Topic 6: Visual Attention

Question 1

Attention

Answer 1

the process of focusing on some objects while ignoring others

attention can enhance the processing of the attended object

Question 2

Overt Attention

Answer 2

attention that involves looking directly at the attended object

Question 3

Covert Attention

Answer 3

attention without looking

seeing something “out of the corner of your eye” is an example of covert attention

Question 4

Dichotic Learning

Answer 4

attention experiment technique involving hearing where dichotic refers to presenting different stimuli to the left and right ears

Question 5

Selective Attention

Answer 5

occurs when a person selectively focuses attention on a specific location or stimulus property

Question 6

Shadowing

Answer 6

listener’s repetition aloud of what they hear as they are hearing it

Question 7

Cocktail Party Effect

Answer 7

the ability to focus on one stimulus while filtering out other stimulus, so called because at noisy parties people are able to focus on what one person is saying even though there are many conversations happening at the same time

Question 8

Spatial Attention

Answer 8

attention to a specific location

Question 9

Precueing

Answer 9

a procedure in which a cue stimulus is presented to direct an observer’s attention to a specific location where a test stimulus is likely to be presented

this procedure was used by Posner to show that attention enhances the processing of a stimulus presented at the cued location

Question 10

Illusory Conjunction

Answer 10

illusory combination of features that are perceived when stimuli containing a number of features are presented briefly and under conditions in which focused attention is difficult

for example, presenting a red square and a blue triangle could potentially create the perception of a red triangle

Question 11

Feature Integration Theory (FIT)

Answer 11

a theory proposed by Anne Treisman to explain how an object is broken down into features and how these features are recombined to result in a perception of the object

Question 12

Pre-attentive Stage

Answer 12

an automatic and rapid stage of processing, proposed by Treisman’s feature integration theory, during which a stimulus is decomposed into individual features

Question 13

Focused Attention Stage

Answer 13

the stage of processing in feature integration theory in which the features are combined

according to Treisman, this stage requires focused attention

Question 14

Binding

Answer 14

the process by which features such as colour, form, motion, and location are combined to create our perception of a coherent object

binding can also occur across senses, as when sound and vision are associated with the same object

Question 15

Visual Search

Answer 15

a procedure in which a person’s task is to find a particular element in a display that contains a number of elements

Question 16

Feature Search

Answer 16

a visual search task in which a person can find a target by searching for only one feature

an example would be looking for a horizontal green line among vertical green lines

Question 17

Conjunction Search

Answer 17

a visual search task in which it is necessary to search for a combination (or conjunction) of two or more features on the same stimulus to find the target

an example of a conjunction search would be looking for a horizontal green line among vertical green lines and horizontal red lines

Question 18

Fixation

Answer 18

the brief pause of the eye that occurs between eye movements as a person scans a scene

Question 19

Saccadic Eye Movement

Answer 19

rapid eye movement between fixations that occurs when scanning a scene

Question 20

Corollary Discharge Theory

Answer 20

the theory that explains motion perception as being determined both by movement of the image on the retina and by signals that indicate movement of the eyes

Question 21

Motor Signal (MS)

Answer 21

in corollary discharge theory, the signal that is sent to the eye muscles when the observer moves or tries to move his or her eyes

Question 22

Corollary Discharge Signal (CDS)

Answer 22

a copy of the motor signal that is sent to the eye muscles to cause movement of the eye

the copy is sent to the hypothetical comporator of corollary discharge theory

Question 23

Image Displacement Signal (IDS)

Answer 23

in corollary discharge theory, the signal that occurs when an image moves across the visual receptors

Question 24

Comparator

Answer 24

a structure hypothesized by the corollary discharge theory of movement perception

the corollary discharge signal meet at the comparator to determine whether movement will be perceived

Question 25

Predictive Remapping of Attention

Answer 25

process in which attention begins shifting toward a target just before the eye begins moving toward it, enabling the perceiver to experience a stable, coherent scene

Question 26

Visual Salience

Answer 26

characteristics such as bright colours, high contrast, and highly visible orientations that cause stimuli to stand out and therefore attract attention

Question 27

Attentional Capture

Answer 27

occurs when stimulus salience causes an involuntary shift of attention for example, attention can be captured by movement

Question 28

Saliency Map

Answer 28

a "map" of a visual display that takes into account characteristics of the display such as colour, contrast, and orientation that are associated with capturing attention

Question 29

Same-Object Advantage

Answer 29

the faster responding that occurs when enhancement spreads within an object faster reaction times occur when a target is located within the object that is receiving the subject's attention, even if the subject is looking at another place within the object

