Short- and long-term memory (Keywords (Short-term memory- your memory for…
Short- and long-term memory
STM may not be exclusively acoustic
Baddeley may not be have tested LTM
Acoustic & semantic coding
The following words are the opposite - semantically similar but acoustically different: great, large, big, huge, broad, long, tall, fat, wide, high
The following words are acoustically similar but semantically different: cat, cab, can, cad, cap, mad, max, mat, man, map.
STM results may be due to displacement
Testing STM was artifical
The duration of LTM
90% accurate in identifying faces. After 48 years, this declined to about 70% for photo recognition. Free recall was about 60% accurate after 15 years, dropping to 30% after 48 years
List the names they could remember of those in their graduating class
A photo recognition test consisted of 50 photos, some from the participant's high-school yearbook
Harry Bahrick et al. tested 400 people of various ages (17-78) on their memory of classmates
The duration of STM
STM has a very short duration - less than 18 seconds - as long as verbal rehearsal is prevented
Participants on average, were 90% correct over 3 seconds, 20% correct after 9 seconds and only 2% correct after 18 seconds
Peterson and Peterson told participants to recall consonant syllable after a retention interval of 3,6,9,12,15 or 18
The size of the chunk matters
The capacity of STM maybe be even more limited
The magic number 7+-2
People can recall five words as well they can recall five letters- we chunk things together and can then remember more
The span of immediate memory is about seven items - sometimes a bit more
George Miller wrote about the magic number seven plus or minus two
the capacity of STM
Span for digits was 9.3 items and 7.3 for letters
Joseph Jacobs used this technique to assess STM capacity
Assessed using digit span
Short-term memory- your memory for immediate events. STMs are measured in seconds and minutes rather than hours and days, i.e. a short duration. They disappear unless they are released. STM also has a limited capacity of about four items or chunks and tends to be coded acoustically. This type of memory is sometimes referred to as working memory
Long-term memory (LTM)- your memory for events that have happened in the past. This lasts anywhere from 2 minutes to 100 years. LTM has potentially unlimited duration and capacity and tends to be coded semantically.
Duration- a measure of how long a memory lasts before it is no longer available
Coding- (also 'encoding') The way information is changed so that it can be stored in memory. Information enters the brain via the senses (e.g. eyes and ears). It is then stored in various forms, such as visual codes (like a picture), acoustic codes (sounds) or semantic codes (the meaning of the experience).
Capacity- this is a measure of how much can be held in memory. It is represented in terms of bits of information, such as number of digits.