Orienting Attention
• Posner Cue - Target Paradigm:
Subject presses a button as soon as x appears
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
X
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
That was a validly cued trial because the x appeared in the box that flashed
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
X
Orienting Attention
• Posner Cue - Target Paradigm:
Orienting Attention
• Posner Cue - Target Paradigm:
That was an invalidly cued trial because the x appeared in the box that didn’t flash
Paradigms Used To Study Attention
• Posner Cue - Target Paradigm:
Attention Effect = Valid RT - Invalid RT
Voluntary Orienting
• Under what circumstances would a cue lead to a voluntary shift of attention?
Voluntary Orienting
• Under what circumstances would a cue lead to a voluntary shift of attention?– Informative cue– Validity = greater than 50%
Voluntary Orienting
• Under what circumstances would a cue lead to a voluntary shift of attention?– Informative cue– Validity = greater than 50%
• What is another way to make this paradigm a voluntary orienting paradigm?
Voluntary Orienting
• What is another way to make this paradigm a voluntary orienting paradigm?
Symbolic cues may orient attention towards another location.Stimulus cues orient attention to the stimulated location.
Symbolic Cue
Voluntary Orienting
• What is the time course of voluntary orienting?
Cue - Target Interval
ResponseTime
Invalidly Cued Targets
Validly Cued Targets
About 200 ms
Reflexive Orienting
• Attention can be automatically “summoned” to a location at which an important event has occurred:
Reflexive Orienting
• Attention can be automatically “summoned” to a location at which an important event has occurred:– Loud noise– Motion– New Object
• We call this attentional capture
Transients
Reflexive Orienting
• The Posner cueing paradigm (with blinking boxes) confounds reflexive and voluntary orienting
… in what way?
Reflexive Orienting
• The Posner cueing paradigm (with blinking boxes) confounds reflexive and voluntary orienting
• How could we change the Posner cueing paradigm to make it asses only reflexive orienting?
Reflexive Orienting
• The Posner cueing paradigm (with blinking boxes) confounds reflexive and voluntary orienting
• How could we change the Posner cueing paradigm to make it asses only reflexive orienting?
• Make validity 50% (non-informative cue)
Reflexive Orienting
• Time course of reflexive orienting is counterintuitive
Cue - Target Interval (ms)
ResponseTime
Valid
Invalid
0 500 1000About 50 ms
Reflexive Orienting
• Time course of reflexive orienting is counterintuitive
• Delayed response at validly cued location after long cue-target interval is known as inhibition of return (IOR)
Reflexive Orienting
• Time course of reflexive orienting is counterintuitive
• Delayed response at validly cued location after long cue-target interval is known as inhibition of return (IOR)
• Thought to occur because attention goes to cued location, then leaves and is inhibited from returning
Reflexive Orienting
• Can symbolic cues be reflexive?
Almost never but …
Reflexive Orienting
• Can symbolic cues be reflexive?
Reflexive orienting to direction of eye gaze
Reflexive Orienting
• Potential cues for Reflexive Orienting– Loud noise– Motion– New Object
• New Objects are powerful attention grabbers!
Transients
New Objects Capture Attention
IS THERE AN “H”?
Initial scene viewed for several hundred ms
Yantis & Jonides (1990): New-Object Paradigm
New Objects Capture Attention
New scene: search for target letter
IS THERE AN “H”?
Yantis & Jonides (1990): New-Object Paradigm
H may be revealed from and 8 or may appear as a new object
Reflexive Orienting
• Steven Yantis and colleagues– Result:
Reflexive Orienting
• Steven Yantis and colleagues– Result:
Targets are found faster when they are “new objects” than when they are revealed from “old” objects
Reflexive Orienting
• Steven Yantis and colleagues– Interpretation:
The visual system prioritizes in dealing with visual objects - relatively recent objects are “flagged” while older objects are disregarded
The Physiology of Attention
Physiology of Attention
• Neural systems involved in orienting
• Neural correlates of selection
Disorders of Orienting
• Lesions to parietal cortex can produce some strange behavioural consequences
ParietalLobe
Disorders of Orienting
• Lesions to parietal cortex can produce some strange behavioural consequences
– patients fail to notice events on the contralesional side
– Patients behave as if they are blind in the contralesional hemifield but they are not blind
Disorders of Orienting
• Lesions to parietal cortex can produce some strange behavioural consequences
– patients fail to notice events on the contralesional side
– Patients behave as if they are blind in the contralesional hemifield but they are not blind
Disorders of Orienting
• Called Hemispatial Neglect - patients appear unable to process information in the contralesional hemifield
Disorders of Orienting
• Hypothesis: Parietal cortex somehow involved in orienting attention into contralesional space
Disorders of Orienting
• Posner and colleagues
– Use cue-target paradigm to investigate attentional abilities of parietal lesion patients
Contralesional Ipsilesional
Disorders of Orienting
Results: Valid cue in contralesional field is effective
invalid- contralesional target
valid - contralesional target
invalid - ispilesional target
valid - ipsilesional target
Results: Severe difficulty with invalidly cued contralesional target
Disorders of Orienting
• Interpretation:– Patients have difficulty disengaging
attention from good hemifield so that it can be shifted to contralesional hemifield
Disorders of Orienting
• Interpretation:
– Patients have difficulty disengaging attention from good hemifield so that it can be shifted to contralesional hemifield
– Parietal cortex is somehow involved in disengaging attention
Disorders of Orienting
• Disengage - Shift - Engage Model– Parietal Cortex notices events and
disengages attention
Disorders of Orienting
• Disengage - Shift - Engage Model– Parietal Cortex notices events and
disengages attention– Superior Colliculus moves attention
Disorders of Orienting
• Disengage - Shift - Engage Model– Parietal Cortex notices events and
disengages attention– Superior Colliculus moves attention– Pulvinar Nucleus reengages attention
Disorders of Orienting
• Disengage - Shift - Engage Model– Parietal Cortex notices events and
disengages attention– Superior Colliculus moves attention– Pulvinar Nucleus reengages attention– Entire process is under some top-down
control from Frontal Cortex
Disorders of Orienting
• Orienting mechanism can be interfered with in normal brains
Disorders of Orienting
• Orienting mechanism can be interfered with in normal brains– changes that are not accompanied by transients are hard to
detect
Disorders of Orienting
• Orienting mechanism can be interfered with in normal brains– changes that are not accompanied by transients are hard to
detect• e.g. building appearing slowly
• orienting mechanism scans the scene aimlessly
Disorders of Orienting
• Orienting mechanism can be interfered with in normal brains– changes that are not accompanied by transients are hard to
detect• e.g. building appearing slowly
• orienting mechanism scans the scene aimlessly
– changes accompanied by full-field transients are hard to detect
• e.g. change blindness
• orienting mechanism is blinded by the transient