Short and Long term Memory Flashcards
Features of STM: Capacity, Duration, Coding Features of LTM: Capacity, Duration, Coding
Define Short-term Memory (STM)
The limited capacity memory store.
In STM, coding is mainly acoustic (sounds), capacity is between 5 and 9 items on average, and duration is about 18 seconds.
Define Long-term memory (LTM)
The permanent memory store.
In LTM, coding is mainly semantic (meaning), it has unlimited capacity and can store memories for up to a lifetime.
What is coding?
Information is stored in memory in different forms, depending on the memory store. The process of converting information between different forms is called coding.
What is capacity?
The amount of information that can be held in a memory store
What is duration?
The length of time information can be held in memory
Who provided research for encoding?
Alan Baddeley
What did Alan Baddeley give his four groups of participants to remember?
Group One: Acoustically similar: (Words sounded similar)
Group Two: Acoustically dissimilar: (Words sounded different)
Group Three: Semantically similar: (words with similar meanings)
Group four: Semantically dissimilar ( words with different meanings)
What were the participants tasked with in Alan Baddeley?
Participants were shown the original words and asked to recall them in the correct order.
What happened when the participants in Baddeley’s experiment did the task immediately?
When they did this task immediately, recalling from the short-term memory, they tended to do worse with acoustically similar words.
What do the finding of Baddeley’s suggest?
The findings suggest that information is coded acoustically in STM and semantically in LTM.
What happened when the participants in Baddeley’s recalled the list after a time interval of 20 minutes?
When they recalled the word list after a time interval of 20 minutes recalling from the long-term memory they did worse with the semantically similar words.
What did Joseph Jacobs find?
Joseph Jacobs found out how much information the STM can hold at one time. He did this by measuring digit span.
What is the mean digit span?
Joseph Jacobs found that the mean span for digits across all participants was 9.3 digits. The mean span for letters was 7.3.
How is digit span found?
The researcher would read 4 digits, the participant would recall, then 5 digits and so on until the participant cannot recall the order correctly.
What is the span of memory?
Miller came forward with the idea of a Magic number 7 (plus or minus two).
What does Magic number 7 provide evidence for?
It provides evidence for the capacity of short term memory.
How many items can be stored in an adults short term memory?
Most adults an store between 5 and 9 items in their short term memory.
Who conducted a study to investigate the duration of short-term memory?
Peterson and Peterson conducted a study to investigate the duration of short-term memory.
What were the participants tasked to do in the Peterson and Peterson study?
They conducted an experiment in which 24 participants (psychology students) had to recall trigrams.
What are trigrams? 9Peterson and Peterson)
Meaningless three-constant words
How did Peterson and Peterson prevent rehearsal in their participants?
To prevent rehearsal, participants were asked to count backwards in threes or fours from a specified random number until they saw a red light appear.
When were the participants asked to recall trigrams (Peterson and Peterson)?
Participants were asked to recall trigrams after intervals of 3, 6, 9, 12, 15, or 18 seconds.
What were the findings of the investigation of the duration of STM in Peterson and Petersons experiment.
They found that a the longer the interval delay the less trigrams were recalled.
Stats of Peterson and Peterson duration of STM experiment?
Participants were able to recall 80% of trigrams after a 3 second delay. However, after 18 seconds less than 10% of trigrams were recalled correctly.
What was the conclusion made from Petersons and Petersons experiment?
Short-term memory has a limited duration when rehearsal is prevented. It is thought that this information is lost from short-term memory through decay (trace decay).
Who conducted a study to investigate the duration of the long-term memory?
Bahrick (1975)
What was the participant sample in Bahrick’s study?
Bahrick used 392 American university graduates.
What were the participants in Bahrick’s study tasked with?
The graduates were shown photographs from their high-school yearbook and for each photograph participants were given a group of names and asked to select the name matched that matched the photographs.
What were Bahrick’s findings?
Bahrick found that 90% of the participants were able to correctly match the names and faces, 14 years after graduating and 60% of the participants were able to correctly match the names and faces 47 years later.
What did Bahrick conclude?
Bahrick concluded that people could remember certain types of information, such as names and faces for almost a llfetime.
What does Bahrick’s study provide evidence for?
Bahrick’s results support the multi-store model and the idea that our long-term memory has a lifetime duration (at least 47 years) and is semantically encoded).
What is a strength of Alan Baddeley’s research?
It has high internal validity due to the controlled laboratory conditions, which minimised extraneous variables and allowed for clear conclusions about encoding differences, and reinforcing the distinction between STM and LTM.
What is a limitation of Alan Baddeley’s research?
A limitation is its low ecological validity, as memorizing word lists in a lab does not reflect real-world memory tasks. Additionally, the study may over simplify memory processes by focusing solely on encoding, neglecting other factors like retrieval and storage.
What is a strength of Joseph Jacobs’ research?
A strength of Joseph Jacobs’ research is that it was one of the first systematic studies of STM capacity an dit laid the groundwork for later research including Miller’s (1956) theory of 7 plus or minus 2 items.
What is a limitation of Peterson’s and Peterson’s study?
One limitation of Peterson’s and Peterson’s study is that it lacked external validity. The stimulus material was artificial. Study is not completely irrelevant because we do sometimes try to remember fairly meaningless material.
