Chapter 6

Question 1

the process of attention

Answer 1

process of focusing on specific objects while ignoring others is the process of attention
The act of at- tending not only brings an object into view; it enhances the pro- cessing of that object and therefore our perception of the object

Question 2

19th century by William James

Answer 2

the first pro- fessor of psychology at Harvard. James relied not on the results of experiments but rather on his own personal observations
to prevent overloading the system and therefore not processing anything well, the visual system, in James’s words, “withdraws from some things in order to deal more effectively with others.

Question 3

One of the mechanisms for selecting certain things in the visual environment for enhanced processing is visual scanning

Answer 3

looking from one place to another. This scanning is necessary because there is only one place on the retina—the cone-rich fovea—that creates good detail vision.

Question 4

two aspects of scanning

Answer 4

Each time you briefly paused on one face you were making a fixation. Fixations provide us with the opportunity to focus on a particular person (or object) so that we can recognize him or her (or it).
When you moved your eyes to observe another face, you made a saccadic eye movement—a rapid jerky movement from one fixation to the next. These eye movements allow us to shift our attention and focus to other people and objects in a scene

Question 5

stats on scanning

Answer 5

when you are freely viewing an object or scene without searching for a target, you move your eyes about three times per second, and more than 200,000 times each day
taly, for only 5 seconds.

Question 6

Overt vs Covert

Answer 6

Scanning involves overt attention—attention that involves looking directly at the attended object. Although we often look directly at the objects of our attention, objects can also be attended even when they are not fixated. Covert attention is attention without looking. Covert attention enables you to monitor the actions of that interesting man or woman sitting near you in class without staring. It is also an important part of many sports
We are constantly shifting our overt and covert attention to monitor what is going on in our environment

Question 7

Visual Salience

Answer 7

Scene regions that are markedly different from their surroundings, whether in color, contrast, movement, or orienta- tion, are said to have visual salience. Visually salient objects can attract attention
You were asked to find a green circle, and the red diamond is neither green nor a circle. Regardless, people attend to the red diamond because it is highly salient, and salient items attract people’s attention
attentional capture

Question 8

Saliency Map

Answer 8

such as color, orientation, and intensity at each location in a scene and combine these values to create a saliency map of the scene. A saliency map reveals which regions are visually different from the rest of the scene
When Parkhurst calculated saliency maps for a number of pictures and then measured observers’ fixations as they observed the pictures, he found that the first few fixations were more likely to occur on high-saliency areas. After the first few fixations, however, scanning begins to be influenced by cog- nitive processes that depend on cognitive factors

Question 9

Cognitive factors

Answer 9

related to an observer’s knowledge, goals, interests, and expectations.

Question 10

Scene Schemas

Answer 10

Attention is influenced by scene schemas—an observer’s knowledge about what is contained in typical scenes
because a printer is less likely to be found in a kitchen. The fact that people look longer at things that seem out of place in a scene means that attention is being affected by their knowledge of what is usually found in the scene.
They found that the subjects were more likely to detect stop signs positioned at intersections than those positioned in the middle of a block, and that 45 percent of the subjects’ fixations occurred close to intersections

Question 11

Observer Interests and Goals

Answer 11

Attention can also be influenced by a person’s goals. In a classic demonstration, Alfred Yarbus (1967) recorded sub- jects’ eye movements while they viewed Ilya Repin’s painting An Unexpected Visitor (Figure 6.7a). The eye movement records in Figure 6.6 b-d show how subjects looked at the picture when told to determine the ages of the people (Figure 6.7b), remember the clothes worn by the people
More recent work has shown that people’s intentions and goals can actually be decoded from their eye movements

Question 12

Task-Related Knowledge

Answer 12

Because most tasks require attention to different places as the task unfolds, it isn’t surprising that the timing of when people look at spe- cific places is determined by the sequence of actions involved in the task.
The per- son rarely fixated on objects or areas that were irrelevant to the task,
“just in time” strategy—eye movements occur just before we need the informa- tion they will provide

Question 13

Benefits of Attention

Answer 13

attention enhances our response to objects (we respond faster to things that are located where we are attending), perception of objects (attention can make it easier to see an object), and physiological responding (attention can enhance the neural response to objects)

Question 14

Attention Speeds Responding

Answer 14

Paying attention informs us about what is happening at a location, and also enables us to respond more rapidly to anything that happens in that location.
Speeding Responding to Locations:
called spatial attention.
Posner and cowork- ers (1978) asked whether paying attention to a location im- proves a person’s ability to respond to stimuli presented there. To answer this question, Posner used the precueing procedure
the general principle behind a precueing experiment is to determine whether presenting a cue indicating where a test stimu- lus will appear enhances the processing of the test stimulus.
Speeding Responding to Objects:
We will now consider some experi- ments that show (1) that attention can enhance our response to objects and (2) that when attention is directed to one part of an object, the enhancing effect of that attention spreads to other parts of the object.

