lecture 8- short and long term memory Flashcards
(16 cards)
Three basic memory systems:
Sensory memory
Short term/ working memory
Long-term memory
sensory memory
1) Sensory memory: just seeing and perceiving the subject, recording of the perceptual experience
- Iconic memory: holds visual input for 250 msec, literal record of the percept without meaning or interpretation
- Echoic memory: holds auditory input for 2-3 seconds, an analyses if it should be passed to short term memory
○ Crucial to understand and processing of the information
short term/ working memory
understanding of the subject
- lasts a few seconds to a minute
- Can hold a limited amount of information
- Codes in different ways, auditory, visual or semantic codes to better organise it
Long term memory
long term memory of the information
- Stores vast amounts of information to up to a lifetime.
- Personal experiences, knowledge and skills
- Encodes information semantically
Sperlings 1960 iconic memory research:
Whole report procedure: Flash a matrix of letters and digits for 50 milliseconds
- Participants remembered 4 items
Partial report procedure: flash a matrix for 50 milliseconds and ask participants to report items in one row
- Able to report any row
Study of capacity and duration of sensory memory
The capacity of iconic memory is limited
The free recall task
Participants given a list of 10-15 words
Asked to recall them in any order
Plot the results according to how well the words were recalled at each serial position
Showed the primary effect, ability to recall words at the beginning of the list especially well and regency effect- words at the end
- The effects on a graph where x axis is serial position and y axis is % remembered shows memory recall is influenced by items position on a list
- Our brain processes information differently at the beginning and end of a list, creating a u shaped curve
- Delaying the recall of the last few items can reduce or eliminate the regency gradient
If the primary gradient remains but the regency gradient is no longer present:
Means the individual is distracted or nut fully engaged during the retention interval, limiting their ability
Free recall task with filled delay
- Included a filled delay between last item and recall and participants undertake secondary activity (eg counting backwards)
- This was able to reduce or eliminate the regency effect
○ Primary effect is the result of long term memory and regency of short-term memory
- This was able to reduce or eliminate the regency effect
What is the capacity of short term memory?
Digit span test:
- Present a sequence of numbers that increases in length after each successful recall
- It can be adapted to assess other aspects of short term memory and is a useful tool
- 7 items +/-2
Short term memory is thought to be based on a phonological (verbal) code and is like an inner voice
Evidence for phonological coding in short-term memory Baddeley 1966:
The phonological similarity effect is a phenomenon where words that sound alike are more difficult to recall than those that sound different
- First observed in 1966 and replicated in subsequent studies
- Thought to be related to the way information is processed and stored in the phonological loop
Word length effect: recall of words is worse for longer words than shorter one.
- This disappears when phonological coding is prevented through articulatory suppression such as counting or repeating an irrelevant word)
Classical/ modal memory model:
Consists of 3 stages, sensory, short term and long term memory which briefly stores information from the senses before being discarded or transferred to short term memory
- Short term memory stores a limited amount of information for up to 30 sec and is likely to be forgotten if not rehearsed
Information that is rehearsed and processed deeply is transferred to long term memory where it can be stored indefinitely
Baddeley’s working memory model:
- Information we receive from senses first enters sensory memory where it is either forgotten or transferred to working memory
- When we pay attention to the information, it is directed to the central executive which is responsible for coordinating and controlling our cognitive processes.
- From there information can be temporarily stored in the visuo-spatial sketch pad or to our long-term memory
Or it can be directed to the phonological loop which processes verbal information through 2 components: the articulatory control and phonological store
Duration of long-term memories:
Standing 1973: participants recognised 133 out of 160 pictures shown randomly form a pool of 10000 pictures,
- Indicating a long-term memory trace of about 6600 pictures
- Suggesting recognition for pictures is almost limitless and pictures are better recognised than words
Paivo’s dual coding hypothesis: pictures can convey more information than verbal descriptions in certain situations.
- Words that are imageable can be encoded in visual and non-visual forms
- However the value of a picture depends on context
High imageability words like apple are better remembered than abstract words like idea
Further evidence of semantic coding in long-term memory:
Baddeley: semantically similar words are more easily remembered.
- In one study, participants were given a list of semantically related and a list of not semantically related words.
- Participants were better able to recall the semantically similar words
Implicit vs explicit memory:
implicit: where behaviour indicated that memories are being retrieved without a deliberate and conscious effort to retrieve them (procedural memory, recognising meaning of common words)
Explicit: also known as declarative memory where retrieval requires conscious recollection
Organisation of semantic memory:
and moses illusion
- Retrieval time from a semantic memory is dependent on the distance between the concepts in the memory
- Collins et al proposed a hierarchical model of semantic memory organisation where concepts that are more general are at the top, and more specific at the bottom.
The moses illusion is where individuals answer a question incorrectly due to a failure to apply stored knowledge, it depends on semantic similarity
- Collins et al proposed a hierarchical model of semantic memory organisation where concepts that are more general are at the top, and more specific at the bottom.
