lecture 7- attention as a spotlight Flashcards
a filter that leaks doesn’t work the way it should. but a filter that slips is “user error”
status of the filter theory
“In psychology, the pace of advance is such that a snapshot of the views of the
present day may seem to have nothing in common with those of a few years ago. This is in truth a sign of strength and of the power of the experimental method; but it can look like frivolity and lack of sound scholarship to those who have not followed the line of thought that has led from one view to another.” - Broadbent, D.E. (1971). Decision and Stress, p. 2.
- Nonetheless… Lachter, Forster & Ruthruff, 2004: Broadbent’s filter theory was essentially right. All evidence that unattended information is remembered has
come from experiments that did not ensure this information was truly
unattended.
This is
important!
lachter, forster and RuthRuff, 2004
- Lexical decision task: is
this string of letters a word or
not? - Repetition priming: faster
responses when the target is
primed with the same
information. - Always attend and report
the letter strings in the
bottom row.
what are the 4 different things-
- relevant location
- irrelevant location
- repeated prime
- unrelated prime
dependant variable
how quickly people can respond to whether it is a word or not
where and what is filter?
Refresher on visual processing through the
hierarchy – assembly of edge/color information from V1, increasingly
complex and increasingly large Receptive Fields (RFs) as you move through visual areas into temporal cortex. [feeding eventually into concept-related areas, which are nonspatial.
biased competition model (desimone and duncan, 1995)
- Stimuli compete to drive cells at multiple
levels/areas. - Large and/or non-spatial receptive fields at
higher levels of representation means only a
select number of things can be represented at
a time => non-selected stimuli are simply not
represented - Competition can be biased to favour
behaviourally relevant perceptual features
(more on this later)
Answer: there is no filter! Attention is “an emergent property of many neural mechanisms working together to
resolve competition for… control of behavior”
review so far..
- Broadbent’s selective filter theory (1958)
- Evidence for and against the idea that attention is required for identification
- Complexities in determining the fate of unattended information
- Supplanting of the filter idea by the competition model of Desimone and Duncan (1995)
- Required reading: Lachter, J., Forster, K.I., & Ruthruff,E. (2004). Forty-five years after Broadbent (1958):Still no identification
without attention. Psychological Review, 111, 880-913. - Recommended reading: Desimone, R., & Duncan, J. (1995).
Neural mechanisms of selective visual attention. Annual Review
of Neuroscience, 18,193–222.
what are the 3 models of attention?
- Attention as filter (Broadbent, 1958)
- Attention as spotlight (Posner, 1980)
- Attention as glue (Treisman, 1980)
posners ‘spotlight’ model
- Michael I. Posner (1936-)
(Emeritus Professor at University of Oregon) - Mainly known for developing
the “Posner Cueing Paradigm” to study attention - Also did pioneering studies in attentional development in children, and in using PET to
localize brain function
posner et al., 1980
- When the target appears where you expect it to, you’re faster to detect it.
- This is specific to location. Expecting a particular letter does not make you faster to
detect that letter. - “These findings are consonant
with the idea of attention as
an internal eye or spotlight.”
(page 171).
exogeneous cueing
Outside the centre of focus
An exogenous cue is presented outside the centre of focus, usually highlighting the left or right box. An exogenous cue can also be an object or image in the periphery, a number of degrees away from the centre, but still within the visual angle. This cue relies on visual input from the peripheral visual field.
more on cueing
- Cues can be endogenous, or exogenous, or both. Combined endo/exo cues have the most powerful effect on detection RT
- Can use a range of different cue types: arrows, numbers, peripheral signals, auditory signals, faces looking left or right…
- Can use a range of different tasks: detection,
discrimination, localization, eye movements,
pointing… - Results tend to be largely the same: faster responses at the cued location, slower at the uncued.
cue validity
- Can modify the probability that the target will be in the same place as the cue
- 75%: cue predicts the target location – strong cueing effects
- 50% un-informative cue – purely “reflexive” cueing effects*
- 25% counter-cueing – reversed cueing effects*
- But this depends on time…
cue target interval
- AKA cue-target “Stimulus Onset Asynchrony” (SOA)
- Allows you to measure the timecourse of
the effect of the cue. - Do cueing effects get larger over time?
Smaller? - Depends on the type of cueing…
