coding capacity duration

who are the researchers and studies for capacity ?

Jacob’s - digit span technique

Millers - magic number 7

weakness of Jacob’s study - 1887

P- conducted in 1887

E-psychological research had less control so more EV’s

A- reduced internal validity

H- further research supported limited capacity of STM

Another weakness of Jacob’s - task

P- task has low mundane realism

E- digit span used letters and numbers

A- less ecological validity

Weakness of research into capacity

P- Both overestimated capacity

E- other research found 4

A- original findings invalid

outline research into coding

Baddely-

different memory stores code information

List of acoustically similar words and immediate recall

Strength of research into coding

P- clear difference in memory stores

E- STM acrostic LTM semantically

A- led to the MSM

Strength of coding research

P- controlled experiment

E- lab study controlled EV eg they all received a hearing test

A- increases internal validity

H- artificial task which were word lists and low ecological validity

research into duration of STM

Peterson and Peterson

given constant trigrams and 3 digit numbers which were recalled after a wait time of (3,6,9,12,18) and were asked to count backwards from 3 digit number

after 3 secs - 80% after 18 secs - 3%

STM has a short duration of under 18 sec if verbal repetition is prevented. Rehersahl is important to hold onto information

Research into duration of LTM

392 people completed a photo recognition test where they were shown 50 people and identified who they were. And a free recall test where they had to name all who they could remember.

Photo recognition- 15years 90% 48years 70%

Free recall- 15years 60% 48years 30%

If we avoid dementia or Alzheimer’s duration of LTM is lifelong

Evaluation of STM duration

P- artificial stimuli

E- trigrams aren’t representative

A- low mundane realism and ecological validity

H- lab study highly controlled

Evaluation of LTM duration

P- real life memories used

E- used pictures of real life classroom since when meaningless recall lowers

A- high mundane realism and external validity

H- EV’s as they may often look at yearbook