Short And Long Term Memory Flashcards
Define the term capacity in terms of memory
Capacity concerns how much data can be held in a memory store. STM is a limited capacity whereas LTM has a potentially unlimited capacity
What did Joseph Jacob’s discover
Jacobs used digit span which was used to measure capacity of STM. He found that the average span for digits was 9.3 items and 7.3 letters. He said it was easier to recall numbers as there was only 9 digits but there are 26 letters.
What did george miller do
Miller wrote a memorable article called the magic number 7+/-2, in which he reviewed psychological research and concluded that the span of immediate memory is about 7 items- sometimes a bit more, and sometimes a bit less.
What research went into discovering the duration of STM
Loyd Peterson and Margaret Peterson (Peterson and Peterson) studied the duration of STM using 24 students. Each participant was tested over eight trials. On each trial a participant was given a consonant syllable and a 3 digit number (eg- THX 512) they were asked to recall the consonant syllables after a retention interval of 3,6,9,12,15 and 18 seconds. And during the interval they had to count back from their 3 digit number (preventing maintenance rehearsal) participants on average were 90 percent correct over 3 seconds, 20 percent after 9 seconds and only 2 percent correct after 18 seconds. This suggests that STM has a very short duration of around 18-20 seconds.
What research went into studying the duration of LTM
Harry bahrick et al tested 400 people of various ages (17 to 74) on their memories of their class mates after leaving high school. A photo recognition test consisted of 50 photos, some front the participants high school yearbook. In a free recall test the participants were asked to recall the names they could remember from their class. After 15 years people were 90 percent accurate in identifying faces, and after 48 years, this declines to about 70 percent. Free recall was about 60 percent accurate after 15 years, and dropping to 30 percent fêter 48 years. This showed that duration of LTM is potentially unlimited.
How did Alan Baddeely study acoustic and semantic coding to determine what type of coding is better for each memory store
-the following words are acoustically similar, but semantically different
Cat, can, cab, cap, map. Max
-the following words are semantically similar but acoustically different
Great, large, big, huge, broad
Alan baddely used word lists like these and found that participants had difficulty remembering acoustically similar words in STM but not in LTM, whereas semantically similar words posed little problem for STM but led to muddled LTM. This shows that STM is largely encoded acoustically and LTM is largely encoded semantically.
