Cognitive Psychology
Lecture 5: Attention
8th October 2008
James Matthews
Attention
• Today’s Lecture:
• What is Attention
• Focused Auditory Attention
• Perceptual Load Theories
• Focused Visual Attention
• Attentional Systems
• Crossmodal Effects
• Divided Attention & Automatic Processes
What is attention?
• “concentration of mental activity” - Matlin 2005
• “the taking possession of the mind, in clear and vivid form,
of one out of what seem several simultaneously possible
objects or trains of thought. Focalisation, concentration, of
consciousness are of its essence.” - William James 1890
• Mental spotlight
– Focusing
– Ignoring
• Mental Time – Sharing
– Performance of concurrent activities
What is attention?
Traditionally research has distinguished between
two forms of attention:
• Focused attention: Participants are told to attend to one
stimulus and ignore another. This informs us about the
process of selection, and what happens to unattended
stimuli.
• Divided attention: Participants attend to all stimuli. This
informs us about processing limitations and attentional
capacity
What is attention?
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What is attention?
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What is attention?
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What is attention?
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What is attention?
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What is happening up here?
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What is happening up here?
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What is happening up here?
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What is happening up here?
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What is happening up here?
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What is happening up here?
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What is attention?
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Limitations of Research So Far
• Research has so far mainly focused on the external
determinants of attention. Internal factors can be play a
crucial role in attention also.
• In experiments participants are often told what to attend to.
– Is this anything like our real world experience?
• Stimuli are often 2-d, computerised and weird
• Attentional models tend to ignore the influence of
emotional states
– Widely known that anxiety influences attentional processes
Attention in the real world
“If I hadn’t already got a medal, I might have fought a bit
harder. But when you have a medal already, maybe you
think about that medal for a moment. It was probably only
for a lap…but that is all it takes for a race to get away from
you”
Sonia O’ Sullivan, 2000 Olympic Games Silver Medalist
Attention in the real world
“I have learned to cut out all unnecessary thoughts… on the
track. I simply concentrate. I concentrate on the tangible on the track, on the race, on the blocks, on the things I
have to do. The crowds fades away and the other athletes
disappear and now its just me and this one lane”
Michael Johnson
5 time Olympic Gold Medalist
Attention in the real world
“That was the best golf I have ever played. I was in my own
little world, focusing on every shot. I wasn’t thinking what
score I was on or anything…”
Darren Clarke, 1999, having shot
a 60 in the European Open
Focused Auditory Attention
It is possible to hear many conversations, but only listen to
one. We can distinguish the conversation we are interested
in from the rest of the auditory environment by picking up
on a number of features:
• Speaker’s voice
• Speaker’s location
• Content of speech
Focused Auditory Attention
Cherry (1953) and Moray (1959) carried out dichotomous
listening tasks in which participants had to shadow the
speech heard by one ear.
– Listeners seldom noticed if unattended ear contained foreign
language or reversed speech
– Listeners always noticed when speech changed to pure tone
– Listeners seldom remembered content of unattended speech
even if it was a word repeated 35 times
– Unattended ear receives practically no processing
Focused Auditory Attention
Broadbent’s theory:
Reported findings where three digits were presented to
one ear, and a different three were presented to the other.
• Participants chose to recall digits by ear rather than by
pair
Broadbent’s Theory
He accounted for these and other findings in the
following way:
• Two sources on info gain access in parallel to sensory
buffer (this implies the info can linger here)
• One input is allowed through a filter based on its basic
characteristics, while the other remains on the buffer for
later processing
• Beyond the filter a mechanism processes the info
thoroughly (meaning etc.)
Broadbent’s Theory
• Explained experimental findings well
• Assumed wrongly that the unattended message is always
rejected.
– People with practice at shadowing were shown to process up to
67% of unattended info (Underwood, 1974)
• Did not consider presenting inputs in different modalities.
• Wright, Anderson & Stenman (1975) showed processing for
unattended words. They conditioned participants to
associate some words with mild shock.
