Lecture 5 - Object-Based Attention, Cognitive Neuropsych Of Attention

Front 1

What does attention act upon?

Back 1

- Spotlight theory

- Feature integration theory (FIT)

assumes attention acts on a region of space

- enhancing processing in that region

ALTERNATIVE

- attention acts on OBJECTS in space, not space itself (Object based theories)

Front 2

Rock and Gutman (1981)

Back 2

- overlapping figures (rate appeal)

- good memory for attended figure

*The objects occupy the same region of space!*

Front 3

What happens to the unattended shape?

e.g name colour of kite, not trumpet

Back 3

- not perceived/not fully perceived?

- - quickly forget? - inattentional amnesia

Front 4

Negative priming

Back 4

RT is slower if ignored on previous trial

(regular priming speeds up RT)

- this means the ignored shape must have been perceived to produce effect on subsequent trial

> LATE SELECTION

Front 5

Rock & Guttman ~ Negative priming implies....

Back 5

it is possible to attend to one object and ignore the other when both occupy same region of space

Front 6

Duncan (1984)

Back 6

Gap in boxes

(4 differing attributes)

flashed, name 2

Results:

More accurate if 2 attributes belong to the same object (Features of box OR features of line)

Front 7

Cueing Object-based Attention (1994)

Back 7

Same object advantage - Mean RT's faster to miscued stimuli if in same object

Cued effects~Cued objects

Front 8

Occluding bar

Back 8

continuous objects (still find object advantage)

Front 9

Neuroimaging Evidence for Object-Based attention

Back 9

Attend to face or house

Face = activates FFA

House = activates PPA

Front 10

Evidence that attention selects objects (in space)

Back 10

* enhancing representation of selected object, suppression of other

*attention to part of an object benefits other parts of the same object

Front 11

Control of attention involves...

Back 11

balance of top-down and bottom-up systems

Front 12

Reflexive system ...

Back 12

orients to new stimuli

Front 13

Voluntary system

Back 13

provides sustained attentional focus

Front 14

Visual neglect is...

Back 14

failure to focus, disengage and reorient

Front 15

Visual neglect is caused by..

Back 15

damage to right parietal lobe

Front 16

Visual pathways

Back 16

- Ventral

- Dorsal

Front 17

Ventral pathway (temporal lobe)

Back 17

WHAT = form/colour

Front 18

Dorsal pathway (parietal lobe)

Back 18

WHERE = Direction of motion, spatial location

Front 19

Visual neglect is caused by

Back 19

stroke, bleeding into brain tissue, causing visual neglect on left side

Front 20

Visual neglect is not problem of vision/perception because...

Back 20

it is an attentional problem, because attentional shift is still possible

Front 21

Cuing deficits (Right parietal damage)

Back 21

Posner:

- compare intact and damaged hemispheres

(patient as own control)

- ability to voluntarily engage attention is not impaired

- difficulty in disengaging and shifting in response to new info

Front 22

what is Extinction?

Back 22

- a symptom of Neglect

- two stimuli - object on right suppresses the one on left

Front 23

Why does extinction occur?

Back 23

damaged hemisphere underactive

- stimuli don't provide activation of neural structure

Front 24

Neglect is stronger when...

Back 24

there is more activity in the other working hemisphere

Front 25

Balint's syndrome

Back 25

- bilateral lesions in parietal and/or occipital cortex

- inability to see more than one fixated object

(even if they overlap)

OBJECT-BASED

Front 26

Attention is mainly associated with which pathway?

Back 26

where (parietal)

Front 27

Spotlight = movement of attention through space... neglect is associated with which side of space?

Back 27

left

Front 28

object tagging

Back 28

attention keeps track of moving objects

- assigning tags to objects

(ignore/pay attention)

Front 29

Inhibition of return

Back 29

interaction of top-down bottom/up systems

- cued location tagged as uninteresting, so slower RT to that spot

Front 30

Standard Inhibition of Return (IOR)

Back 30

Standard IOR:

- peripheral cue

- wait long SOA

- flash target

- slower RT at cued location

Front 31

Object-based IOR

Back 31

flashed peripheral cue, then rotate display

- IOR tracks cued marker to new location

- IOR follows the cued object, not confined to one region of space

* thus proof for object-based

Front 32

Object-based Neglect

Back 32

barbell stimulus

combine two location markers into ONE object

= longer detection RT on left

When rotated 180 deg, longer RTs on the RIGHT!!!!

= neglect tracks marker to opposite visual field

= neglect of left side of objects, not just space

* allows speace/object-based effects to be distinguished

Front 33

Do we know everything about attention?

Back 33

no.

* important interplay between theory and experiments