Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
Chapter Attention and Consciousness
“Millions of items … are present to my senses which never properly enter into my experience. Why?
Because they have no interest for me. My experience is what I agree to attend to … each of us literally
chooses, by his ways of attending to things, what sort of a universe he shall appear to himself to inhabit”
William James, 1890, Principles of Psychology
Attention is often thought of as a spotlight, aiming to
select some part of the world for conscious access
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
Chapter Outline
1.0 Introduction
2.0 A distinction between attention and consciousness
3.0 Experiments on attention
4.0 The brain basis of attention
5.0 The brain basis of conscious experience
6.0 A summary, and some hypotheses
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
1.0 Introduction
Attention is often thought of as a spotlight,
aiming to select some part of the world for
conscious access.
The ‘spotlight’ of attention is often thought to
involve frontal and parietal cortex, as well as
subcortical regions
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
2.0 A distinction between attention and consciousness
A common sense distinction between attention and consciousness:
We can ask someone to ‘please pay attention’ but not to ‘please be
conscious’. In general, however, when people pay attention to something,
they generally become conscious of it.
The common sense distinction between attention and consciousness
suggests that there are attentional control mechanisms that often
determine what will or will not become conscious …
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
2.0 A distinction between attention and consciousness
Cortical selection and integration
Executive selective attention
processes ‘select’ different
sensory and cognitive
processes, as if the yellow
arrow can ‘point’ to any part
of the diagram.
Conscious cognition is often
the result of attentional
selection.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
2.0 A distinction between attention and consciousness
Cortical selection and integration
An attentional ‘spotlight’ selects among
competing inputs. Cortex can be seen as a
large array of processing hierarchies for
sensory, motor, and cognitive tasks.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
2.0 A distinction between attention and consciousness
Selective attention: voluntary and automatic
Attention can be voluntarily
directed to something in our
environment. This process is
typically referred to as a ‘topdown’ process since the brain
is voluntarily selecting the
sensory information to be
processed.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
2.0 A distinction between attention and consciousness
Another type of attention is
automatic: called ‘attentional
capture’, it happens when
something in our environment
(like a loud noise) captures our
attention without our conscious
attention or voluntary control.
Attentional capture is a ‘bottomup’ process: the sensory input
drives the attentional
processing.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
2.0 A distinction between attention and consciousness
Selective attention: voluntary and automatic
In the real world, voluntary and automatic
attention are generally mixed. For example, we
can train ourselves to pay attention to the new
ringtone we found for our cell phone.
When it rings and we suddenly pay attention to
it, is that voluntary or automatic?
Visual areas involved in active and passive
viewing extend to the parietal lobe
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
3.0 Experiments on attention
Methods for studying selective attention
Early studies of selective attention were
done by Broadbent (1957) and Cherry
(1953): they studied the way we can
selectively listen to competing stimuli.
Cherry coined the term ‘the cocktail
party effect’ to describe how selective
attentional processes are at work in a
busy listening environment.
Selective listening: competing speech streams
are sent to each ear and the subject’s task is
to repeat what they hear as they hear it, called
shadowing. Subjects can repeat only one
stream at a time.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
3.0 Experiments on attention
Methods for studying selective attention
The flanker task is an important tool for studying visual attention. The basic method is
to present a fixation point (+) to the subject, and then present stimuli that ‘flank’ the
fixation point, just outside the foveal region of maximum visual resolution. This task
does not allow eye movements, but relies on covert shifts of visual attention.
The flanker task
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
3.0 Experiments on attention
Methods for studying selective attention: attentional search paradigms
Stimulus-driven attention: ‘pop-out’ vs. effortful search
A well-known case of stimulus-driven attention comes from Anne Treisman’s visual
search paradigm. When a target stimulus differs sharply from the surrounding stimuli,
it tends to ‘pop-out’.
Task: locate the
vertical red bar
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
3.0 Experiments on attention
Methods for studying selective attention: attentional search paradigms
Stimulus-driven attention: ‘pop-out’ vs. effortful search
When the target stimulus shares features (in a conjunction search), more voluntary
effort is required to locate it.
Task: locate the
vertical red bar
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
4.0 The brain basis of attention
Higher neuronal firing to an attended stimulus
A classic example of an attentional increase in sensitivity at the level of a single
neuron. The flower is the preferred stimulus. This neuron (in visual cortex IT, an
object recognition area) begins firing in anticipation of the preferred stimulus at a
higher level than for the non-preferred stimulus.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
4.0 The brain basis of attention
Guiding the spotlight
If we think of attention as a spotlight, we must
also ask the question what is guiding it. Brain
areas like the prefrontal cortex are suggested
as sources of control for voluntary attention,
and the result is improved efficiency in the
visual cortex.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
4.0 The brain basis of attention
Salience maps help guide attentional selection
What determines what object
the attentional system selects?
