duration coding and capacity

Peterson and Peterson research about duration

The student was given a consonant syllable to remember they were also given a 3 digit number the students counted backwards to prevent any mental rehearsal of the constant syllable

They were told to stop after periods of time (3, 6, 9, 12 seconds )

Finding- after 3 seconds average recall was about 80% after 18 secs it was about 3% these findings suggest that STM duration was about 18 secs unless info was repeated over and over

What is duration?

Refers to the length of time I do can be held in memory

A limitation of duration research

Artificial way

The study is not completely reliant because we do sometimes try to remember fairly meaningless material and recalling constant syllable,e do not reflect most everyday memory activities

A strength of duration research

Practical application

Demonstrates how inference in the form of verbal distractions can affect our ability to retain information

Eg: when we are revising for exams we should take care to avoid distractions

What is baddley research on coding

He investigated acoustic and semantic encoding in STM and LTM

Gave 4 words listed to pps to learn

1. Acoustically similar( eg; sat, cat , mat )

2. Acoustically dissimilar(eg; foul deep soul )

3. Semantically similar (eg; huge large big )

4. Semantically dissimilar (eg: one day computer )

They had to recall them in correct order either immediately after to test STM or 20 mins to test LTM

Findings when pps recalled the words immediately they tended to do

What is coding?

The way info is stored in memory the main ways are:

• Acoustically (by sounds)

• Systematically (by meaning)

A limitation of baddley study on coding?

Baddley waited 20 mins to test them for LTM recall

Was this long enough?

Evaluation point for coding ?

A strength and weakness

As a lab study it is well controlled allowing us to establish cause and effects but this does compromise ecological validity

The study used artificial stimuli rather than meaningful material (eg; ingredients for a cake) which means we have to be cautious when generalising results

What is capacity?

This refers to the amount of info STM can hold at one time and is represented in bits of info such as digits

Millers research for capacity

Argued the span of immediate memory 7+/ - 2 units of info

We can cope with memorizing 7 pieces of info but not more than this

However miller noted we can remember 5 words just as well as 5 letters

They do this by chunking - grouping common sets of digits or letters into units or chunks

A strength of capacity research

Individuals differences

Capacity of STM is different for everyone digit span improves with age because changed in brain capacity

A limitation of Jacob’s study in capacity

Jacob’s study was carried out a long time ago early psychological research had little control so pps could of been distracted and this would act as a confounding variable