6. Basic Memory Systems: Short-Term Flashcards
modal model of memory
- multiple sensory registers (auditory, visual, haptic)
- short term store for rehearsal
- long-term store that associates information
- model has been shown to be problematic, but it’s simplicity helps communicate basic findings of memory research
modal model of memory: flow chart
env. sitmulus
sensory memory
STM
LTM
refer to notebook page 34
sensory memory (vision)
has bee postulated to have (traditionally) iconic memory (infinite memory)
1. large capacity
2. short duration (250ms)
3. non-interpretable representations (rapid decay)
memory is a reconstruction
visual persistence
- “after images” = straightforward way to understand sensory memory for visual info
- neurons continue to be active AFTER events have ceased to occur in outside world
- continued activation = memory
full-report paradigm
- if sensory info is only available for a brief period, how can we measure it? make it about sensation, but not perception
- found that nb of recalled letters (immediate memory span) is constant for each participant
- qty of info initially acquired cannot be asses because the nb of letters presented exceeds capacity of immediate memory span
What is the benefit of having less Qs on a test, regarding STM
when we increase the nb of Qs, we increase the task difficulty by creating more inteference
partial report paradigm
goal: to determine if participants can register more info than they can recall using the full report procedure
- found that once experimental error has been considered, the results sow that all the briefly presented material is initially registered in memory
- thus, iconic memory has large info storage capacity
What does the partial report paradigm suggest when we are looking at an image briefly
suggests that EVERYTHING is encoded briefly, because we don’t know which row we will be asked to recall
duration of iconic memory
- in a follow up experiment, Sperling used a partial report paradigm
- refer to slides 21-25
- info remains in iconic memory for about 250ms
- pattern of activation becomes desynchronized
issues with the partial report
- if we have access to categorical info, what might we predict would happen with recall performance
- if performance in categorical partial report is better than full report, then iconinc mental representations are interpreted
- if performance in catgeorial partial report is the same as full report, then inconic mental representations are NOT interpreted
categorical partial report
refer to slides 28-29
role of uncertainty
- full report = easier than partial report
- refer to small diagram on page 35 of notebook
delayed recall paradigm
- refer to slides 31-32
- when task difficult is equated across conditions, categorical partial report is better than full report
- some categorical info appears to be available
iconic memory conclusions
- empirical phenomenon = robust
- visible persistence is not informational persistence
- no evidence for a unitary sensory register
- visual persistence might reflect enduring stimulus-related activity in the visual cortex
working memory characteristics
- short term limited store that maintains info until it is required or decays
- capacity is estimated at 4 items
- refer to diagram on page 35 of notebook
specialized buffers
retain info acquired from modalities
levels of activation in LTM items
- all items in lTM have a resting activation, those items in STM are just more active
- items in attention are the most active
central executive
- can only hold 1 item at a time
- coordinates info within subsystems (all have limited capacity and represent info temporarily)
- focus, division and switching of attention
- LTM utilization
central executive and phonological loop evidence example
AFDCB(AEBB)DACB
AFDCBA(EBBD)ACB
STM: modal buffers
- phonological loop (PL)
- modality - audition
- uses lanugae and phonological info - visuospatial sketchpad (VSS)
- modality - vision
- uses visual representations and imagery - episodic buffer
- modality - integration through association of modal information
- used to move info both to and from episodic LTM
refer to notebook page 36 for evidence for these concepts
STM model: modern approach
- later additions to working memory model proposed noth active and passive components
- inner scribe (VSS) andinner speech (PL) actively manipulate info
- this info = stored in passive units of phonological store and visual cache
- refer to diagram on page 36 of notebook
STM model: neurological evidence
- frontal lobes have been singled out as having particularly important role in working memory
- also , dlPFC plays integral role in monitoring and controlling alternative course of action
NOTE: relationship between this model and the motion of controlled and automatic processes
role of LTM
- acts as permanent store
- practically unlimited capacity
- associations with items in working memory enhances storage capacity
item and order info
generally, there is a robust distinction between intem and order info in short term recall tasks
- e.g. I know that I brought the milk in the firdge, but I can’t remember when I bought it
item info
- concerns association one has with external stimulus to other items in memory
- perceptual info: what does it look/sound like
- freq info: how often does this occur in the environment
