Memory- SM, STM and LTM
Terms in this set (19)
A temporary storage system that holds unprocessed information.
How much your memory can hold.
How long a memory lasts for, before it is no longer available.
The way information is changed so that it can be stored in the memory.
Short term memory
Your memory for immediate events. It has limited capacity and duration.
Long term memory
Your memory for events that happened in the past. It has unlimited duration and capacity.
Capacity of SM: Sperling's Research
Participants saw a 3x4 letter grid flash up for 1/20 of a second (relying on their sensory memory). They then heard a tone to indicate which row had to be recalled.
Recall was high which suggested ionic (visual) memory has a large capacity.
Duration of SM: Walsh and Thompson's Research
Iconic store- Average duration = 500 milliseconds. It decreases with age.
Brief duration of sensory memory allows people to focus on what they need and forget what they don't need.
Coding of SM: Crowder's Research
Sensory memory only retains information in an ionic store for a few milliseconds. It retains information in an echoic store for 2-3 seconds.
Sensory memory contains different stores, maybe even sub-stores.
Capacity of STM: Miller's Magic Number
P's given list of random number digit strings e.g. 549
they were asked to recall them in order. 6912
Became difficult to recall digit strings, most people had an immediate digit span (IDS) of 7+/-2.
Evidence shows average IDS is 7+/-2.
Duration of STM: Peterson & Peterson
To test how long STM lasts when rehearsal is prevented
P's shows consonant trigram e.g. CVB, they were asked to count back in 3's from a specific number. After intervals of 3,6,9,12,15 and 18 seconds they were asked to recall trigram. Repeated several times with different trigrams.
P's able to remember 80% of trigrams after 3 second interval. Less than 10% of p's able to remember after 18 seconds.
Reitman- "limited duration of STM is due to new info displacing old info. Artificial testing of STM= meaningless- doesn't reflect real life.
Factors affecting duration of STM
- items disappear from STM when rehearsal is prevented.
Deliberate intention recall
-info vanishes from STM in seconds if people don't make a conscious effort to retain it.
Factors affecting Capacity
-Influence of LTM- Bower & Winzenz
=capacity of STM increased.
-Pronunciation time- Schweickert and Boruff
= pronunciation in 1.5-2 seconds.
Chunking- a way to improve capacity of STM, limited to 4 chunks, size of it matters and the older you are the more you can remember.
Coding in the STM: Baddeley
To explore effects of acoustic and semantic coding.
p's asked to recall acoustically similar and dissimilar words and semantically similar and dissimilar words.
Acoustically similar words were harder to remember using STM. Semantically similar/dissimilar words didn't affect STM.
STM relies heavily on acoustic coding.
Capacity of LTM
There is no research for capacity of LTM, because memories can last a lifetime, so its impossible to quantify a capacity. LTM is like a 'filing cabinet' because its highly organised and info is easy to retrieve.
Duration of LTM: Bahrick et al
To see whether VLTM exists and if its affected by recognition/ recall.
Group of high school graduates were shown pictures of classmates from their year book and they were asked to recall their names. The other group weren't shown pictures, they just had to recall their names.
Recognition group- 90% recall after 14yrs of leaving, 80% after 25yrs, 75% after 34yrs.
People remember certain types of info over a lifetime.
VLTM is better when measure in recognition tests.
Unsure whether decline is due to limits of duration or decline with age.
Very long term memory
Known as a perma-store for VLTM
Factors affecting duration of LTM
-children don't have the ability to retain info until age 3.
How duration is measured
-recall/ recognition/ stimulus
-Bahrick & Hall
Coding in the LTM: Baddeley et al
To explore effects of acoustic and semantic in LTM
P's asked to recall acoustically similar and dissimilar words and semantically similar and dissimilar words. Each list of words were 10 words long and p's tested after an interval of 20 mins.
p's recalling from LTM- recall was worse for semantically similar and dissimilar words. Recall for acoustically similar and dissimilar words was the same.
LTM relies primarily on semantic coding.