Broadbent’s Theory
System is inflexible:
Gray & Wedderburn (1960)
Treisman’s Findings
• Reported findings that the unattended words were
sometimes recalled
• Known as ‘breakthrough’
• Occurs when the word in the unattended channel is highly
relevant to the content of the attended input
Treisman’s Theory
Stimulus analysis proceeds through a hierarchy beginning with
physical attributes, and ending with semantic processing.
If there is insufficient processing capacity, then analysis stops
before reaching the end of the hierarchy.
There is a threshold of consciousness that partially processed
stimuli can exceed. So unattended words may
‘breakthrough’
Deutsch & Deutsch (1963) argue that both inputs are
processed fully
Focused Aud. Attention Theories
• All theories propose that somewhere there is a
bottleneck which allows some info through and
slows down the rest.
• The main difference between these theories is the
location of the bottleneck:
• Broadbent argues that bottleneck occurs early in
the system
• Triesman argues that bottleneck occurs mid-way in
the system
• Deutsch & Deutsch argue that bottleneck occurs
late in the system
Perceptual Load Theory
Lavie (2000)
• Everyone has limited attentional capacity
• The amount allocated to main task depends on its
perceptual load (number of units, type of processing)
• Any spare capacity is automatically given to the unattended
input
Perceptual Load Theory
Lavie (2000)
• This leads to the conclusion that there will be an early
bottleneck when perceptual load is high
• And that there will be a late bottleneck when perceptual load
is low
Perceptual Load Theory
Lavie (1995): Participants had to detect either ‘x’ or ‘z’
Low load:
___x_
High load:
artxc
Large distractor letter also appeared. Either a ‘z’ or ‘s’.
The nature of this letter should have a relatively bigger effect
on reaction time in the low load condition
Perceptual Load Theory
The exact nature of ‘perceptual load’ is somewhat vague.
Can we measure it?
Focused Visual Attention
• Studied extensively from a cognitive neuropsychological
perspective.
• Disorders of visual attention:
– Neglect
– Extinction
– Balint’s Syndrome
Neglect
• Results in one half of the visual field being ignored
• The ignored side is contra-lateral to the brain insult
• The person is capable of seeing things to the neglected side
if they shift their head position to bring the item to the other
side of the visual field
Neglect
Results from damage to the right parietal lobe
Neglect
Results from damage to the right parietal lobe
Neglect patients fail to notice or respond to objects presented
on the left side
Extinction
• A single stimulus can be judged normally
• When two stimuli are presented, one goes undetected
• The one that is undetected is on the side contra-lateral to the
brain damage.
x
Extinction
A single stimulus can be judged normally
When two stimuli are presented, one goes undetected
The one that is undetected is on the side contra-lateral to the
brain damage.
x
x
Extinction
“The presence of extinction only during bilateral stimulation is
suggestive of a competative mechanism, whereby the
presence of more salient stimulus presented on the same
side of the spaceas that of the lesion captures attention and
hampers the perception of a less salient stimulus on the
opposite side”
(Marzi et al, 2001)
Balint’s Syndrome
• Results from lesions to posterior parietal lobe, or at the
parieto-occipital junction
• Symptoms:
– fixed gaze
– gross mis-reaching for objects
– simultagnosia (only perceiving one item)
Attentional Systems
• There is often a distinction made between:
• Goal directed attention
– Influenced by expectation, knowledge & current goals
• Stimulus driven attention
– Unexpected occurrences that grab attention
Attentional Systems
There is often a distinction made between
• Goal directed attention
– Dorsal fronto – parietal network
• Stimulus driven attention
– Ventral fronto - parietal
network
Focused Visual Attention
• Location Based Attention:
– It is like a spotlight illuminating an area
– This area can be narrowed if the task demands it
• Object Based Attention:
– Attention is directed to objects rather than to an area
Location Based Attention
Posner (1980) discussed covert attention. Attention can shift
in the absence of eye movements.
Participants fixated on central point and had to identify a light to
the left or right.