Question 30

Perceived Contrast

Answer 30

the perceived difference in the appearance of light and dark bars

Question 31

Inattentional Blindness

Answer 31

a situation in which a stimulus that is not attended is not perceived, even though the person is looking directly at it

Question 32

Change Blindness

Answer 32

difficulty in detecting differences between two visual stimuli that are presented one after another, often with a short blank stimulus interposed between them also occurs when part of a stimulus is changed very slowly

Question 33

Continuity Errors

Answer 33

mismatch, usually involving spatial position or objects, that occurs from one film shot to another

Question 34

Operant Conditioning

Answer 34

a type of learning in which behavior is controlled by rewards, called reinforcements, that follow behaviors

Question 35

Spatial Neglect

Answer 35

neurological condition in which patients with damage to one hemisphere of the brain to not attend to the opposite side of their visual world

Question 36

Extinction

Answer 36

a condition associated with brain damage in which there is a lack of awareness of what is happening in one side of the visual field

Question 37

Pre-attentive Processing

Answer 37

hidden processing that happens within a fraction of a second, below one's level of awareness

Question 38

Meditation

Answer 38

a practice that originated in Buddhist and Hindu cultures, which involves different ways of engaging the mind

Question 39

Focused Attention Meditation

Answer 39

common form of meditation in which a person focuses on a specific object, which can be the breath, a sound, a mantra, or a visual stimulus

Question 40

Mind Wandering

Answer 40

non-task-oriented mental activity also called daydreaming

Question 41

Experience Sampling

Answer 41

technique used to measure the thoughts, feelings, and behaviors of people at various random points in time during the day the technique has been used to measure the frequency of mind-wandering

Question 42

Head-Mounted Eye Tracking

Answer 42

eye tracking technique in which the perceiver is fitted with two devices: a head-mounted scene camera, which indicates the orientation of the perceiver's head and their general field of view, and an eye camera, which indicates the precise location where the person is looking within that field of view

Question 43

What is attention?

Answer 43

mental processes for seeking out and focusing on relevant (visual) stimuli, which are consequently processed to a greater extent (at the expense of other stimuli)

Question 44

Why is the amount of information processed in vision limited?

Answer 44

sensory systems are limited (e.g. visual fixations, size of foveal gaze) motor systems are limited (e.g. movements planned/words spoken sequentially)

Question 45

What are saccades?

Answer 45

small, rapid eye movements

Question 46

What is saccadic suppression?

Answer 46

attenuation in some spatial frequencies during saccade neither motion of the eye/motion blur nor gap in perception is detected begins before eye movement (thus, is not an optical effect)

Question 47

What are fixations?

Answer 47

pauses that typically indicate where a person is attending about 3 fixations/second

Question 48

What determines fixation locations?

Answer 48

visual salience: color, contrast, orientation (bottom-up process) picture meaning/observer knowledge: what do you expect to see? (top-down processing) task demands: what are you being asked to do?

Question 49

What is overt attention?

Answer 49

directing foveal gaze (and attention) to a stimulus

Question 50

What is covert attention?

Answer 50

directing attention to a stimulus in peripheral vision

Question 51

What was the Helmholtz (1896) study on covert attention?

Answer 51

put matrix of letters on wall, with fixation cross in the centre fixated on cross and turned light off directed his attention (not his eyes) to a certain location, then briefly illuminated room with a spark could perceive letters in attended region, but not in other regions attention can be used to select stimuli independent of fixation

Question 52

What is a selective attention task?

Answer 52

requires responding to a stimulus while ignoring others e.g. reading a textbook while trying to ignore interruptions

Question 53

What is a divided attention task?

Answer 53

requires attending to two or more simultaneous stimuli e.g. driving, drinking a coffee, and talking on cell phone at the same

Question 54

What did Michael Posner, Nissen, & Ogden (1978) believe where the components of attention?

Answer 54

attention viewed as a spotlight: can focus on certain locations 1. disengaging attention from current location 2. moving attention to new location 3. engaging attention in new location

Question 55

What conclusions did Michael Posner, Nissen, & Ogden (1978) come to after their study?

Answer 55

reaction time affected by type of cue attention can be directed to a particular location, which enhances perceptual processing if cue is invalid, attention must be disengaged, moved, and re-engaged attention is not only exogenous or "stimulus-driven" (bottom-up), but also endogenous or "goal-directed"

Question 56

What does Balient's syndrome have to do with attention being object-based?

Answer 56

patients experience more illusory conjunctions; deficit in locating targets in conjunction search

Question 57

What does simultanagnosia have to do with attention being object-based?

Answer 57

difficulty in attending to more than object at a time -- even when overlapping supports the idea that attention can be object based syndrome may be due to inability to shift attention among objects

Question 58

What is unilateral neglect?

