3.2 Models of Memory (Multi-store Model)

What is Memory?

Memory refers to the processes by which we encode, store, and retrieve information over time.

Memory for humans

Mental Capacity allows to remember:

• past experiences - learn from them

• use knowledge to guide behaviour in present and future

who first proposed the multi-store model

Atikinson and Shifrin 1968

Multi-store model

Three separate components:

• Sensory

• Short-term

• Long-term

  Each has its own capacity and duration

  To move to next store, certain conditions required

Sensory Model

Sensory memory doesn’t store or process info

Detect info and hold it for STM or lost

Components of Sensory memory

Several sub components:

• Visual

• Auditory

• Olfactory etc.

  • most research focused iconic and echoic memory

Stats for sensory

Limited by perception

Duration is short (iconic: 1 second / echoic: 2-5 seconds)

Stats for STM

STM: 7(+-2) units of information / duration = dependent of modality but no longer than 30 seconds

If unattended, fades away after 30 seconds

To move to LTM - rehearsal

Stats for LTM

Large amount of info for indefinite amount of time

Unlimited and unlimited

However, not easily retrievable

Limitations of MSM

• The model is over-simplified. It assumes that each of the stores works as an independent unit

• Does not explain memory distortion

Peterson and Peterson aim

Peterson and Peterson aimed to investigate the duration of the short-term memory and provide empirical evidence for the multi-store model.

Peterson and Peterson year

1959

Method

True Laboratory Experiment

Design

Repeated Measures Design

Sampling Strategy

Convenience; 24 psychology students

IV

Time delay before recall

DV

Recall accuracy of trigrams

Procedure 1

Participants asked to recall trigrams (e.g. TGH) after intervals of 3,6,9 - 18)

Procedure 2

During interval, backwards in 3’s - prevent rehearsal
Repeated several times with different trigrams

Findings 1

Longer interval - less recall
80% - 3 seconds
10% - 18 seconds

Conclusion 1

Short-term mem - limited duration when rehearsal is prevented
Info lost due to trace delay
Support difference between STM and LTM

Supports MSM

What study should be used with Peterson and Peterson for ERQ question on models of memory

Baddeley et al.

Baddeley et al. Year

1975

Aim

To investigate the effect of word length on short-term memory capacity, supporting the phonological loop

Method

True Laboratory experiment

Design

Repeated Measures design

Sampling strategy

Opportunity sampling; 72 participants

IV

Length of words

DV

Number of words correctly recalled in order

Procedure 1

Ppts shown a list of 5 words: either 1 syllable or 5+ syllables

Procedure 2

Asked to immediately recall them in order

Repeated with different word lists

Findings

Short words were recalled significantly better than long words

Number of words recalled matches what could be spoken in 1.5-2 seconds (word-length effect)

When rehearsal was suppressed, world length effect disappeared

Conclusion

STM capacity is limited by time, not number of items

People can recall as many words as they can say in 2 seconds

Supports phonological loop.