attention and scene perception Flashcards
attention
any of the very large set of selective processes
can be internal or external
can be over or covert
not a single thing
family of mechanisms that restrict bias processings
provides a way to select what to be aware of, what to store in memory, and what information to use in guiding action
selective attention
the form of attention involved when processing is restricted to a subset of the possible stimuli
restricting processing to some stimuli; instead of all ability to pick one or a few out of many stimuli
reaction time
measure of the time it takes from the onset of a stimulus to a response
external
attending to stimuli in the world
internal
attending to one line of though over another or selecting one response over another
overt orienting
directing a sense organ toward a stimulus, like turning your eyes or head
covert orienting
attending without giving an outward sign you are doing so
din’t want someone to know you are directing your attention there
paying attention to something without directing sensory organs toward it
divided
splitting attention between two different stimuli
ie/ driving on the cell phone
sustained
continuously monitoring some stimulus
transient
direct attention for a moment
automatic (reflexive) orienting
unpredictable occurrences automatically capture our attention
- sudden visual onset/offset
- sudden loud noise
- sudden movement
just happens you are not thinking about it
volitional orienting
directing attention due to the goals and intentions of an individual
intend to
teacher directing attention to see if students understand
cue
a stimulus that provides a hint about where the target may appear
exogenous cue
peripheral cue
summon attention automatically by their physical salience
endogenous cue
considered something like instructions that can be voluntarily obeyed
inhibition of return
relative difficulty in getting attention to move back to a recently attended location
posner cueing paradigm
use knowledge or context to generate an expectancy about the stimulus
probe detection
study attentional orienting
what grabs attention earlier peripheral (exogenous) vs symbolic (endogenous) cues
peripheral (exogenous) cues
object-based attention
attention selects particular objects (or perhaps, potions of objects), rather than just a single location
inhibition of return (IOR)
the relative difficulty in getting attention (or the eyes) to move back to a recently attended (or fixated) location
have to overcome inhibition to go back to that location
visual search
looking for a target in a display containing distracting elements
provide a closer approximation of some actions of attention in the real world
ie/ looking for a mug in a cupboard or face in a crowd
some searches are so easy we don’t think of them as searchers ie/ finding the cold-water tap on a sink
set size
the number of items in a visual search display
search efficiency
the average increase in RT for each distractor item added to the display
measured in terms of search slope, or ms/item
the larger the search slope (more ms/item), the less efficient the search
how we can work our way through a diplay
salience
the vividness of a stimulus relative to its neighbour
stands out
target seems to pop out, so it doesn’t matter how many distractors there are
feature search
searching for a target defined by a single attribute, such as a salient colour or orientation
occurs in parrallel
parallel
in visual attention, referring to the same processing of multiple stimuli at the same time
pop out
RT does not change with set size
salience
properties like colour, size and orientation
conjunction search
search for a target defined by the co-occurrence of two or more features
guided
no single feature defined the target
inefficient (between efficient and inefficient)
occurs serially
ie/ apple is red, round and large - eliminating most of the competition
serial self-terminating search
a search from item to item, ending when a target is found or all items have been checked
can be luck (finding target first try) or unlucky (finding target last try)
spend more time with each item
slow
the binding problem
the challenge of
tying different attributes of visual stimuli,
which are handled by different brain
circuits, to the appropriate object so we
perceive a unified object
▪ Example: target(s) are red vertical
bars
▪ Colour, motion, and orientation
are represented by separate
neurons
▪ How do we combine these
features when perceiving the
bar?
feature integration theory
Treisman’s theory of visual
attention, which holds that a limited set of basic features can be processed in parallel preattentively, but that other properties, including the correct binding of features to
objects, require attention
▪ Attention is the glue that binds features together
basic features of colour and orientation are available in a preattentive (processing of a stimulus occurs before selective attention is deployed to that stimulus) stage of processing
illusory conjunction
an erroneous combination of features in a visual scene
▪ Evidence that some features are represented
independently of each other and need to be bound
together
false combination of features from more than one object - based on info we have
attention is the glue for binding to occur
ie/ seeing a red x when the display contained red letters and x’s but no red x
guided search
attention is restricted to a subset of
possible items based on information about the item’s
basic features (e.g., colour or shape)
reduce search
basic features guide visual search - can narrow down search
scene-based guidance
information in our understanding of scenes that helps us find specific objects in scenes
ie/ toilet means you are in the bathroom
anchor objects
typically a relatively bug object that provides info about the location of other objects
ie/ toilet provides info about location of toilet paper
response enhancement
an effect of attention on the response of a neuron responding to an attended stimulus gives a bigger response
sharper tuning
neuron responding to a stimulus more precisely
effect of attention
altered tuning
effect of attention where the neuron responding differently to the features of an attended vs. unattended stimulus
attention changes preference of neurons
rapid serial visual presentation (RSVP)
an experimental procedure in which stimuli appear in a stream at one location (typically the point of fixation) at a rapid rate (typically about ten per second)
