Attention and Consciousness Chapter 3

Attention and Consciousness
Chapter 3
Outline
1. The Nature of Attention and
Consciousness
2. Attention
1.
2.
3.
4.
Vigilance and Signal Detection
Search
Selective Attention
Divided Attention
3. Cognitive Neuroscientific Approaches to
Attention
1.The Nature of Attention and
Consciousness
• Attention
– Is the means by which we actively process a limited
amount of information from the enormous amount of
information available through our senses, our stored
memories, and our other cognitive processes
• Consciousness
– More directly concerned with awareness – it includes
both the feeling of awareness and the content of
awareness, some of which may be under the focus of
attention
1.The Nature of Attention and
Consciousness
Different conceptions of consciousness:
• Biopsychological
– different levels of arousal (sleep, coma, hyperactivity)
• Meta-cognitive
– Reflection on your own cognitive processes
– Being aware of cognitive processes
• Psychoanalytic
– Unconscious information – we do not have access to
it in normal awakened state
• Phenomenological
– What it is like to have an experience of something
– Individual, subjective aspects of experience
1.The Nature of Attention and
Consciousness
Relationship between attention and
consciousness
•
•
•
•
Attention + Consciousness
No attention + No Consciousness
Attention + No Consciousness
No attention + Consciousness
?
Can you provide an example of each of the
possible relationships between attention
and consciousness?
1.The Nature of Attention and
Consciousness
1. Preconscious Processing
•
Information that is available for cognitive
processing but that currently lies outside
of conscious awareness exists at the
preconscious level of awareness
1.The Nature of Attention and
Consciousness
•
1. Preconscious Processing
Priming
– Processing of certain stimuli is facilitated by
prior presentation of the same or similar
stimuli
– Sometimes we are aware of the prime
sometimes we are not
– Even when we are not aware of the prime,
the prime will influence the processing of the
target
1.The Nature of Attention and
Consciousness
1. Preconscious Processing
•
•
•
Antony Marcel (1983)
Participants had to classify series of words into
various categories (e.g. pine-plant)
Primes where words with two meanings such
as palm followed by target word (tree or hand)
Task outline:
Is this a plant?
Prime – PALM
Target - TREE
1.The Nature of Attention and
Consciousness
1. Preconscious Processing
-
-
Antony Marcel (1983) (cont.)
If the participant was consciously aware of
seeing the word “palm”, the mental pathway for
only one meaning was activated
If the word “palm” was presented so briefly that
the person was unaware of seeing the word,
both meanings of the word appeared to be
activated
1.The Nature of Attention and
Consciousness
1. Preconscious Processing
Tip-of-the-tongue phenomenon
•
•
We try to remember something that is known
to be stored in memory but that cannot quite
be retrieved
People who can not come up with the word,
but who thought they knew it, could identify the
first letter, indicate the number of syllables, or
approximate the word’s sounds
1.The Nature of Attention and
Consciousness
1. Preconscious processing
•
•
•
Blindsight
Lesions in some areas of the visual cortex
Patients claim to be blind
When forced to guess about a stimulus in the
“blind” region, they correctly guess locations
and orientations of objects at above-chance
levels
1.The Nature of Attention and
Consciousness
2. Controlled Versus Automatic Processes
• Controlled processes
– Require intentional effort; full conscious
awareness; consume many attentional
resources; performed serially; relatively slow
• Automatic Processes
– Little or no intention or effort; occur outside of
conscious awareness; do not require a lot of
attention, performed by parallel processing;
fast
1.The Nature of Attention and
Consciousness
2. Controlled Versus Automatic Processes
• Many tasks that start off as controlled
processes eventually become automatic
ones
• Automatization
– The process by which a procedure changes
from being highly conscious to being relatively
automatic
?
Can you provide some examples
of automatic and controlled processes?