Question 15

Attention Can Influence Appearance

Answer 15

Carrasco’s hypothesis was that attention would cause an increase in the perceived contrast of the gratings.
attended objects are perceived to be bigger, faster, and more richly colored

Question 16

Attention Can Influence Physiological Responding

Answer 16

Attention to Objects Increases Activity in Specific Areas of the Brain
FFA, PPA, and MT/MST
attending to the movement caused activity in the movement areas, MT/MST, for both moving face and moving house stimuli.
Datta and DeYoe created “attention maps” that show how directing attention to a specific area of space activates a specific area of the brain. These attention maps are like the retinotopic map
brain activa- tion is changing not because images are appearing at different places on the retina, but because the subject is directing his or her mind to different places in the visual field.
tention also causes changes in the relationship between activity in different areas of the brain

Question 17

Bosman and coworkers (2012) dem- onstrated this by recording a response called the local field potential (LFP) from the monkey’s cortex.

Answer 17

The effect of attention, it turns out, isn’t on the size of the responses recorded from V1, but on the relationship between the responses recorded from V1 and V4.
osman used a statistical procedure to determine a mea- sure called coherence, which indicates the degree to which two signals are synchronized

Question 18

Why Is Binding Necessary?

Answer 18

cells sensitive to the ball’s shape fire in his IT cortex, cells sensitive to movement fire in his middle temporal cor- tex, and cells sensitive to color fire in other areas. But even though the ball’s shape, movement, and color cause firing in different areas of the person’s cortex, he doesn’t perceive the ball as separated shape, movement, and color percep- tions.
The question of how an object’s individual features become bound together, called the binding problem, is one of the most challenging research questions in perception

Question 19

Feature Integration Theory

Answer 19

Treisman’s theory has proved to be one of the most influential approaches to understanding not just how the binding problem may be solved, but also how visual attention works.
According to FIT, the first step in object processing is the preattentive stage
the preattentive stage oc- curs before we focus attention on an object. Because attention is not involved, researchers argue that this stage is automatic, unconscious, and effortless. In this stage, the features of ob- jects are analyzed independently in separate areas of the brain and are not yet associated with a specific object.
would process the qualities of redness (color), roundness (form), and rightward movement (motion) separately. These independent features are then combined in a second stage of processing, called the focused attention stage
Ie. Scrabble tiles

Question 20

Feature Integration Theory

Answer 20

Treisman’s theory has proved to be one of the most influential approaches to understanding not just how the binding problem may be solved, but also how visual attention works.
According to FIT, the first step in object processing is the preattentive stage
the preattentive stage oc- curs before we focus attention on an object. Because attention is not involved, researchers argue that this stage is automatic, unconscious, and effortless. In this stage, the features of ob- jects are analyzed independently in separate areas of the brain and are not yet associated with a specific object.
would process the qualities of redness (color), roundness (form), and rightward movement (motion) separately. These independent features are then combined in a second stage of processing, called the focused attention stage

Question 21

Illusory conjunctions

Answer 21

These combinations of features from different stimuli are called illusory conjunctions. Illu- sory conjunctions can occur even if the stimuli differ greatly in shape and sizes
Illusory conjunctions also occur outside the world of shapes. For example, when a person sees words like “tooth- paste” and “headache,” they sometimes erroneously remember seeing “toothache.
According to FIT, these illusory conjunctions occur because the divided attention task reduces subjects’ ability to focus their attention on the shapes, and this allows indepen- dent visual features to be combined incorrectly

Question 22

RM

Answer 22

Larger binding failures can be observed in patients with neurological disorders that severely hamper their ability to focus attention
R.M. is a patient who had parietal lobe damage that resulted in a condition called Balint’s syndrome. A crucial characteristic of Balint’s syndrome is an inability to focus and shift attention when multiple objects are present in a scene. According to feature integration theory, an inability to focus attention would make it difficult for R.M. to com- bine features correctly
even when he was able to view the letters for as long as 10 second

Question 23

Visual search

Answer 23

is something we do anytime we look for an object among a number of other objects
Where’s Waldo? picture (Handford, 1997). A type of visual search called a conjunction search has been particularly useful in studying binding.
This is a feature search because you could find the target by looking for a single feature—“horizontal.” Now find the horizontal green line in Figure 6.21b.This is a conjunction search because you had to search for a combination (or conjunction) of two or more features in the same stimulus—“horizontal” and “green.
R.M. can, however, find targets when only a feature search is required, as in Figure 6.21a, because attention at a location is not required for this kind of search.

Question 24

The feature integration ap- proach involves mostly bottom-up processing because knowl- edge is usually not involved.

Answer 24

the subjects’ knowledge of the usual col- ors of objects influenced their ability to correctly combine the features of each object

Question 25

What Happens When We Don’t Attend?

