Memory - Coding, Capacity and Duration of Memory Flashcards
What is memory?
The process by which we retain information about events that have happened in the past.
Explain coding
- Encoding is the way that information is changed so that it can be stored in memory
- Short Term Memory codes information acoustically - by the way it sounds
- Long Term Memory codes information semantically - by what it means
- Coding is the format in which information is stored in the various memory stores
What was the research into coding?
Baddely 1966
He gave different lists of words to 4 groups of Ps to remember, and the mistakes made show the encoding in the part of memory
Group 1 - acoustically similar: words sounded similar e.g. cat and can
Group 2 - acoustically dissimilar: words sounded different e.g. few and pit
Group 3- semantically similar: words with similar meanings e.g. great,large,big
Group 4 - semantically dissimilar: words that had different meanings e.g. big, huge, hot
What were the short term memory findings of the coding research?
- When asked to recall words straight away, group 1 had the worst recall - suggesting that information is encoded acoustically in STM
- STM gets confused when it has to retrive words acoustically similar as the words get muddled up - meaning that fewer words are remembered
- STM can still retrive semantically similar words because STM pays no attention to what the words mean, meaning there’s no confusion by words with the same meaning
What were the long term memory findings of the coding research?
- When asked to recall words after 20 mins group 3 had the worst recall - suggesting that information is encoded semantically in LTM
- LTM gets confused by similar meanings
Explain capacity
- Capacity is how much information can be stored in each memory store
- The capacity of the STM is 5-9 items
- Capacity of the LTM is potentially unlimited
What was the research done into STM capacity?
Jacobs 1887
* Developed a technique to measure digit span
* For example, the researcher gives 4 digits and then the P is asked to recall the digits in the correct order out loud
* If the P recalls them correctly, then the researcher reads out 5 digits and so on until the P cannot recall the order correctly - determining the P’s digit span
Miller 1956
* People can recall 5 words as well as they can recall 5 letters
* This created the idea of chunking which is grouping sets of things together
* Examples: ADU, FDN…
What were the findings into Jacob’s capacity study?
- Average span was 9.3 for numbers and 7.3 for letters
- 8 year olds could recall an average of seven digits
- By the age of 19, recall had increased to nine digits
Jacob’s study provides evidence that the capacity of STM is between 5-9 items
What was the research done into LTM capacity?
Wagenaar 1986
* Created diary of 2400 personal events in his life over 6 years and tested him on the recall of events rather than dates
* Did this based on 4 memory cues - what,when,who,where
* He added a critical detail of each event and events were rated on distinctiveness, pleasentness and emotional involvement
Findings
He had excellent recall with no events being completely forgotten, suggesting the capacity of the LTM is very large
Explain duration
- The period of time information can last in the memory stores
- Duration of STM: 18-30 seconds
- Duration of LTM: upto a lifetime
What was the research done into STM for duration?
Peterson and Peterson 1959
* Tested 24 students who took part in 8 trials - on each trial the student was given a nonsense trigam e.g. YCG and a 3 digit number to remember
* The student had to count back from the 3 digit number until they were told to stop as it prevented any mental rehersal
* On each trial the student was told to stop at different times like 3,6 or 9 seconds - retention interval
Findings
As the retention interval increased, Ps found it harder to remember the trigams, suggesting that the STM has a very short duration unless something is repeated over and over again through verbal rehearsal
What was the research done into LTM for duration?
Bahrik 1975
* Studied 392 Ps from Ohio in America who were aged 17-74
* Ps highschool yearbooks were obtained and recall was tested in 2 ways
* Photo recognition test: Name as many people as you can from 50 year book photos
* Free recall test: Recall all names of individuals in the yearbook without any cues
Findings
* Photo recognition was 90% accurate after 15 years and 70% accurate after 48 years
* Free recall was 60% accurate after 15 years and 30% accurate after 48 years - suggesting LTM has a very long duration if appropriate cues are provided like photos
