Coding, Capacity and Duration

Coding

The format in which information is stored in a memory store.

Capacity

The amount of information that can be held in a memory store.

Duration

The amount of time information can be held in a memory store.

Baddeley's research on STM coding

- acoustically similar/dissimilar words

- semantically similar/dissimilar words

- had to recall words straight after learning

- had to recall 20 minutes later

- found ppts did worse on acoustically similar words straight after, and worse on semantically similar words after 20 mins

- STM codes acoustically, LTM semantically

Jacob's research on STM Capacity

- digit span test

- would increase amount of digits ppts had to recall based on if they correctly recalled previous

- found that ppts recalled around 9 digits, and 7 numbers

Miller STM Capacity

- 7 +/- 2 items

- chunking

Peterson & Peterson research on STM Duration

- consonant syllable/trigram

- ppts given a group of random letters to recall

- had to count backwards to avoid recall

- had to recall at different times (3s, 6s, 18s etc.)

- recall after 3s = 80%

- recall after 18s = 3%

- STM has a duration of 18 seconds

Bahrick's research onf LTM Duration

- tested ppts recall of classmates

- photo recognition and free recall of names

- ppts tested after 15 years had 90% accuracy in photo recognition, after 48 years it was 70%

- Free recall found 60% accuracy, then 30% accuracy

- LTM can last a lifetime

Evaluation Points - Baddeley

+ supports separate memory stores

- artificial stimuli

Evaluation Points - Jacobs

+ valid and reliable as it has been replicated

Evaluation Points - Miller

- Cowan found capacity to be lower at 4 +/- 1

Evaluation Points - Peterson & Peterson

- artificial stimuli

Evaluation Points - Bahrick

- high ecological validity using meaningful stimuli