Lesson 1 - STM and LTM Flashcards
What does STM stand for?
Short term memory
What is short term memory?
This type of memory stores and allows recall of information for a period of several seconds and up to 30 seconds without rehearsal. Its capacity is very limited
What does LMT stand for?
Long term memory
What is long term memory?
This type of memory stores and enables us to recall information from the more distant past. Its capacity is unlimited and the duration is potentially a lifetime
In what three ways do the STM and LTM differ?
Duration
Capacity
Coding
What does duration mean?
How long a memory lasts before it can no longer be recalled
Explain Peterson and Peterson’s study
Participants were presented with a consonant trigram (eg BQT)
They were asked to count backwards in threes to stop them from repeating/ rehearsing.
After intervals of 3, 6, 9, 12, 15, and 18 seconds, participants had to stop counting and repeat the trigrams.
Was repeated using different trigrams.
What were the findings of Peterson and Peterson’s study?
Participants could remember about 90% of trigrams after 3 seconds, 20% after 9 seconds and 2% after 18 seconds.
Thus the duration of the STM is 20 seconds without rehearsal as was shown in Peterson and Peterson’s study.
Strengths of Peterson and Peterson’s study?
- Lab experiment; tightly controlled with the manipulation of the IV and control of extraneous variables
- Can be replicated; standard procedures
Weaknesses of Peterson and Peterson’s study?
- Experiment has low ecological validity as we do not recall trigrams in everyday life.
- Trigrams presented on earlier trials may have caused confusion when participants came to remember trigrams in later trials
How did Bahrick test LTM duration?
Tested how well 392 American high school graduates could remember their for,ear classmates names using tests such as asking them to identify pictures, matching names to pictures and recalling names with no picture cues.
What did Bahrick find out?
Even after 48 years, when asked to link names to faces, the accuracy was about 70%, which suggests the duration of the LTM is potentially a lifetime.
The study also showed that recall of name was only accurate when shown pictures of their faces suggesting that we need cues to remember things in the past.
Strengths of Bahrick’s study?
Natural experiment; high ecological validity because tasks given to participants were real
Weaknesses of Bahrick’s study?
- Experimenter had less control and thus extraneous variables being more of an issue since participants may have still been in contact with their classmates
- The study showed we could remember names but doesn’t really focus on other types of information and not all LTMs remain forever
What is the capacity of memory?
The measure of how much information cN be held in memory
