5 VSTM Flashcards
Name 4 differences between visual sensory storage (iconic memory) & visual short-term memory.
capacity: very large - very small (3-5 items)
duration: 250 ms - some seconds
interference: yes – no
coordinate system: spatial/retinal - spatial/relational
Describe the partial report technique introduced by Sterling.
A grid with 4x3 letters/digits is presented for 50 ms, then interstimulus interval of variable length
then acoustic cue which row the person should recall verbally
Explain why the use of the partial report technique introduced by Sterling does not guarantee the measurement of propertise of the iconic memory alone.
verbal report takes longer than 250 ms
which is longer than the duration of iconic memory
Describe the change detection paradigm typically used in visual short term memory.
A visual field filled with black & white boxes is presented for 1 sec
then a visual inter-stimulus interval (grey screen) variable time
then another field is presented until decision
person has to decide whether the fields are identical
What’s a typical time for the study phase & retention interval in the change detection paradigm typically used in VSTM?
study phase: 1 second
retention interval: > 250 ms, a few seconds max to make sure that it’s not iconic memory anymore
Explain why the use of the change detection paradigm does not guarantee the measurement of properties of the VSTM alone?
If the interstimulus interval is <= 200 ms -> the two stimuli look like one frame and iconic memory could be used
it is generally unknown, where long term memory kicks in
To study VSTM, one has to exclude the contribution of other memory systems. How can we exclude sensory storage?
> 250 ms interstimulus interval
move the stimulus/mask for inference
To study VSTM, one has to exclude the contribution of other memory systems. How can we exclude long-term memory?
unknown
only if fast, other memory systems could potentially be used
To study VSTM, one has to exclude the contribution of other memory systems. Are there any complications?
hard to differentiate
LTM cannot be excluded
Makovski et al. 2010 found differences in two ways to compute d’ (a measure from signal detection theory) in VSTM but not in visual discrimination task, and not in (visual) LTM. Explain how this difference can be used to make sure that in a certain task the contribution of VSTM is at least dominant?
Two methods to compute d’: yes/no task vs. two-alternative forced choice (2AFC) different results for VSTM, not for visual discrimination/LTM-tasks -> only VSTM is sensitive to testing method
-> A certain task (not perceptual discrimination task but have an ISI) -> do a yes/no and 2AFC -> if the task shows variability in d’ based on the testing method, it is likely that VSTM is used
Brandt hypothesized that the differences in signal detection measures found by Makovski et al is due to the fact that, in VSTM, the memory representation dissolves after a single retrieval attempt has been made. To test this hypothesis, we conduct an experiment where we shortly present a visual configuration in the study phase. After a short retention interval (1 second), we test for 2 items successively. If the one-recall hypothesis is true, what result would you expect for both tests in terms of d’ derieved from a yes/no task compared to d’ derieved from a 2AFC task?
d’ would be highest for the yes/no 1st item, then 2AFC 1st item, then the 2nd items