1.The Nature of Attention and
Consciousness
3. Habituation
• Habituation
– We become accustomed to a stimulus, we gradually
notice it less and less (e.g. music and studying)
• Dishabituation
– A change in a familiar stimulus prompts us to start
noticing the stimulus again
• Sensory adaptation
– Physiological phenomenon; not subject to conscious
control; occurs directly in the sense organ, not in the
brain
2. Attention
1. Vigilance and Signal Detection
• We vigilantly try to detect whether we did or did
not sense a signal (a particular target stimulus of
interest)
• Vigilance
– A person’s ability to attend to a field of stimulation
over a prolonged period, during which the person
seeks to detect the appearance of a particular target
stimulus
– Example – (Mackworth, 1948)
• Participants were watching when a clock hand took a double
step
• Substantial deterioration after half an hour of observation
• Vigilance can be increased with training
2. Attention
2. Search
• Search
– Scan the environment for particular features
– Whereas vigilance involves passively waiting for a
signal stimulus to appear, search involves actively
seeking out the target
• Distracters
– Nontarget stimuli that divert our attention away from
the target stimuli
– Can cause false alarm
2. Attention
2. Search
2 kinds of search:
• Feature search
– When we can look for some distinctive
features of a target we simply scan the
environment for those features (e.g. T vs. O)
• Conjunction search
– We look for a particular combination of
features (e.g. T vs. L, p. 85)
2. Attention
2. Search
• Feature-Integration Theory (Anne Treisman)
– Each of us has mental map for representing the given
set of features for a particular item (shape, size, color
features)
– During feature searches we monitor the relevant
feature map for the presence of any activation in the
visual field
– During conjunction searches, we can simply use the
map of features, we must conjoin two or more
features into an object representation at a particular
location
2. Attention
2. Search
• Similarity theory (Duncan and Humphreys)
– As the similarity between target and distracter
increases, so does the difficulty in detecting
the target stimuli
– Factors influencing search
• Similarity between the target and the distracters
• Similarity among distracters (p. 86, 87)
2. Attention
2. Search
• Guided search theory (Cave and Wolfe)
– All searches involve two consecutive stages
• Parallel stage – simultaneous activation of all the potential
targets
• Serial stage – sequential evaluation of each of the activated
elements
• Movement-Filter theory (McLeod at al.)
– Movement-filter – can direct attention to stimuli with a
common movement characteristics
– Movement can both enhance and inhibit visual search
2. Attention
3. Selective Attention
• Stroop effect (Stroop, 1935)
– Demonstrates the psychological difficulty in
selectively attending to the color of the ink and trying
to ignore the word that is printed with the ink of that
color
– Since reading is an automatic process (not readily
subject to your conscious control) you find it difficult
intentionally to refrain from reading and instead to
concentrate on identifying the color of the ink
2. Attention
3. Selective Attention
• The cocktail party problem (Cherry, 1953)
– The process of tracking one conversation in the face
of the distraction of other conversations
• Shadowing
– Listening to two different messages and repeating
back only one of the messages as soon as possible
after you hear it
• Dichotic presentation
– Listening to two different messages (presenting a
different message to each ear) and attending to only
one of them
2. Attention
3. Selective Attention
Filter and Bottleneck Theories
• Broadbent’s Model
– We filter information right after it is registered at the
sensory level
• Moray’s Selective Filter Model
– The selective filter blocks out most information at the
sensory level, but some highly salient messages are
so powerful that they burst through the filtering
mechanism (e.g. your name)
2. Attention
•
3. Selective Attention
Filter an Bottleneck Theories (cont.)
Treisman’s Attenuation Model
1. We preattentively analyze the physical properties of
a stimulus (stimuli with target properties)
2. We analyze whether a given stimulus has a pattern,
such as speech or music
3. We sequentially evaluate the incoming messages,
assigning appropriate meanings to the selected
stimuli messages
2. Attention
3. Selective Attention
Filter and Bottleneck Theories (cont.)
• Deutsch and Deutsch’s Late Filter Model
– Placed the signal-blocking filter later in the
process, after sensory analysis and also after
some perceptual and conceptual analysis of
input had taken place
• Neisser’s Synthesis
– Two processes governing attention
• Preattentive processes (rapid, automatic, parallel)
• Attentive processes (controlled, occur later, serial)
2. Attention
3. Selective Attention
Attentional-Resource Theories
• We have attentional resources specific to
a given modality
– Explains why we can study and listen to a
music but not listen to news
2. Attention
4. Divided Attention
• The attentional system must perform two
or more discrete tasks at the same time
– much better performance at two or more
automatic tasks (driving a car and speaking)
than controlled tasks (writing and
comprehending read text)
3. Cognitive Neuroscientific
Approaches to Attention
• Hemineglect (Martha Farah)
– Patients ignore half of their visual field
• Attention deficits have been linked to
lesions in
– The frontal lobe
– The basal ganglia
Stroop Effect
Read through this list of color names as
quickly as possible. Read from right to left
across each line
Red
Blue
Yellow
Yellow
Red
Green
Blue
Green
Red
Green
Yellow
Blue
Stroop Effect
Name as quickly as possible the color of ink
in which each word is printed. Name from
left to right across each line.
Red
Yellow
Blue
Blue
Red
Yellow
Green
Blue
Green
Yellow
Green
Red