Please enable JavaScript.
Coggle requires JavaScript to display documents.
Short-term memory (Y1) - Coggle Diagram
Short-term memory (Y1)
What is memory?
The ability to hold and transform information
- Memory components - encoding, storage and retrieval - duration and capacity
-> Encoding - coding information to be stored / changing its format
-> Storage - maintenance of information
-> Retrieval - recollection of information
Different memories - sensory
- A very temporary sensory register that allows input from the sensory modalities to be prolonged
Different memories - working
- The system in which information is held and manipulated to perform a task
- Different memories - long -term
- The system where information is held for longer periods and can be accessed when needed
Path of external information - sensory input -> sensory memory (attention, unattended information lost) -> short term memory (maintenance rehearsal to maintain, anything not rehearsed decays) -> (encoding) long term memory -> retrieval back to short term memory
Main difference between short term and working memory - working memory is active, short term memory is passive - does not just collect information, it also manages it
-
Sensory memory
- A very temporary sensory register that allows input from the sensory modalities to be prolonged in order for us to attend or process the important parts of that
- E.g. perceiving a large amount of visual information that decays rapidly and only a portion of it remains available to consciousness (Sperling, 1960)
- Type of memory store (Wundt, 1899)Large capacity that fades rapidly What we attend to stays, everything else is gone Involves memory for stimuli as opposed to memory for ideas (Cowan, 2008)
Has some modality specific stores for senses -
- Iconic (visual) -
-> Partial v whole lists - Sperling’s experiments (1980) - whole report, could only remember 4-5 out of 12 items, but in a partial list could remember 3 out of 4 items - visuo-spatial sketchpad - as array size increased, and thus there were more letters in each partial condition, there was an increase in letters recalled - potential large capacity
-> Sperling - speed of decay - partial report advantage disappears after half a second Visual experience not a direct reflection of reality, allows us to see a sequence of motion pictures and animation
- Support - Haber and Standing (1969) - found that when an interval is longer than a quarter of a second between stimuli presentation, participants can see a gap, but any less and they cannot, showing how long the snapshot of iconic memory is
- Examples - computer monitor - refreshing rate of > 60 Hz is better for iconic memory
- Examples - lightning; not continuous but consists of separate strokes with gaps of 40-50 msec (Uman, 1986) - iconic memory lasts much less time - cloud to ground lightning from the sky down, but we see what comes up from the ground - that is our memory of lightning
Echoic (auditory) -
- Darwin - auditory stimuli - partial report of 5-9 items without delay, 4.25 items with a 4 sec delay interval - stimulus persistence lasts a few hundred msec (Massaro, 1970)
- Shadowing (Glucksberg and Cowan, 1970) - one passage to an ear to attend, but ignore the second passage to other ear, but attend digits in the second passage - repeat back a message in first ear, but unattended ear had digits they had to recall - duration between presentation of digit and light cue manipulated, deteriorated at about 4 seconds
- Shadowing (Treisman, 1964) - one passage to an ear to attend, the passages can be the same but are only recognisable if they occur within 2 seconds of each other
- Phonological loop - limited capacity
- Acoustic register - auditory presented information can be prolonged so that some aspects of the input can be retained for processing
- Lower capacity but longer duration than iconic store
- Short tones are prolonged in echoic memory so that they were perceived by participants as lasting longer than they actually were - echoic persistence
Haptic - tactile or touch
- Bliss - associate a letter to each of three sections of the four fingers
- Partial report from one of the three sections - stimulus persistence lasts about a few hundred msec
Sensory memory phases - Cowan, 1988
- Phase one - short term and pre-perceptual, lasts 250 msec
- Phase two - long and involving substantial process, some secs
Sensory memory disruption -
- Backward masking - disrupting transition from sensory memory to short-term memory using mask - mask is an irrelevant stimulus in spatial or temporal proximity given immediately after target stimulus
- Recognition increases if the stimulus onset asynchrony (SOA) increases - SOA of 250 msec needed for recognition Also suggests that shorter duration of echoic memory
Short term memory
Holds information consciousness
- Temporary store of active information with limited capacity
- Much of the information is not retained, and allows us to move to the next task
- Atkinson and Shiffrin’s model of memory (multi-store memory model) - 1973
- Sensory register -> short term memory -> long term memory - sequential, linear, separate stores
- Control processes in STM - rehearsal (received from sensory memory through selective attention)
-> Maintenance rehearsal - repeating to keep information
