Coding, capacity and duration of memory

Coding, capacity and duration of memory

1. Research on coding

   • If participants were asked to recall them after 20 minutes, the did worse with semantically similar words. Suggests information is coded semantically in LTM.
   • Participants shown original words and asked t recall in correct order.
   • Baddeley gave different list of words to 4 groups of participants.
   • Once information gets into the memory system, it is sored in different formats. this formation of converting information from one form to another is called coding.

2. Research on duration

   • STM- duration is about 18 seconds.
   • LTM- duration is up to a lifetime.
   • Peterson and Peterson (1959) study used artificial material that don't reflect our everyday memories.

3. Research on capacity

   • Digit span
     • Jacobs (1887) developed a technique to measure digit span.
     • The researcher for example, gives 4 digits and the participant is asked to recall these in the correct order out loud. If this is correct the researcher will then read out 5 digits and so on until the participant cannot recall the order correctly.
     • This determines the persons digit span. The mean span or digits was 9.3 items and the digit span for letters was 7.3
   • Span of memory and chunking
     • Miller (1956) made observations of everyday practice. E.g. he noted that things come in sevens: there are 7 notes on the music scale.
     • This suggests that he span for capacity of STM is about 7 items +/- 2.
     • However, Miller also noted that people can recall 5 words as well as 5 letters. They do this by chunking- grouping sets of digits or letters into units or chunks.

4. Evaluation

   • Lacking validity- could be extraneous variables such as distractions.
   • No so many chunks- Cowan: estimates STM as about four chunks.
   • Meaningless stimuli- used consonant syllables.
   • Higher external validity- meaningful real life memories, showed greater recall that LTM studies with meaningless material (Shephard.)