PSYB65 - Chapter 11 - Nov 15, 2010
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Chapter 11: Attention and Consciousness
- Two basic features of attention:
1. Selection of sensory information form several simultaneously available inputs
Selective attention – process that allows the selection of inputs, thoughts, or actions
while other ones are ignored.
Inputs can be sensory; attention can be directed to internal mental processes
2. Selection of mental state, allowing either an internal or external flow of information
Voluntary attention – intentionally shifts attention from one input to another OR
Reflexive attention – shifts occurs in response to some external event
-Even without eye movements, and without changes of accommodation, one can concentrate
attention on the sensation from a particular part of our peripheral nervous system and at the
same time exclude attention from all other parts.
-Cocktail party effect – ability to focus one’s listening attention on a single speaker among a
cacophony of conversations and background noises.
EARLY VS. LATE SELECTION
-Early selection – attention to an input and the decision to further encode and analyze it (e.g.
categorizing and naming) occurs very early in the perceptual process.
Stimulus does not need to be completely encoded or perceived prior to selection or
rejection from further processing.
One possible mechanism: the accommodation or adjustment of sensory organs
E.g. some animals clearly orient their sensory organs when they shift attention, e.g.
shifting position/orientation of ears. However, covert changes that are relatively “low” or
“early” in our sensory systems.
Inner ear function is vulnerable to higher perceptual and attentional processes.
-Late selection – attention operates after the sensory information has been perceived,
identified, and/or categorized.
Stroop effect, where people are presented colour word with different colour inks
slower to name the colour of the print
This effect can happen only if the word is recognized at a semantic level, despite the fact
that the individuals were told not to read the word.
HOW DOES ATTENTION SHIFT?: VOLUNTARY VS. REFLEXIVE ORIENTING
-Attention can be overt (e.g. moving eyes when shifting visual attention), or covert (e.g. in
Helmholtz’s experiment, visual attention didn’t correspond to the location of visual fixation)
Voluntary Shifts in Attention
-Changes that you intentionally initiate, changing the focus of your attention from one thing to
-Attention experiment – people learn to use cue to help anticipate the location of target
reduction in their average reaction time (benefit in this paradigm); invalid cues increase
average reaction time (cost)
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Participants cannot directly look at the cued point, although they pay more attention to it
Reflexive Shifts in Attention
-A shift in attention that occurs in response to some external events.
-Involuntary shifts in attention are not always useful or adaptive.
-Exogenous cueing – reaction times to targets can be influenced by the time between the
presentation of the cue and the presentation of the target.
Produces costs and benefits, but both effects are possible for valid cues, depending on
Inhibitory aftereffect (inhibition of return) – cost associated with a cue that occurs more
than 300 milliseconds before the presentation of the target.
-Two leading possibilities of cause:
1. Reflexive orienting responses are normally very short (200> milliseconds). Much longer
durations could potentially result in life-threatening situation.
E.g. you are distracted by your passenger suddenly sneezed while you are driving a
car. Your car could drift into opposite traffic.
2. Cues tend not to provide valid information
NEURAL SYSTEM(S) SUBSERVING ATTENTION
-Practically every cortical cell (exception of some primary visual and motor areas) can have its
activity influenced by attention. Attention is not strictly controlled by cortical structures.
-Baddeley’s model of working memory
(1) Primary component (or central executive) – controlling attention and supervising the
two “slave” subsystems.
(2+3) Two “slave” subsystems – Phonological loop and visuospatial sketchpad –
separate and responsible for manipulating different types of information.
Central executive is involved with the allocation of attention, strategy selection, and the
integration of information received from the two slave systems.
Tasks that are demanding of central executive activation of dorsolateral prefrontal
-Three functionally and anatomically distinct attentional systems are involved in visual
1. Posterior attentional system (PAS)
Involved in orienting spatial attention, including object search and inspection of
the object once it is found.
Main inputs of the PAS: Dorsal (e.g. “how” and “where?”) visual pathway
2. Anterior attentional system (AAS)
Responsible for both the working memory and the executive control system that
subserves the conscious control of attention
Involved in memory, semantics, and control of motor behaviour
Main areas: Cingulate gyrus and frontal cortex
3. Vigilance system (VS)
Prepare and sustain alertness toward signals that demand high priority
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