STM and LTM Flashcards
capacity of STM
magic 7 plus/minus 2
Duration of STM
18 - 30 secs peterson and peterson
Encoding of STM
acoustic (sound) Braddley
Capacity of LTM
unlimited
Duration of LTM
unlimited bahrick
Encoding of LTM
Semantic
definition of STM
a memory of events in the present or in the immediate past
Definition of LTM
an event that happened in the distance past
Evaluation of LTM
Over simplistic: long-term memory are more complex than the multi store model suggests. For example, There are many different types of long-term memory (e.g. semantic, episodic and procedural) that are stored and processed in completely different ways.
Evaluation of STM
- Cowan’s (2001) had done studies on Capacity of STM and concluded STM is likely to be limited to 4 chunks
- Jacob found that recall ( digit span) increased steadily with age as research shows 8 year old - 6.6 digit and 19 year old - 8.6 digits
- testing STM is artificial. This study is completely irrelevant because we try to remember rarely meaningful memory. As trying to memorise constant syllables does not truly reflect most everyday memory activities where what we are trying to remember is meaningful. This means this study lacks ecological validity.
the study of duration of STM
peterson and peterson
studies using 24 students
each participant was studied over 8 trials
on each trial, participant was given a constant syllables and a 3 digit number
they were asked to recall the constant syllables after a retention interval of 3, 6, 9, 12, 15 or 18 seconds
findings of the duration of STM
90% got it correct over 3 secs
20% correct after 5 seconds
2% after 18 seconds
study of the duration of LTM
Bahrick et al tested 700 people of various ages from 17 to 74 years old from
a photo recognition test considered of 50 photos, some from the high school year book and also a free recall test where participants recalled of the all the names who graduated.
- 90% accurate were ppl who were tested with 15 years of graduation
- 70% after 48 years old.
Recall was less accurate then photo recognition
- 60% after 15 years
- 30% after 48 years.
Shows ltm would last time a lifetime
types of LTM
eposidic, semantic and procedural memory
procedural memory
remembering an action
procedural are typically aquired by repetition and practise
eposidic memory
autobiographical memory
semantic memory
remembering factual and meaningful memory
Evaluation for types of LTM
One strength is evidence from the famous studies HM and Clive wearing. Episodic memory for both these men had been severely impacted due to brain damage. But their semantic memory were relatively unaffected. They still understood meanings of words. Their procedural memory is also intact. They both knew how to walk and speak. Clive wearing knew how to read music, sing and play piano.
Conflicting neuroimaging evidence.
One limitation is that there are conflicting research findings that linking types of LTM to areas of the brain. Buckner and Petersen received evidence regarding the location of semantic and episodic. They concluded that semantic memory is on the left side of the prefrontal cortex and episodic on the right. However other research links the left prefrontal cortex with encoding of episodic memory and right prefrontal cortex with episodic retrieval. This challenges the neurophysiological evidence to support types of memory as there is poor agreement where each type might be.