-> Elaborated rehearsal - encoding to send information to long term memory
- Control processes - decay; information being lost because of time-based limitation
- Control processes - displacement - information lost because of a capacity based limitation
- Model made distinctions between permanent, structural aspects of memory and flexible control processes which vary depending on task requirements
Assumptions - There are separate STM and LTM stores (unlimited capacity and duration, semantic coding)
- Processing in the STM determines memory storage in the LTM STM is a limited capacity store (limited duration and acoustic coding)
Limited STM
Miller (1956) - 5-9 items in digit span
- Cowan (2000) - only 4 items can go from sensory memory to STM
- Chunking - grouping items, like credit card numbers, increases the STM capacity
Serial position curve -
- Primacy effect - recalling items from the beginning of the list, reflecting LTM
- Asymptote - middle serial input position and lowest recall probability
- Recency effect - recalling items from the end of the list, reflects STM and decays after a distractive task
- In amnesic patients, STM is intact, but LTM is impaired - intact recall for items presented at the end of a list (normal recency effect) while memory was impaired for other list items
Dissociating STM from LTM - acoustic coding in STM and semantic in LTM
- Negative recency effect - recalling items from the beginning of the list in multi-list tasks - poorer recall of end list items
- Patients with amnesia (Baddeley and Warrington, 1970 and 1973) - double dissociation of function, where there is deficient LTM but intact STM, but deficient STM meant intact LTM
- Patients with epilepsy (Scoville and Milner, 1957) - removal of bilateral medial lobes including ⅔ of hippocampus and amygdala - deficient STM but intact LTM
KF - impaired STM and language issues after damage to left parieto-occipital regions, but had intact LTM (Shallice and Warrington, 1970) - however, more pronounced issue of auditory memory, struggling with verbal stimuli such as words and digits but sound recognition was unimpaired
- Multi-store model fails to explain how LTM can remain intact despite losing the section of memory which transfers information into the LTM - this would suggest KF has intact working memory
Jonides and the mind and brain of STM -
- Condemned amnesic patient evidence because the conclusions are based on spatial binding related to the hippocampus, but non-spatial binding remains intact
- Also, many still have intact WM - LTM is impaired, showing that they are different systems, but WM being fully intact suggests connections may be what is more damaged
- STM tasks activate similar brain areas to LTM tasks; however, activation does not equate to use in memory, as many areas may be triggered but then not used for the task
- Jonides et al’s model consists of 5 psychological and 6 biological assumptions about neurobiological processing levels
Working memory
- Workbench of human cognition (Klatzky, 1980)
- Collection of mental processes that permit information to be held temporarily in an accessible state, in the service of some other mental task (Cowan, 1998)
- Is the focus of attention (James, 1890)
- Is temporary activated information about our current goals and plans (Miller)
- Is a sensory-specific multi component storage for short-term storage and processing (Baddeley and Hitch, 1974)
- Working memory model - representation of the working memory in STM
Cowan's embedded process model -
- A capacity-limited focus of attention and a temporarily activated subset of LTM, which is modality free
- Capacity limited attention enclosed within time limited active memory inside the LTM
Three components -
- Time-limited active memory - temporarily activated information that is not yet accessible to conscious awareness
- Capacity-limited focus of attention - memory within the focus of attention
- LTM - information stored in the LTM that is inactive but could be retrieved
-
Linking LTM and WM:
- Working memory involves activation of many areas of the brain that involve long term memory, such as the phonological loop using lexical representations stored in the LTM
- Long term WM - a concept from Ericsson and Kintsch (1995) which proposes that the use of semantic and linguistic knowledge can boost memory performance, using LTM structures to boost WM performance
- Multicomponent model - incoming information is processed by systems that are influenced by the LTM, and the working memory provides an interface between cognition and action, which can handle a range of modalities and stages of processing
Neurobiological basis of WM -
- Found association with frontal cortex areas, which when activated have successful recall but when disrupted lead to poorer outcomes
- Complex circuit that undermines the visuo-spatial sketchpad
- Trace decay - phonological loop (loss of information)
- Semantic coding used for long term storage, range of codes in STM
Working memory - generally refers to memory that allows us to manipulate active information and to perform mental arithmetic
- STM - accessible information and can be immediately used - overlap between WM and STM as primary memory
- LTM - recollection of information (secondary information, James 1890)
-