lecture 7- attention as a spotlight

Question 1

a filter that leaks doesn’t work the way it should. but a filter that slips is “user error”

Question 2

status of the filter theory

Answer 2

“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!

Question 3

lachter, forster and RuthRuff, 2004

Answer 3

• 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.

Question 4

what are the 4 different things-

Answer 4

• relevant location
• irrelevant location
• repeated prime
• unrelated prime

Question 5

dependant variable

Answer 5

how quickly people can respond to whether it is a word or not

Question 6

where and what is filter?

Answer 6

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.

Question 7

biased competition model (desimone and duncan, 1995)

Answer 7

• 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”

Question 8

review so far..

Answer 8

• 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.

Question 9

what are the 3 models of attention?

Answer 9

• Attention as filter (Broadbent, 1958)
• Attention as spotlight (Posner, 1980)
• Attention as glue (Treisman, 1980)

Question 10

posners ‘spotlight’ model

Answer 10

• 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

Question 11

posner et al., 1980

Answer 11

• 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).

Question 12

exogeneous cueing

Answer 12

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.

Question 13

more on cueing

Answer 13

• 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.

Question 14

cue validity

Answer 14

• 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…

Question 15

cue target interval

Answer 15

• 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…

Question 16

DOES THE CUE “ILLUMINATE”?
OR JUST SPEED UP RESPONSES?

Answer 16

???

Question 17

spatial cues:

Answer 17

• Enhance contrast
• Distort object size
• Saturate colour
• Accelerate motion
• Increase duration
• (among other things!)

Question 18

HOW FAR CAN WE TAKE THE METAPHOR?
(CAVE AND BICHOT, 1999)

Answer 18

• Does it “slide”? No. It jumps.
• Does it “focus”? There can be larger and smaller attended regions and there is evidence it is “brighter” when more tightly focused.
• Is it “brighter” in the middle than at the edges? There is a gradient of attention but this is flexible, see above.
• There’s also a “spotdark”: Regions can be selected for suppression as well as
  enhancement.
• Can you “split the beam”? Usually, no

Question 19

what/where is this spotlight?

Answer 19

• Neurophysiological evidence that spatial cues enhance neural responses (e.g. in V4, Luck et al, 1997)
• Enhancement matches the timecourse of reaction time effects (Bisley and Goldberg, 2003)
• There is a “priority map” in the parietal lobe – peaks of higher activity for prioritised locations (e.g. Bisley & Goldberg, 2010)
• Priorities can be driven by endogenous and exogenous factors

Question 20

current opinion of the spotlight

Answer 20

• Cueing effects are a robust and versatile behavioural marker of spatial shifts of attention
• Important observations about attention have been inspired by the spotlight framework
• It is more of a metaphor than a model (and there’s an obvious homunculus problem with the metaphor).
• There are many features and types of attention to which the spotlight metaphor is not easily applied.