Types of memory Flashcards
What is memory
memory is the ability to retain information after the original stimulus has passed through the processes of encoding, storage and retrieval
What is encoding
putting something into a code, used to store in a memory trace
What is storage
the result of encoding-the information is stored within the memory system
What is retrieval
recovering stored information form the memory system
What is capacity
how MUCH information can be held in a store
What is duration
how LONG this information can be retained for
What are the three types of memory
- sensory register
- short term memory
- long term memory
Name some facts about the sensory register
- the SR temporarily stores information from our senses
- unless we pay attention to it, it disappears quickly through spontaneous decay-the trace fades
- the SR has a limited capacity and duration
- information is coded depending on the sense that it has picked up-visual, auditory or tactile
Name some facts about short term memory
- limited capacity and limited duration
- coding is usually acoustic (sound)
Name some facts about long term memory
- has unlimited capacity and duration
- is permanent
- coding is usually semantic (the meaning of the information)
- there are three different types of long term memory-episodic, semantic or procedural
Duration of SR-Sperling (1960)-investigated sensory register method
- in a lab experiment, pps were shown a grid with 3 rows of 4 letters for 0.05 seconds
- they then had to immediately recall either the whole grid, or a randomly chosen row indicated by a tone played straight after the grid was shown
Duration of SR-Sperling (1960)-investigated sensory register results
- when pps had to recall the whole grid, they only managed to recall 4 or 5 letters on average
- when a particular row was indicated, pps could recall an average of 3 items, no matter which row had been selected
Duration of SR-Sperling (1960)-investigated sensory registerconclusion
- the pps didn’t know which row was going to be selected so it could be concluded that they would have been able to recall 3 items from any row-almost the whole grid was held in their SR
- they couldn’t report the whole grid because the trace faded before they could finish recall
Duration of SR-Sperling (1960)-investigated sensory register evaluation
- lab experiment-highly scientific and control of variables so could replicate
- artifical setting means it lacks ecological validity-people don’t normally have to recall letters in response to a sound, so the results might not represent what would happen in the real world
Duration of STM-Peterson and Peterson (1959)-trigrams method
- pps were shown nonsense trigrams (3 random consonants e.g. CVM) and asked to recall them after either 3,6,9,12,15 or 18 seconds
- during the pause, they were asked to count backwards in threes from a given number. This was an ‘interference task’ to prevent them from repeating the letters internally
Duration of STM-Peterson and Peterson (1959)-trigrams results
- after 3 seconds, pps could recall 80% of the trigrams correctly
- after 18 seconds, only about 10% were recalled correctly
Duration of STM-Peterson and Peterson (1959)-trigrams conclusion
-when rehearsal is prevented, very little can stay in STM for longer than about 18 seconds
Duration of STM-Peterson and Peterson (1959)-trigrams evaluation
- the resultd are likely to be reliable because lab experiement
- nonsense trigrams are artificial so the study lacks ecological validity
- meaningful or ‘real life’ memories may last longer in STM
- only one type of stimulus was used-duration of STM may depend on the type of stimulus
- each pps saw many different rigrams, which could have led to confusion and only the first trigram was the only realistic trial
Duration of long term memories-Bahrick et al (1975)-very long term memories method
- 392 people were asked to list the names of their ex-classmates (free-recall test)
- they were then shown photos and asked to recall the names of the people shown (photo-recognition test)
- they were given names and asked to match them to a photo of the classmate (name recognition test)
Duration of long term memories-Bahrick et al (1975)-very long term memories results
- within 15 years of leaving school, pps could recognise 90% of faces and names
- they were 60% accurate on free recall
- after 30 years, free recall had declined to 30% accuracy
- after 48 years, name recognition was about 80% accurate and photo recognition was about 40% accurate
Duration of long term memories-Bahrick et al (1975)-very long term memories conclusion
- this study is evidence of very long term memories in a real life seting
- recognitions is better than recall-there may be a high store of information but it’s not always easy to access all of it-you need help to get toi it
Duration of long term memories-Bahrick et al (1975)-very long term memories evaluation
- field experiment-high ecological validity
- in a real life study like this, its hard to control variables, making the findings less reliable-there is no way of knowing whhy information was recalled well
- study showed better recall than other studies on LTM, but this may be beacuse meaningful information is stored better. This type of information could be rehearsed, increasing the rate of recall. This means the results can’t be generalised to other types of information held in LTM
Capacity of STM-Jacobs (1887) method
- pps were presented with a string of letters or digits
- they had to repeat them back in the same order
- the majority of digits or letters increased until the pp failed to recall the sequence correctly
Capacity of STM-Jacobs (1887) results
- the majority of the time, pps recalled about 9 digits and 7 letters
- this capacity increased with age during childhood
Capacity of STM-Jacobs (1887) conclusion
- Jacobs concluded that STM has a limited storage capacity of 5-9 items
- individual differences were found, such as STM increasing with age, possibly due to use of memory techniques such as chunking
- digits may have been easier to recall as there were only 10 different digitd to remember, compared to 26 letters
Capacity of STM-Jacobs (1887) evaluation
- research is artificial and lacks ecological validity-it’s not something you would do in real life
- meaningful information may be recalled better, perhaps showing STM to have an even greater capacity
- the previous sequences recalled by the pps mught have confused them on future trials
What was Miller’s role in STM
- Miller (1956) reviewed research into the capacity of STM. He found that people can remember about 7 items
- He argued that the capacity of STM is 7+/-2 (Miller’s magic number)
- he suggested that we use chunking to combine individual letter or numbers into larger, more meaningful units
- STM could probably hold about 7 pieces of chunked information, increasing STM’s capacity
What is acoustic coding
- how the information sounds
- used in STM, because we try to keep information active by repeating it to ourselves
What is semantic coding
- the meaning of the information
- in LTM, coding is gernally semantic because it’s more useful to code words in terms if their meaningm rather than what they sound or look like
- coding in LTM can also be visual or acoustic
Baddeley (1966)-investigating coding in STM and LTM method
- pps were given 4 sets of words that were either aucoustically similar (man, mad, mat), aucoustically dissimilar (pit, cow, bar), semantically similar (big, large, huge) or semantically dissimilar (good, hot, big)
- independent groups design used
- pps asked to recall the words either immediately or following a 20 minute task
Baddeley (1966)-investigating coding in STM and LTM results
- pps had problems recalling acoustically similar words when recalling the word list immediately (from STM)
- if recalling after an interval (from LTM), they had problems with semantically similar words
Baddeley (1966)-investigating coding in STM and LTM conclusion
-the patterns of confusion between similar words suggest that LTM is more likely to rely on semantic coding and STM on acoustic coding
Baddeley (1966)-investigating coding in STM and LTM evaluation
- lacks ecological validity
- there are other types of LTM and other methods of coding which this experiment doesn’t consider
- independent groups design means no control over participant variables
