Lec 3: Attention - Structural And Capacity Theories

Front 1

Cost of divided attention

Back 1

conditions:

-Selective= attend one side, ignore the other

- Exclusive/OR = target could be left or right, but never at same time

* task is harder when you divide attention than when you focus attention to one side

Front 2

Simultaneous (Inclusive/OR condition)

Back 2

need to monitor both channels =

even larger cost (only 31% correct)

Front 3

Implications of Moray study

Back 3

not consistent with either early or late selection theories

Front 4

Structural and Capacity Theories (70s)

Back 4

how performance limitations can occur

Front 5

Structural theories (bottleneck)

Back 5

Some neural structures can only deal with one stimulus at a time

>

competition produces a processing 'bottleneck' (filter theory)

Front 6

Capacity theories (capacity)

Back 6

Information processing is hard work &

processing requires activation of that neural structure

* limited capacity to activate the structure

Front 7

Capacity Theory (Kahneman, 1973)

Back 7

flexibility of allocation of resources/capacity

Front 8

Divided attention example (interference)

Back 8

phone whilst driving = delays reaction time, miss more red lights

Front 9

Attention Operating Characeristic (AOC)

Back 9

dual task paradigm

>

progressive performance changes with change in capacity allocation

'graceful degradation'

*but don't know where the tradeoff curve goes

Front 10

Bonnel & Hafter (1998)

Back 10

Discrimination v. Detection

-compare capacity demands

Front 11

Discrimination (understand meaning)

Back 11

tradeoff - imply limited capacity

Front 12

Detection (preattentive)

Back 12

no trade-off needed = no capacity limit

Front 13

Capacity theory - pros/cons

Back 13

+ led to new experiments

+emphasises divided attention, flexibility of attentional control

- vague - can always explain using capacity

Front 14

Signal Detection Theory

Back 14

(an alternative approach)

How we make decisions about weak/difficult stimuli

- mental representations of stimuli are statistically variable/noisy

- attending to multiple stimuli increases noise and reduces accuracy

- Makes mathematically precise predictions about divided attention costs

-capacity limitations due to varying amount of noise

Front 15

Attentional Orienting (1980s)

Back 15

Attentional shifts precede eye movements, can occur without eye movement ('covert attention')

Front 16

Spotlight of attention (Posner)

Back 16

Shifting attention like a moving spotlight

(for enhanced processing)

- selective, limited capacity

Front 17

Spatial cuing paradigm (Posner)

Back 17

Cue_Stimulus__response

Valid cue = faster response time (benefit)

Invalid cue = slower RT (cost)

*Flexible: can be used with RT or accuracy, compare diff stimuli

Front 18

Interpretation of Cueing Effects

Back 18

Shifts of attention/spotlight

Costs in terms of time (like filter theory)

- takes time to disengage from wrong location

- benefit from engaging at correct location before presented stimulus

but...

Capacity theory would say:

RT depends on capacity allocated to that location

- Neutral = capacity shared

- Focused = uneven capacity allocation

Front 19

Attentional orienting in natural environments

Back 19

Shifts in attention can be topdown (decide to shift)

or bottom up (something captures your attention)

* We need both systems to function for focusing/disengaging

Front 20

2 systems for engaging diff cues

Central/peripheral

Back 20

endogenous = voluntary cues, central, symbolic (cognitive)

exogenous = reflexive, direct, spatial

Front 21

Peripheral cueing effect

Back 21

- peaks faster, transient

Front 22

Central cueing effect

Back 22

- peaks slowly, sustained

( cognitive processing requires capacity)

Front 23

Inhibition of Return

Back 23

= hard to get attention back to a location where a cue was presented if nothing is presented shortly after

found only with peripheral cues, not central

Front 24

What is the purpose of inhibition of return?

Back 24

- ecological view: allows efficient search of complex environment

- prevents repeated search of same locaiton

( no need to maintain mental map of location that has already been searched)

Front 25

Attentional Orienting studies

- evidence for 2 systems

Back 25

Effects of SOA and cue type (reflexive v voluntary)

Affected diff by load - voluntary system is under more cognitive control

Reflexive shows inhibition of return

~reflxive controlled by diff processes

Front 26

Attentional orienting

Back 26

Combination of bottom-up/top-down control

need to be able focus attention, exclude irrelevant stimuli, respond to unexpected threats