then increases the amount by 1 digit and the participant has to recall
again until they cannot recall the correct order → determines their digit span
○ The mean digit span was 9.3 items, for letters, it was 7.3 letters
● The Peterson task (1959) → participants given 3 consonants and 3 digits, e.g. THX 512
○ They had to recall the consonants after a delay in which they counted backwards in
3s from their 3 digit number
■ Interference - prevented participants from rehearsing in between recalls
● LTM → Bahrick et al. (1975)
○ Tested 400 people between ages of 17 - 74 for their memories of classmates
○ 50 photos - 1) identify their classmates, 2) recall their names
○ Within 15 years - 1) 90%, 2) 60%
○ After 48 years - 1) 70%, 2) 30%
● Coding - how is data stored
○ Our memory needs some way in which data can be stored (coding)
■ 1) Acoustically - sounds
■ 2) Visually - images
■ 3) Semantically - meaning
○ Acoustically similar but semantically different:
■ Cat, can, cab, cap, mad, mat, map
○ Semantically similar but acoustically different:
■ Great, large, big, huge, broad, tall, high, wide
○ Alan Baddeley (1966) used word lists like those to test coding in STM and LTM
