© 2010 by W. W. Norton & Co., Inc. Paying Attention Chapter 4 Lecture Outline.

© 2010 by W. W. Norton & Co., Inc.

Paying Attention

Chapter 4Lecture Outline


Chapter 4: Paying Attention

Lecture OutlineSelective AttentionDivided AttentionPractice


Selective Attention

Selective attention refers to the skill through which one focuses on one input or one task while ignoring other stimuli.


Selective Attention

Attention studies sometimes employ a task known as shadowing.Using headphones, different information is

presented to each ear. This is known as dichotic listening.

The participant pays attention to the information presented to one ear (the attended channel) while ignoring information presented to the other (the unattended channel).


Selective Attention

Results from these studies suggest that unusual characteristics of the unattended channel go unnoticed.

Similar effects happen in visual studies, e.g., in a classic study, participants asked to count the number of basketball passes failed to notice a person in a gorilla suit enter the scene.


Selective Attention

There are some important exceptions, where certain pieces of information will be noticed even if presented to the unattended channel. The participants own name, or any words of high

personal significance, will be noticed even in the unattended channel.

This pattern is observed in real-life situations and sometimes called the cocktail party effect.


Selective Attention

Sometimes effects of attention are so strong that we fail to see stimuli that are directly in front of our eyes.

For instance, if participants are asked to look at a fixation target while attending to another part of the screen, they may fail to notice changes in shape to the fixation target. This phenomenon is known as inattentional blindness.


Selective Attention

A phenomenon similar to inattentional blindness occurs when a distracted person cannot find something in the refrigerator, even if it is directly in front of the eyes.


Selective Attention

From studies of inattentional blindness, one might be tempted to conclude that there is “no perception without attention.”

However, other studies demonstrate that unconscious perception still occurs in the absence of attention.


Selective Attention

For example, participants’ judgments of line length are influenced by the presence of “fins” that cause the Müller-Lyer illusion, even if they do not consciously see the fins.


Selective Attention

Other studies of attention focus on a phenomenon known as change blindness, the inability of observers to detect changes in scenes they are looking directly at.

See if you can detect the differences between the following pairs of pictures:


Selective Attention


Selective Attention

Similar effects of change blindness occur when people fail to notice continuity errors in films.

In a particularly striking example, participants failed to notice when the person asking them for directions changed identity (following a brief interruption by two people carrying a door).


Selective Attention

Early studies of attention focused on when the perceiver selects the desired input.

According to the early-selection hypothesis, the unattended input receives little to no analysis.

According to the late-selection hypothesis, all input receives analysis but only the attended input reaches consciousness or is remembered.


Selective Attention

Both the early- and late-selection hypotheses capture part of the truth.For instance, the study discussed earlier

showing that unattended stimuli have effects on perception seems to be a case of late selection.

However, the electrical activity of the brain for attended versus unattended inputs differs within 70 ms of stimulus presentation, suggesting early selection.


Selective Attention

An experiment by Posner and Snyder (1975) illustrates that there are two kinds of priming related to attention.

One kind of priming is stimulus-based, the other is expectation-based.

For this type of study, the dependent variable is the response time to make a decision about the stimuli.


Selective Attention


Selective Attention

Posner and Snyder (1975) found in the low-validity condition that the primed condition was faster than neutral.This demonstrates an effect of repetition

priming; the receptors were “warmed up.” But, the misled condition was not any

slower than neutral.Warming up the “wrong” detector does not

take activation away from the correct one.


Selective Attention

Posner and Snyder (1975) found in the high-validity condition that the primed condition was much faster than neutral.This demonstrates an additional effect of

expectation in addition to repetition priming. Further, the misled condition was slower

than the neutral condition.Expectation is limited in capacity; the

“wrong” expectation interferes with activating the correct detectors.


Selective Attention

Studies of spatial attention examine the ability to focus on a particular position in space and to be prepared for stimuli appearing in that position.


Selective Attention

For example, when detecting a stimulus on the right or left side of the screen, participants benefit if an arrow provides a cue indicating on which side the stimulus is about to appear (Posner et al., 1980).

Note that directing spatial attention is different than moving the eyes.


Selective Attention

Spatial attention is sometimes thought of as a “searchlight.”

We can move this searchlight in space, as well as adjust the size of the “beam.”


Selective Attention

Do we attend to positions in space or to objects?

Evidence from unilateral neglect syndrome, caused by damage to the right parietal lobe, could be argued to support a space-based view. These individuals cannot attend to the left side of space.

However, some experiments suggest that the deficit is also object-based.


Selective Attention

Unilateral-neglect patients attended to the red circle, initially presented on the right, even after it rotated to the left side of the object.

Healthy participants also show a mixture of spatial and object-based attention.


Selective Attention

Summary of selective attention:Attention involves both facilitating the

processing of desired input and inhibiting the processing of unwanted input.

Attention can be directed to both what the object is as well at where it is in space.

There is some flexibility in when the effects of attention will take place (early or late).

What we think of as attention is not a single process or a particular mechanism.


Divided Attention

Divided attention refers to the skill of performing multiple tasks simultaneously.

This is only possible when the sum of the tasks’ demands is within the “cognitive budget.”

Julius Caesar was praised for his ability to multitask.


Divided Attention

Some cognitive resources are specialized. For instance, verbal and spatial tasks can sometimes

be performed spatially because each draws upon different resources.


Divided Attention

Other cognitive resources are general. For instance, speaking on a cell phone (even with a

hands-free device) interferes with the ability to drive, even though the two tasks are seemingly very different.


Divided Attention

Several task-general cognitive resources have been proposed, such as:A response selector that is required for

selecting and initiating responses, both physical and mental.

A central executive that sets goals and priorities, chooses strategies, and directs the function of many cognitive processes.


Divided Attention

Executive control is strongly connected with working memory.

It is also believed to inhibit automatic or habitual responses when a situation requires a novel response.

Kane et al. (2001) found that individual differences in working memory did not predict the ability to move the eyes towards a cue (the automatic response), but did predict the ability to move the eyes away from a cue (a novel response).


Practice

As a task becomes more practiced, it requires fewer cognitive resources.

As the ability becomes more automatic, executive control and the response selector are needed less and less.


Practice

Why does practice improve performance?Complex tasks – like playing tennis, playing

the piano, or driving a car – can by themselves create problems in divided attention.

With practice, components of the task change from being a controlled process to being an automatic one.


Practice

Controlled tasks are novel and require flexibility in one’s approach.These tasks require attention and cannot be

carried out if the person is busy with another task.

Automatic tasks are well practiced and do not require flexibility.These tasks require little or no attention and

can be carried out if the person is also busy with another task.


Practice

The downside of automaticity is seen in tasks that require the participant to override an automatic response.

The Stroop task illustrates the high automaticity of reading.

Try to name the ink color and do not read the word.


Practice

In this variant of the Stroop task, try to identify how many symbols are present in each row.

This also illustrates the automaticity of reading the numbers.


Practice

Summary of divided attention and practice:Tasks require resources, and you cannot

“spend” more resources than you have.Some resources are task-specific, and others

are task-general. If two tasks make demands upon the same

resources, the result will be interference.Practice increases the automaticity of a task,

resulting in the need for fewer cognitive resources.

© 2010 by W. W. Norton & Co., Inc. Paying Attention Chapter 4 Lecture Outline.

Documents

Transcript of © 2010 by W. W. Norton & Co., Inc. Paying Attention Chapter 4 Lecture Outline.