Sensation And Perception Ch. 8 Study Questions

Front 1

Describe the idea behind the cueing paradigm.

Back 1

This paradigm measures how fast a subject responds to a target appearing in one of two boxes under various cueing conditions in order to infer how attention might affect performance. Generally, there is a "valid cue," an "invalid cue" and a "neutral cue." A valid cue refers to a cue signaling the correct information about the target while an invalid cue refers to a cue signaling incorrect information about the target. A neutral cue is uninformative. The idea is that when an invalid cue is given, the observer will take longer to respond to the target than when a valid cue is given. A neutral cue will result in a response that's slower than that of a valid cue case but quicker than that of an invalid cue case. This demonstrates that response to a target depends on prior attention to information in the visual field.

Front 2

What is the "Spotlight" theory of attention?

Back 2

It is based on the idea that attention can be moved from spot to spot in a manner similar to that of a spotlight beam.

Front 3

How are visual search experiments useful for studying attention?

Back 3

Visual search experiments provide a closer approximation to the actions of attention in the real world. The typical visual search experiment requires the observer to find a "target" item among some "distractor" items. This kind of search occurs regularly in the real world. For instance, looking for faces in a crowd, books on a shelf, etc.

Front 4

Explain how a search can be inefficient.

Back 4

When the target and distractors in a visual search task contain the same basic features, the search is inefficient. For example, if all the distractors in the task contain the color blue, and the target also contains the color blue, a search can be inefficient in that the observer may have to go through each item in the display in order to locate the target. This is contrasted with a situation in which the target stands out from the distractors, and as a result the observer does not need to attend to each stimulus in the display.

Front 5

Describe one type of visual search that is efficient.

Back 5

Feature search is an example of an efficient kind of visual search. In this case, the search for a target is defined by a single attribute, such as a salient color or orientation. For instance, imagine having to search for a red car in a parking lot full of white cars. The defining feature (the color red) is sufficiently salient, and it does not matter how many cars are in the parking lot. The red car stands out in the display. In this situation, we process the colors of all of the cars at once, or in parallel, making the search efficient.

Front 6

What is limited-capacity process and how is it related to visual attention?

Back 6

Limited-capacity process is a process that is capable of handling many stimuli at once but that processes each item more slowly as the number of items increases. When confronted with a visual search task, the observer can attend to several items at once, but the more items there are in the display, the longer the observer will take to identify the target stimulus.

Front 7

Why is conjunction search less efficient than feature search?

Back 7

Conjunction search is less efficient than feature search because conjunction search requires searching for a target defined by the presence of two or more attributes (e.g., a blue, horizontal target among green vertical distractors), as opposed to feature search, which only requires searching for a target defined by a single attribute.

Front 8

Describe Treisman's feature integration theory.

Back 8

This theory of visual attention states 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.

Front 9

What is the binding problem?

Back 9

The binding problem is the challenge of tying different attributes of visual stimuli (e.g., color, orientation, motion), which are handled by different brain circuits, to the appropriate object so that we perceive a unified object (e.g., red, vertical, moving right).

Front 10

How is illusory conjunction a by-product of conjunction search?

Back 10

Illusory conjunction is an erroneous combination of two features in a visual scene. For instance, seeing a red X when the display contains red letters and Xes, but no red Xes. This error can occur during a recognition task that involves conjunction search, when the observer tries to report which objects were present in a display of items. The observer confuses attributes of one object with attributes of another.

Front 11

What are the two stages of the feature integration theory?

Back 11

The two stages of the feature integration theory are: 1) preattentive stage, which refers to the processing of a stimulus that occurs before selective attention is deployed to that stimulus. 2) attentive stage, which refers to the processing that requires the deployment of attention to a stimulus or location.

Front 12

Describe one phenomenon where timing is critical to visual attention.

Back 12

One such phenomenon is known as the "attentional blink." In this case, there is a difficulty in perceiving and responding to the second of two target stimuli amid a rapid stream of distracting stimuli if the observer has responded to the first target stimulus within 200 to 500 ms before the second stimulus is present.

Front 13

What is attentional selection, and why is it important?

Back 13

Attentional selection is the ability to attend to specific properties of a display, which may require switching attention from previous properties without moving the eyes. This ability is important because it allows one to focus on the relevant information in a display rather than "getting lost" in the entire display. During attentional selection, different aspects of the display appear more prominent as one shifts attention to the property selected.

Front 14

What do fMRI studies involving the fusiform face area demonstrate about attention?

Back 14

These studies show that attentional selection can be used to perform one type of specialized processing rather than another. One study showed that the fusiform face area is especially important in the processing of faces and that the parahippocampal place area is especially important in the processing of places. If observers view an image of a face superimposed over an image of a house, the face area becomes more active when the observer is attending to the face, and the place area becomes more active when the observer is attending to the house.

Front 15

How is response enhancement related to attentional processing on the cellular level?

Back 15

Response enhancement of single cells is one of the ways in which attention could change the response of a cell. For instance, a cell that responds to a specific orientation (e.g., vertical) might give a stronger response in the presence of attention.

Front 16

Describe sharper tuning and its relevance to attentional processing.

Back 16

Sharper tuning is one possible effect of attention on the response of neurons. Attention might cause a neuron to respond more precisely. For instance, a neuron that responds to lines with orientations from -20° to +20° might come to respond to ±10° lines.

Front 17

What is neglect?

Back 17

Neglect is a disorder of visual attention, in which there is an inability to attend to or respond to stimuli in the contralesional visual field (typically the left visual field after a right parietal damage). Neglect can also involve half of the body or half of an object. The disorder seems to stem from an attentional processing problem rather than from a visual problem: the visual system seems to remain intact.

Front 18

How is extinction related to neglect?

Back 18

Extinction might be neglect in a milder form. Extinction is the inability to perceive a stimulus in the presence of another stimulus, typically in a comparable position in the other visual field. Neglect is a more severe disorder, in which the entire contralesional field might be affected.

Front 19

Describe the symptoms a Balint Syndrome patient might experience.

Back 19

A Balint Syndrome patient usually experiences three symptoms: 1) A hard time trying to reach an object 2) A tendency to gaze fixedly ahead 3) The inability to perceive more than one object at a time

Front 20

Explain how the Flicker paradigm helps to examine the phenomenon of "change blindness."

Back 20

During the Flicker paradigm, observers are given a picture memory experiment. First, they see a picture of a scene, then it vanishes for a split of a second, and then it is replaced by a similar image. The task is to determine what had changed between the two images. The two images continue to flip back and forth (with the blank screen continuing to appear between them) until observer spots the change, or time runs out. The results of this task show that observers are slow at detecting changes, as opposed to a condition where the images flip back and forth without a blank screen appearing between them, where they are much faster. This failure to notice a change between two scenes is referred to as "change blindness."

Front 21

What is the difference between a covert and an overt attentional shift?

Back 21

A covert attentional shift is a shift of attention in the absence of corresponding movements of the eyes. An overt attentional shift is a shift of attention accompanied by corresponding movements of the eyes. Each type of shift helps in the process of attending to objects/scenes.

Front 22

Explain why in Dan Simon's "Gorillas in the Midst" experiment the observers failed to notice the gorilla appearing in the middle of the scene.

Back 22

This failure to notice the gorilla appearing in the middle of the scene was due to the attention of the observers to the task at hand, which was to count how many times the ball was passed from person to person. The observers' prevailing understanding of the scene was so powerful that the gorilla was blocked from entering conscious awareness.