Answer 25

research has shown not only that we miss things that are out of our field of view, but that not attending can cause us to miss things even if we are looking directly at them. One ex- ample of this is a phenomenon called inattentional blindness

Question 26

Inattentional Blindness Change Blindness

Answer 26

This demonstration of inattentional blindness used a rap- idly flashed geometric test stimulus. But similar effects occur for more naturalistic stimuli that are visible for longer periods of time. Daniel Simons and Christopher Chabris (1999), who created a 75-second film that showed two “teams” of three players each. Nearly half of the observers—46 per- cent—failed to report that they saw the woman or the gorilla. Ronald Rensink and coworkers (1997) did a similar experiment in which they presented one picture, followed by a blank field, fol- lowed by the same picture but with an item missing, Rensink found that the pictures had to be alternated back and forth a number of times before the difference was detected. This diffi- culty in detecting changes in scenes is called change blindness 100% of observers failed to detect a one-fourth increase in the size of a building, 92% failed to detect a one-third reduction in a flock of birds, 58% failed to detect a change in a model’s swimsuit from bright pink to bright green, 50% failed to notice that two cowboys had exchanged their heads, and 25% failed to notice a 180-degree rotation of Cinderella’s Castle at Disneyland

Question 27

continuity errors

Answer 27

These changes in films, called continuity errors, have been well documented on the Internet (search for “continuity errors in movies”) One important conclusion that we can draw from dem- onstrations of change blindness is that our experience of a coherent world is sometimes a false reality.

Question 28

Evidence That Perception Can Occur Without Attention

Answer 28

using the dual-task pro- cedure, in which subjects are required to carry out simultane- ously a central task that demands attention and a peripheral task that involves making a decision about the contents of a scene. Li concluded from this result that properties of scenes can be perceived with little or no attention Similar conclusions have been drawn regarding perceiving faces, because people can deter- mine the identity and gender of faces in the near-absence of attention

Question 29

Evidence That Perception Requires Attention

Answer 29

performance dropped to 63 percent when their attention was distracted by the cen- tral letter–number task. From this result, Cohen concluded that “the perception of natural scenes does require attention” Proponents of the idea that perception is possible without attention might note, however, that even though performance on a range of tasks drops when attention is distracted from the scene, it typically remains above chance. Perhaps, then, there are some aspects of scene perception that require attention and some that don’t. that attention is a fun- damental component of perception, even if it might not always be necessary.

Question 30

Distraction and Task Characteristics

Answer 30

Nilli Lavie (1995, 2005, 2010), who showed, in a number of experiments, that if the task is easy, then task-irrelevant stimuli have an effect on performance, but if the task is hard, task-irrelevant stimuli have little or no effect on performance

Question 31

Attention and Perceptual Load

Answer 31

Lavie explains results such as the ones in Figure 6.28b in terms of her load theory of attention, which involves two key concepts: perceptual capacity and perceptual load (Lavie, 2005, 2010). Perceptual capacity refers to the idea that a person has a certain capacity that can be used for carrying out per- ceptual tasks. Perceptual load is the amount of a person’s perceptual capacity needed to carry out a particular percep- tual task. Some tasks, especially easy, well-practiced ones, have low perceptual loads; these low-load tasks use up only a small amount of the person’s perceptual capacity. Lavie proposes that the amount of perceptual capacity that remains as a person is carrying out a task deter- mines how susceptible the person is to being distracted by task-irrelevant stimuli. by a high-load task, such as the hard task in the experiment. When this occurs, no resources remain to process other stimuli, so irrelevant stimuli can’t be processed and they have little effect on performance of the task.

Question 32

Distracted Driving

Answer 32

In 80 percent of the crashes and 67 percent of the near crashes, the driver was inattentive in some way 3 seconds beforehand. . One of the most distract- ing activities was pushing buttons on a cell phone or similar device. More than 22 percent of near crashes involved that kind of distraction Doing this task while talking on a cell phone caused subjects to miss twice as many of the red lights as when they weren’t talking on the phone (Figure 6.30a) and also increased the time it took them to apply the brakes (Figure 6.30b). Perhaps the most important finding of this experiment is that this decrease in performance occurred when subjects used either handheld or hands-free cell phones. There is, in fact, some evidence that having a conversation with a passenger can have an adverse effect on driving, especially if the passenger isn’t paying attention to current driving conditions voice-activated activities to be more distracting, and therefore potentially more dangerous

Question 33

DEVELOPMENTAL DIMENSION:Attention and Perceptual Completion

Answer 33

many attentional processes don’t begin to emerge until after 3 months of age, and the full development of processes such as scanning the details of scenes continues well unto childhood and early adolescence habituation procedure, which is based on the following fact about infant looking behavior: When given a choice between a familiar stimulus and a novel one, an infant is more likely to look at the novel one If the infant can tell the difference between the habituation stimulus and the new stimulus, he or she will exhibit dishabituation—an in- crease in looking time when the stimulus is changed Thus, movement helped the 4-month-old infants infer that the bar extended behind the block Thus, the capacity demonstrated at 4 months does not exist (or can’t be measured using this particular procedure) at birth Apparently, the ability to use movement as a way to orga- nize the perceptual world develops rapidly over the first few months of life Thus, the capacity demonstrated at 4 months does not exist (or can’t be measured using this particular procedure) at birth Apparently, the ability to use movement as a way to orga- nize the perceptual world develops rapidly over the first few months of life Notice that the perceiver fixated mainly on the rod, whereas the nonperceiver fixated on the rectangular occluder. Eye movement records also showed that, as a group, perceiv- ers made more horizontal eye movements than nonperceivers.