coding capacity and duration

short-term memory

The phase or the of memory responsible for the temporary storage of information

long-term memory

The phase or type of memory responsible for the storage of information for an extended period of time

coding

The process of converting information between different forms e.g. taking an event and turning it into a memory

You can code information; semantically, acoustically and visually

semantically

the meaning of the information

verbally

how the information sounds

visually

how information can be seen

Baddeley's research; coding

He split participants into 4 groups and created 4 groups of word lists.

- group 1- words sounded similar (acoustically similar group)

- group 2- words didn't sound similar (acoustically dissimilar group)

- group 3- words had similar meanings (semantically similar)

- group 4- words with different meanings (semantically dissimilar group)

Participants were asked to recall the word at different time intervals, immediately after seeing them and then 20 minutes after seeing them.

Baddeley's results

- short-term memory codes acoustically

- long-term memory codes semantically

Baddeley's coding evaluation (+)

- very well controlled, all participants received exactly the same instructions and procedure

- means the experiment is easily repeatable, so is reliable

- this is a strength because both of these are important in making research scientific

Baddeley's coding evaluation (-)

- lacks ecological validity

- the word lists were artificial in the sense that they included random words that do not have specific links to everyday life

- it may be that the STM and LTM coded these lists this way, but in everyday life, it may differ

- this mental Baddeley's work may not link to wider context

capacity

how much information can the STM hold at one time

duration

how long can information be kept in your memory both STM and LTM

Peterson and Peterson (aim)

aim- to investigate the duration of stm

Peterson and Peterson (method)

method- 24 students were tested 8 separate trials. on each trial the student was given a constant to remember. they were also given a three digit number and were asked to count backwards form that three digit number. on each trial they were asked to stop at different times e.g. after 3,6,9,12,15,18. they were then asked to recall the constant

Peterson and Peterson (results)

results- after 3 seconds the average recall was around 80%, after 18 seconds it was about 3%

Peterson and Peterson (conclusions)

conclusion- the results tell us that the duration of short term memory is very short, and the shorter amount of time you have to remember it for, the easier it is to remember/ the more you remember

Jacob (capacity)

he investigated the capacity of memory by measuring the digit span, he said that the mean digit span was between 3 and 9 items

Miller (capacity)

he said that the mean digit span was 7+/- 2, he concluded that we can remember 5 words just as easy as remembering 5 letters and concluded we must do this by chunking

Bahrick et al (aim)

aim- to investigate the duration of LTM

Bahrick et al (method)

method- they studied 392 american participants between 17 and 74, their high school yearbooks were obtained

1. a photo recognition test consisting of 50 photos, some from participants high school year book

2. free recall test where participants recalled all the names of their graduating class

Bahrick et al (results)

results- participants who were tested within 15 years of graduation were about 90% accurate in photo recognition. after 48 years, recall declined to about 70% for photo recognition. free recall was less accurate than photo recognition- about 60% after 15 years and dropping to 30% after 48 years

Bahrick et al (conclusions)

conclusion- LTM decreases over time (duration). the duration of long term memory is improved with a stimulus

Duration evaluation (+)

strength of Bahrick et al research is that it has high external validity, because real life meaningful memories were studied

Duration evaluation (-)

a limitation of Peterson and Peterson research is that its stimulus was artificial, it lacked external validity

a limitation of Bahrick et al research is that the confounding variables are not controlled i.e. unsure when people last viewed their yearbook

Coding evaluation (+)

strength of Baddeley's research is that it identified at clear difference between two memory stores, the idea that the STM codes mostly acoustically and LTM codes mostly semantically is mostly true

Coding evaluation (-)

limitation of Baddeley's research is that it was artificial stimuli used, and due to the words being unimportant to the participants, the processing and information remembered may differ, if the information is important to them

Capacity evaluation (-)

- limitation to Jacob's study is that is was conducted a long time ago, and psychology lacked adequate control of the confounding variables

- limitation to Miller's research is that he may have overestimated the capacity of the STM. Cowan (2001) research showed STM was around 4 not 7 chunks