Short and long term memory Flashcards
What is long term memory (LTM)?
The memory if events that have happened in the past. Can last between 2 minutes to 100 years. It is potentially unlimited duration and capacity.
https://www.youtube.com/watch?v=iPEog8Wd8po
What is short term memory (STM)?
Your memory of immediate events. STM lasts for a very short time and disappears unless it is rehearsed. It has a limited duration and a limited capacity. STM is also known as WM (working memory).
What is ‘chunking’?
Miller proposed that the capacity of STM can be enhanced by grouping sets of digits together into meaningful ‘chunks’. For example it is easy to remember 1846 1632 than 18461632. Miller believed that we can remember 7 +/- 2 chunks at a time. In addition the size of the chunk may effect how many chunks can be processed.
What are the three types of memory?
*Sensory memory (SM) *Short-term memory (STM) *Long term memory (LTM)
Why are not many studies done on sensory memory?
SM is not often studied because sensory memory does not last long due to spontaneous decay.
What is the meaning of duration?
How long a memory lasts before it’s no longer available
What is the meaning of capacity?
How much can be held in memory. It is measured in bits of information, such as the number of digits.
What is the meaning of encoding?
The act of transferring information into code, creating a ‘trace’ (so it is stored in your memory). Information enters your brain via your senses and is stored in different ways… *Visual codes (such as pictures) *acoustic form (sound) *semantic form (the meaning of the experience)
Does STM have a limited capacity and duration?
Yes, it only stores information for a short time.
Does LTM have a limited capacity and duration?
No, your long term memory has an unlimited capacity and can hold information permanently.
What was the method that Peterson and Peterson used to investigate STM?
A group of participates were shown nonsense trigrams of 3 random consonants and asked to recall then after either 3,6,9,12,15 or 18 seconds. During the wait the participants were asked to count backwards in threes from a random number (this was a ‘interference task’ to stop them from repeating the letters to themselves).
https://www.youtube.com/watch?v=fD6LT2osVkE
What is memory?
A process in which information is retained about the past
When did Peterson and Peterson investigate the duration of STM?
1959
What were the results for Peterson’s and Peterson’s investigation?
*After 3 seconds participants could recall about 80% of trigrams correctly *after 18 seconds about 10% of the trigram was recalled successfully
What was the conclusion of the Peterson and Peterson investigation?
When rehearsal in prevented, very little can stay in STM for longer than about 18 seconds
What did they evaluate from the Peterson and Peterson investigation?
The results were likely reliable because it was conducted in a laboratory where the variables can be tightly controlled. However, the study lacked ecological validity as the trigrams were artificial. In addition meaningful or real-life memories may last longer in STM. Only one type of stimulus was used (the duration of STM may depend on the stimulus). Lastly, each participant saw multiple trig grams meaning that they could have gotten confused, resulting in the first trig gram being the only reliable one.
When did Bahrick et al study VLTMs (very long term memories)?
1975
What was the method of Bahrick et al’s study of VLTM?
- participants were asked to list the names if there ex-classmates (free-recall test).
- Next they were shown photos of the classmates and asked to recall the name of that person (photo-recognition test).
- or they were given names of there classmate and asked to match it with the picture (name-recognition test).
What were the results of Bahrick et al’s study?
- They were about 60% accurate on free recall after 15 years
- After 30 years of leaving school free-recall had declined to about 30% accuracy
- after 48 years, name-recognition was about80% accurate, and photo-recognition as about 49% accurate.
What was the conclusion of Bahrick et al’s study on VLTMs?
Recognition is better than recall. This may mean that we have a huge storage of information but it is not always easy to access it. However we may remember after receiving prompts (be it audio or visual).
What was Jacobs conclusion?
Jacob concluded that STM had a limited storage capacity of 5-9 items. STM increased with age, possibly because of the increased brain capacity and the better use of memory techniques such as chunking. Digits may have been easier to recall as there are only 10 digits compared to 26 letters (the whole alphabet).
What was Baddeley’s evaluation?
His study lacked ecological validity and does not test other types of LTM (e.g episodic memory and procedural memory) and other methods of encoding (e.g visual). The experiment used an independent group design, so there wasn’t any control over participant variables.
https://www.youtube.com/watch?v=I4pRSQpuJqo
What did peterson and peterson investigate?
The duration of STM
What did Jacobs study?
The capacity of STM
What did Bahrick et al study?
The duration of VLTM’s (very long-term memories)
What did Miller study?
Capacity of LTM
What did Miller propose?
That most people can remember 7+/-2 (i.e 5-9) digits or chunks in there STM.
What are the ways that sensory memory is coded?
- Iconic (visual)
- Haptic (touch)
- Echoic (sound)
- Olfactory (smell)
- Gustatory (taste)
https://www.youtube.com/watch?v=xUzPG4187Hg
What were Conrad’s findings?
Participants found it more difficult to recall acoustically similar letters.
What was Conrad’s experiment?
Participants were shown a sequence of 6 consonants on a screen. There were two conditions:
- Letters which were acoustically similar (B,C,G)
- or letters which were acoustically dissimilar (e.g. F,J,X).
Participants were then asked to recall the words.
How did Luria investigate the capacity of LTM?
Luria studied a Russian journalist called Solom Shereshevesky who appeared to have a limitless memory capacity.