Ultimately, attention cannot be
understood without taking into
account emotion, motivation,
and salience.
Biologically significant stimuli draw attention: here a single
cell recording shows that a monkey’s THREAT face draws
more attention than a neutral face
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
4.0 The brain basis of attention
Executive (voluntary) attention
Voluntary attention sometimes needs to go
against our existing tendencies: for
example, ignoring a ringing cell phone while
speaking to a friend. The expected behavior
is to answer the phone and executive
attention processes are required to override
that behavior.
The flanker task has been used to
investigate brain networks that are recruited
for executive attention in this type of
situation.
In the flanker task, the subject is cued
to expect a flanker stimulus on the left.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
4.0 The brain basis of attention
Executive (voluntary) attention
In this version of the flanker task, the task is to
covertly (without moving the eyes) attend to
the side of the screen that is cued.
In some trials, a stimulus appears on the cued
side of the fixation point while on others a
stimulus appears on the un-cued side.
On these trials, the subject must override the
tendency to attend to the stimulus on the uncued side and instead use executive attention
to covertly attend to the cued side.
Top: the stimulus appears on the left.
Bottom: the stimulus unexpectedly
appears on the right.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
4.0 The brain basis of attention
Executive (voluntary) attention
Interestingly, the brain networks for maintaining executive attention to the cued side,
overriding the tendency to attend to the side that contains a stimulus, differ from the
networks that guide visual attention to an expected stimulus.
Brain regions that are involved in executive attention in the flanker task include
prefrontal cortex and parietal regions.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
5.0 The brain basis of conscious experience
Conscious cognition
Attention is a selective capacity, an ability to
focus on one thing and not another.
Conscious cognition is closely related but
not identical to attention.
We are usually conscious of the results of
attentional selection, but not necessarily of
selection itself.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
5.0 The brain basis of conscious experience
Unconscious comparisons
How can we investigate conscious
experience?
Consciousness has been used a a variable,
with experiments designed to compare
conscious and unconscious conditions in the
same experiment using the same stimuli.
Backward masking is used to compare
conscious and unconscious perception.
Subjects do not perceive the smiling
face, but the unconscious face still
primes behavior and brain activity
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
5.0 The brain basis of conscious experience
Inattentional blindness
We are often unaware of visual events that occur at the very center of visual
gaze. The most famous example of inattentional blindness comes from Daniel
Simons’ invisible gorilla movie. When subjects are instructed to track the
basketball being thrown back and forth amongst the students, they cannot
‘see’ the person in the gorilla costume walking across the scene.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
5.0 The brain basis of conscious experience
Binding features into conscious objects
The concept of feature binding -combining color, location, shape,
and the like into a single neuronal
assembly -- is often to be necessary
for visual consciousness. Treisman
suggested that an attentional
spotlight was required to combine
different aspects of a stimulus into a
reportable event.
Treisman’s spotlight for binding visual features
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
5.0 The brain basis of conscious experience
Conscious events recruit widespread brain activation
There are many sources of evidence suggesting that
the more we are conscious of some event, from
visual perception to motor control, the more cortical
activity we are likely to find.
Results of an fMRI experiment: brain activation during
a sensorimotor task where subjects were asked to tap
along with the sound of a metronome. Once trained
on the task, the scientists varied the pace of the
metronome by 3, 7, or 20%. Cortical activity
increased dramatically as a function of the
unpredictability of the tapping task.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
5.0 The brain basis of conscious experience
Fast cortical interactions may be needed for conscious events
Recent technical advances have made it possible to record the interactivity of
brain regions. Results of an experiment using visual flicker to evoke widespread
brain synchrony: a flickering stimulus evokes correlated synchronous firing
between active brain regions during conscious perception.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
5.0 The brain basis of conscious experience
Fast cortical interactions may be needed for conscious events
It is believed that rhythmic synchrony between different brain regions may signal
cooperative and competitive interactions between neuronal populations needed to
perform tasks, particularly those that are conscious and under voluntary control.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
6.0 A summary and some hypotheses
Selective attention to a visual stimulus seems to be guided by parts of the
frontal and parietal lobes
Conscious cognition can be shown to recruit frontoparietal regions
Thus selective attention can be thought of as an act of focusing brain resources
on visual cortex -- particularly the region where feature binding seems to take
place.
Conscious cognition can be seen as going in the opposite direction, a visual
object serving to mobilize cortical regions far beyond visual cortex alone.
Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience
Edited by Bernard J. Baars and Nicole M. Gage
2007 Academic Press
6.0 A summary and some hypotheses
Selective attention can be thought of
as an act of focusing brain resources
on visual cortex -- particularly the
region where feature binding seems
to take place.
Conscious cognition can be seen as
going in the opposite direction, a visual
object serving to mobilize cortical
regions far beyond visual cortex alone.