Answer 58

deficit in awareness of items on one side of space, due to brain damage damage results in neglect of objects (or parts of objects) in the contralesional visual field patients often unaware of this deficit typically due to damage in right posterior parietal cortex, critical to attention and selection

Question 59

What are the explanations for unilateral neglect?

Answer 59

problem in disengaging attention from ipsilateral (same) side; cueing (directing attention) helped reduce spatial biases disruption of balance between hemispheres in directing attention; more stimuli on ipsilateral side hampers attention to contralateral (opposite side) items however, syndrome may be object-based: left side of object neglected, rather than the left side of space patient with object neglect cannot detect differences on the left side of an object -- even when it falls into the right visual field

Question 60

What is egocentric neglect?

Answer 60

unaware of one side of space 11 people overlooked complete apples on the left side of the page; 2 people missed complete apples on the right side brain damage was clustered in right anterior cortical regions, and subcortical structures

Question 61

What is allocentric neglect?

Answer 61

unaware of one side of objects 8 people crossed out apples with gaps on their left side; 2 people crossed out apples with gaps on their right side brain damage was in right posterior cortical regions

Question 62

What are the implications of the existence of both egocentric and allocentric neglect?

Answer 62

these different forms of neglect may reveal the nature of attentional processing attention may be either location-based or object-based different parts of the brain process different kinds of attention damage to location-based system produces egocentric neglect, damage to object-based system produces allocentric neglect location-based processing is better suited to static scenes, whereas object-based processing works well for following a moving object in dynamic scenes

Question 63

What is inattentional blindness?

Answer 63

stimulus that is presented, but is not attended, is not perceived a.k.a. "looked-but-didn't-see" problem

Question 64

What is change blindness?

Answer 64

an inability to detect changes in an object or a scene

Question 65

What are the implications of inattentional and change blindness?

Answer 65

not everything presented to our senses is processed attention is limited visual encoding must be selective or "sparse"

Question 66

What is the binding problem?

Answer 66

how are the independent, parallel subsystems in vision (form, motion, color, etc.) fused together into a unitary percept how are the parts of an object unified into a whole?

Question 67

What is the convergence solution to the binding problem?

Answer 67

Hubel & Wiesel (1977) neurons coding for different aspects of an object (e.g. color, form, etc.) converge on a single neuron detecting that particular combination implies we have a neuron for every object we can recognize ("grandmother cell" theory) problems: little evidence, we can recognize too many objects, cannot account for perception of novel objects

Question 68

What is the temporal synchrony solution to the binding problem?

Answer 68

neurons that signal different aspects of the same object fire in synchrony synchronization does not occur if each assembly is triggered by a different stimulus objects symbolized by synchronized population coding attention may help synchronize neural firing

Question 69

What is feature integration theory?

Answer 69

developed by Anne Treisman attention must be focused on particular stimulus attributes or parts in space to construct a representation or percept

Question 70

What is the preattentive stage of feature integration theory?

Answer 70

rapid, automatic decomposition of stimulus into a number of basic properties ("primitives") processing is in parallel

Question 71

What is the focused attention stage of feature integration theory?

Answer 71

serial process spatial location selected primitives existing at this spot are combined (e.g. redness and X-ness combined into red X-ness) combination object is called object file only exists temporarily to be examined by focused attention

Question 72

What is a visual search task?

Answer 72

primitives determined via visual search experiments task: find target among nontargets/"distractors" observers asked whether a display contain target RT (and errors) are recorded

Question 73

What is a feature search task?

Answer 73

target defined by one basic property/primitive e.g. find a green 2 among red 2s

Question 74

What is a conjunction search task?

Answer 74

target defined by a combination of two or more basic properties/primitives e.g. find a green 5 among green and red 2s, and red 5s

Question 75

What is a spatial configuration search?

Answer 75

target defined by organization of features e.g. find a 5 among 2s

Question 76

What is a pop-out?

Answer 76

time needed to find the target is very short/constant lots of slow, serial processing not required RT not influenced by the number of distractors primitives cause pop-out in feature search: e.g. color, brightness, orientation, length, curvature, etc.

Question 77

What are the pros of visual search tasks?

Answer 77

evidence: illusory conjunctions; when attention is overtaxed, primitives may be incorrectly combined e.g. red Xs, blue Os: you may perceive a blue X e.g. Stroop effect (1935): shows attention inhibition of automatic cognitive processes

Question 78

What are the cons of visual search tasks?

Answer 78

with practice, conjunction search may become automatic/parallel at attention necessary for perception? how can we be aware of anything that we are not attending to? how can we shift our attention to a new stimulus, if we aren't aware that is exists yet? cases of brain damage (e.g., blindsight) can reveal perception without awareness