▪ used to study the temporal dynamics of visual
attention
▪ Attentional blink: the difficulty in perceiving and
responding to the second of two target stimuli amid a
RSVP stream of distracting stimuli
▪ The second target is often missed if it appears within
200 to 500 ms of the first target
attentional blink
the difficulty in perceiving and responding to the second of two target stimuli amid a RSVP stream of distracting stimuli
▪ The second target is often missed if it appears within 200 to 500 ms of the first target
as if our ability to attend to characters in RSVP is temporarily knocked out, even if our eyes re still open
attentional problem
repetition blindness
the failure to recognize a second
occurrence of a visual display
▪ Occurs when the displays are shown within about
500 milliseconds of each other
priority map
a hypothetical neural representation of visual space in which the activity at each point reflects how much location (or object) will attract attention
lateral interparietal area
a brain region present in both parietal lobes that serves an important role in the control of attention
frontal eye fields
brain region in both frontal lobes that help to coordinate visual selective attention with the movements of the eyes
superior colliculus
a structure int he midbrain that is important in initiating and guiding eye movements
“spotlight” model
attention is restricted in space and
moves from one point to the next. Areas within the
spotlight receive extra processing
attention is like a glue
specific locations or objects are selected for processing that allows for binding and object recognition
flashlight you can shine on it, thing outside aren’t as processed
“zoom lens” model
the attended region can grow or shrink depending on the size of the area to be processed
▪ can vary the locus, extent, and detail set of the
attentional “beam”
we can change the focus
the more focused attention is the more soemthing will be processed
global superiority effect
people noromally focus on global figure
attention as a filter
often focus our attention on a stimulus while excluding others
cocktail party phenomenon
conversing with someone while other people in environment or music - everything in environment is being processed by ears
but we can still filter this to selectively process a conversation
dichotic listening task
how we can we bring the cocktail party phenomenon into a lab
two passages being presented, one to each ear
Broadbent
early selection
Only notice low-level sensory details of unattended
channel
Moray
Discovered that you often notice your own name in
the unattended channel
contradicted broadbent
treisman
message switching - at least temporarily
attenuated filter model
Deutsch and Deutsch
late selection filter - process things first
all information is processed fairly deeply
so we can decide what is important
Corteen and Wood
Initial phase:
▪ Present list of words with some city names
▪ City names were followed by a small shock
Testing phase:
▪ Dichotic listening task
▪ Attended stream: unrelated (non-city) words
▪ Unattended stream: words and city names
▪ Measured galvanic skin response (GSR)
Result: Increased GSR to city names (old and new) in unattended
stream indicating categorical processing of unattended items
Implication: unattended items must have been processed to at least
the categorical level
not low level processing because we have to associated cities with shock - even if its a new city
where is the attention filter
both
Resource theories of attention:
▪ Attention has a pool of resources
▪ Resources are allocated in priority sequence
▪ The more difficult the primary stimulus processing,
the less processing of other stimuli
▪ Automatic vs Controlled processing
▪ With practice, fewer resources are required
▪ Examples: learning to drive, typing, sports
inattentional blindness
a failure to notice a fully-visible,
but unexpected object or event because attention is
focused elsewhere
▪ “looking without seeing”
change blindness
the failure to notice a change
between two scenes
▪ If the change does not alter the gist, or meaning, of
the scene, quite large changes can pass unnoticed
▪ Demonstrates that we do not encode and remember
as much of the world as we might think we do
only take in a small portion of things
gist
primary character of a scene
visual field-defect
a portion of the visual field with no
vision or with abnormal vision, typically resulting from
damage to the visual nervous system
ie/ mud on a windshield
we can not recognize objects or find what we are looking for without attention
unilateral visual neglect
a condition in which a person has difficulty attending to stimuli in one half of the visual field - can’t attend to things
▪ Almost always occurs in the left half of the visual
field
▪ Typically results from damage to the contralateral
posterior parietal cortex (PPC)
▪ Attention, NOT vision, is the issue
behave as if half the world isn’t there
sometimes neglect one side of an object rather than one side of the visual field - object based component
extinction
in visual attention, the inability to perceive a
stimulus to one side of the point of fixation in the presence of another stimulus, typically in the other visual field
related to neglect
will only respond to things on one side
one object can be picked up, even if on the neglected side
frequently in stroke and alzheimers
makes them shave one side of the face, leave haqlf
loss of attention to one side of space
doesn’t think to look to the side they can’t see
not aware of the problem, but people are pointing it out
blindsight
the ability to point to and sometimes
discriminate visual stimuli without any conscious
awareness of them
▪ Damage to V1
can interact with stimuli
opposite of extinction almost
seem to be doing better than they should be
ADHD
One of the most common disorders of attention
▪ Characterized by impulsivity, hyperactivity, inattentiveness
▪ Despite these deficits, some aspects of visual
attention in those individuals with ADHD seems to be
fairly typical (visual search and IOR)
▪ But have difficulty with vigilance tasks, and show
larger ABs
they may perform better in things they enjoy
good for brainstorming - don’t inhibit, more creativity
difference in tasks involving temporal attention have more of an impact
difficulty with day to day activities
