memory Flashcards
(110 cards)
define memory
Memory is the process of retaining information after the original thing is no longer present
define coding
Format in which memories are stored
define duration
The length of time information can be held in memory
define capacity
The amount of information that can be stored
capacity of sensory register…
unlimited
duration of sensory register….
250 milliseconds
coding of sensory register…
modality specific
capacity of short term memory…
7+/-2
duration of short term memory…
18-30 seconds
coding of short term memory…
acoustic/ sound based
capacity of long term memory…
unlimited
duration of long term memory…
potentially forever
coding of long term memory…
semantic
what were the researches on capacity of STM
1.-Joseph Jacobs (1887) measured capacity of the STM using digit span.
-Jacobs found that the mean span for digits across all participants was 9.3.
-the mean of span of letters was 7.3
2.-George Miller (1956) observed that many items in life come in groups of 7.
-Believed capacity of STM was 7 items ± 2
-noted that people can recall 5 words as easily as they could recall 5 letters( through chunking)
a strength of Jacob’s study on capacity of STM
-it has been replicated
-The study is a very old one and early research in psychology often lacked adequate controls.
-e.g. some participants’ digit spans might have been underestimated because they were distracted during testing (confounding variable).
-Despite this, Jacobs’ findings have been confirmed by other, better controlled studies since (e.g. Bopp and Verhaeghen ).
-This suggests that Jacobs’ study is a valid test of digit span in STM.
a limitation of Miller’s research on capacity of STM
-he may have overestimated STM capacity.
-Cowan reviewed other research and concluded that the capacity of STM is only about 4 (plus or minus 1) chunks.
-This suggests that the lower end of Miller’s estimate (five items) is more appropriate than seven items.
define chunking
grouping sets of digits or letters into units/chunks
What is the evidence for acoustic encoding in STM and semantic encoding in LTM?
.Baddeley gave participants four lists of words to learn:
-Acoustically similar
-Acoustically dissimilar
-Semantically similar
-Semantically dissimilar
.recalling from STM had worse results for acoustically similar words
.recalling from LTM had worse results for semantically similar words
-so info in coded acoustically in STM and semantically in LTM
evaluation 1- artificial stimuli ( research on coding)
-limitation
-didn’t use meaningful material.
-The word lists had no personal meaning so Baddeley’s finding may not tell us much about coding in different memory tasks.
-When processing meaningful info, people may use semantic coding for STM tasks.
-This suggests these findings have a limited application.
evaluation 2- separate memory stores ( research on coding)
-strength
-it identified a clear difference between two memory stores.
-The idea that STM uses mostly acoustic coding and LTM mostly semantic has stood the test of time.
-This is an important step in understanding the memory model which led to MSM.
what was the research on duration of STM?
-Peterson and Peterson used consonant syllables and a filler task of counting backwards for differing lengths of time. The amount they could recall showed the duration of STM
-found that recall was about 80% after 3 seconds and 3% after 18 seconds
what was the limitation of Peterson and Peterson’s study on duration of STM
-stimulus material was artificial.
-The study is not completely irrelevant because we do sometimes try to remember fairly meaningless material (e.g. phone numbers).
-recalling consonant syllables does not reflect most everyday memory activities where what we are trying to remember is meaningful.
-This means the study lacked external validity.
what was the research on duration of LTM?
-Bahrick conducted a yearbook study and recall was tested through (1) photo recognition recall and (2) free recall test
-within 15 years of graduation there were about 90% accurate in photo recognition recall and 60% in free recall
-after 48 years it dropped to about 70% in photo recall and 30% in free recall
what was the strength of Bahrick’s study on duration of LTM
-it has high external validity.
-the researchers investigated meaningful memories i.e. of people’s names and faces.
-When studies on LTM were conducted with meaningless pictures to be remembered, recall rates were lower (e.g. Shepard 1967).
-This suggests that Bahrick’s findings reflect a more real estimate of the duration of LTM.