Central point could be a neutral cross, or a direction arrow



Location Based Attention
• Posner (1980):
• Valid arrows reduced reaction times from control (cross)
• Deceptive arrows increased reaction times from control
• These happened in the absence of eye movements
Location Based Attention
• St James (1986)
• Participants had to answer about a target stimulus who’s
location was indicated beforehand
• A distractor caused interference
• The area over which interference effects were found was
less when the participants had longer forewarning of the
target stimulus
• Evidence that visual attention zoomed in
Location Based Attention (Limitations)
• Evidence that attention can be split between two nonadjacent regions of space (see Awh and Pashler, 2000)
• Attention can be directed to objects as opposed to areas
Object Based Attention
• O’Craven et al. (1999)
• Two objects appeared superimposed onto each other (face &
house)
• One moved slightly and participants had to attend to either moving
or stationary objects
• fMRI scan showed that face area ‘lit up’ when face was being
attended to and house area ‘lit up’ when house was being
attended to.
• Face area = Fusiform face area
• House area = Parahippocampal place area
Object Based Attention
• Marshall & Halligan (1994) Neglect Patient Study
• Ambiguous shape was seen as either black object with white
background
or
• White object with black background
• They could draw the separating line when asked to draw the
left side of the picture, but not when asked to draw the right
(neglected) side.
• Seen as evidence of object based attention
• Other evidence from plant drawings
Object Based Attention
• It is clear that object based attention is present in humans,
but this view fails to explain the findings that show location
based attention.
• Are the studies ecologically valid???
Crossmodal Effects
• In our everyday negotiation of the world we use cues from
one sensory modality to direct the attention of the other
• Crossing a road: Our ears are drawn by the sound of a car
and this then directs our visual attention
• In the laboratory, Driver & Spence (1998) used tactile
stimulation to improve visual judgement. The tactile cues
drew covert visual attention as the person’s eyes remained
fixated on the central cross
Crossmodal Effects
A more spectacular example!
Crossmodal Effects
The ventriloquist effect happens when we perceive a sound
as coming from the most obvious visual source. It is also
know as visual capture
Crossmodal Effects
• Visual capture usually occurs when there is incongruity
between vision and audition. We are predominantly visual
creatures.
• This normally has to do with location. (Think of the cinema)
• Auditory capture can happen. This normally occurs in
relation to temporal features.
• If a light flashes at one rate and a sound beeps at another,
we perceive the light to be flashing at the auditory rate
Divided Attention
Divided Attention
• Easy for some things:
– Driving and talking
• Hard for other things:
– Patting head and rubbing stomach
Factors effecting dual task performance
• Task similarity:
• Easy to do things which are dissimilar (drive & talk).
• We recall unattended pictures when shadowing an auditory
stream.
• If we have to do different things with items in the same
modality it is difficult
Factors effecting dual task performance
• Practice:
• Spelke et al. (1976) trained people to read and understand
short passages, while writing down words from dictation.
• The performance of participants improved hugely over 6
weeks of training
• “People’s ability to develop skills in specialised situations is
so great that it may never be possible to define general limits
on cognitive capacity”
• Expertise:
– Beilock et al (2002) – Experts utilise less attentional resources
Factors effecting dual task performance
• Task Difficulty:
• Easier to drive and chat, than drive and conduct a job
interview
• This is obvious, but how do we define task difficulty
Automatic Processing
The practice effects shown in Spelke et al. (1976) prompted
speculation as to how we can become so good at difficult
tasks
The common explanation is that some processing becomes
automatic.
Automatic Processing
• Automatic processes do not tax attention:
– They are fast
– They do not reduce capacity for performing other tasks
– They are unavailable to consciousness
– They can be unavoidable
Automatic Processing
The Stroop Effect
Automatic Processing
Attention
Today’s Lecture:
• What is Attention
• Focused Auditory Attention
• Perceptual Load Theories
• Focused Visual Attention
• Attentional Systems
• Crossmodal Effects
• Divided Attention & Automatic Processes
Reading
Eysenck & Keane: Chapter 5
Matlin: Chapter 2