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Selective and Divided Attention

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on 4 August 2015

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Transcript of Selective and Divided Attention

Basic Paradigms for Studying Selective Attention

Cocktail Party Problem
- the process of tracking one conversation in the face of the distraction of other conversations.
- proposed by Colin Cherry

Filter and Bottleneck Theories of Selective Attention

Filter
-blocks some of the of the information going through and selects only a part of the total information to pass through to the next stage.

Bottleneck
-slows down information passing through.
Attentional-Resource Theories of Selective Attention
Attentional-resource theories help to explain how we can perform more than one attention-demanding task at a time. They posit that people have a fixed amount of attention that they can choose to allocate according
to what the task requires.
Additional Considerations in Selective Attention
The Role of Task, Situation, and Person Variables
The Stroop Effect
Divided Attention
Consciousness of Complex Mental Processes
Cognitive Neuroscientific Approaches to Attention and Consciousness
THANK YOU!

Shadowing
-
participant listen to two different messages and is required to repeat back only one of the messages as soon as possible after he/she hear it.

Dichotic Presentation
-different messages to each ear
Binaural Presentation
-the same messages to both ears

Multimode Theory
Multimode theory proposes that attention is flexible. Selection of one message over another message can be made at any of various different points in the course of information processing.
Stage 1
The individual constructs sensory representations of
stimuli.
Stage 2
The individual constructs semantic representations.
Stage 3
The representations of Stages 1 and 2 become conscious.
Neisser's Synthesis
Ulric Neisser synthesized the early-filter and late-filter models and proposed that there are two processes governing attention:
Preattentive Processes
These automatic processes are rapid and occur in parallel. They can be used to notice only physical sensory characteristics of the unattended message. But they do not discern meaning or relationships.
Attentive, Controlled Processes
These processes occur later. They are executed serially and consume time and attentional resources, such as working memory. They also can be used to observe relationships among features. They serve to synthesize fragments into a mental representation of an object.

Moray’s Selective Filter Model
■Moray found that even when participants ignore most other high-level (e.g., semantic) aspects of an unattended message, they frequently still recognize their names in an unattended ear. He suggested that the reason for this effect is that powerful, highly salient messages may break through the filter of selective attention. But other messages may not.

■To modify Broadbent's metaphor, one could say that, according to Moray, the selective filter blocks out most information at the sensory level. But some highly salient, or personally important, messages are so powerful that they burst through the filtering mechanism.
Amount of practice
in performing a given task or set of tasks
Related to this is the skill of utilizing attentional resources for a task or tasks. Increased practice and skill enhance attention.
Stage of processing at which attentional demands are needed
This stage may be before, during, or after some degree of perceptual processing.
Nature of the task
For example, it may be highly difficult, complex, or novel. Such tasks require more attentional resources than do easy, simple, or highly familiar tasks. Task difficulty particularly influences performance during divided attention.
Specific interest in a target task and stimuli, compared with
interest in distracters
Overall arousal
One may be fired, drowsy, or drugged, which may limit

attention. Being excited sometimes enhances it.
John Ridley Stroop
The
Stroop effect
demonstrates the psychological difficulty in selectively attending to the color of the ink and trying to ignore the word that is printed with the ink of that color.

■ One explanation of why the Stroop test may be particularly difficult is that, for most adults, reading is now an automatic process. It is not readily subject to your conscious control. For that reason, you find it difficult intentionally to refrain from reading
and instead to concentrate on identifying the color of the ink, disregarding the word printed in that ink color.
■ An alternative explanation is that the output of a response occurs when the mental pathways for producing the response are activated sufficiently. In the Stroop test, the color word activates a cortical pathway for saying the word. In contrast, the ink-color name activates a pathway for naming the color. But the former pathway interferes with the latter. In this situation, it takes longer to gather sufficient strength of activation to produce the color,naming response and not the word-reading response.
Variations of the Stroop effect
■ number Stroop
■ directional Stroop
■ animal Stroop
■ emotional Stroop


Number Stroop
In the number Stroop, number words are used. Thus, the word
two
might be written three times,
two
,
two
,
two
, and the participants be asked to count the number of words. As with the standard Stroop task, reading sometimes interferes with the counting task
Emotional Stroop
One of the most extensively used Stroop variations is the emotional Stroop. In this task, the standard task is modified so that the color words are replaced with either emotional or neutral words. Participants arc asked to name the colors of the words. Researchers find that there is a longer delay in color naming for emotional words as compared with neutral words. These findings suggest that the automatic reading of emotional words causes more interference than reading of neutral words.
Ulric Neisser
Robert Becklen
Neisser and Becklen hypothesized that improvements in performance would have occurred eventually as a result of practice. They also hypothesized that the performance of multiple tasks was based on skill resulting from practice. They believed it not to be based on special cognitive mechanisms.
A second view is that people's access to their complex mental processes is not very good. In this view. people may think they know how they solve complex problems, but their thoughts arc frequently erroneous. According to Nisbett and Wilson, we typically are conscious of the products of our thinking, but only vaguely conscious, if at all, of the processes of thinking.
The following year, investigators used a dual-task paradigm to study divided attention during the simultaneous performance of two activities. The dual-task paradigm involves two tasks (Task A and Task B) and three conditions (Task A only, Task B only. and both Tasks A and B). The idea was that the researchers would compare and contrast the latency (response time) and accuracy of performance in each of the three conditions.
Change Blindness
The inability to detect changes in objects or scenes that are being viewed.

Change blindness is not limited to visual information. The inability to detect a change can be observed in auditory and tactile stimuli. However, as in visual stimuli, a brief delay must be present between the original and changed stimuli.
One view is that people have quite good access to
their complex mental processes. Simon and his colleagues, for example, have used
protocol analysis
in analyzing people's solving of problems. such as chess problems and so-called cryptarithmetic problems, in which one has to figure out what numbers substitute for letters in a mathematical computation problem. These investigations have suggested to Simon and his colleagues that people have quite good conscious
access to their complex information processes.
These results suggest that people are much less astute in recognizing changes in their environments than we might expect. Even fairly blatant changes, such as the
identity of a person to whom we speak, may pass us by. When we admire Sherlock Holmes for his astuteness, we probably give him too little credit. In the fictional detective stories in which he plays a role, he notices extremely unobvious things. Often we tend not to notice even things that arc obvious.
Attention Deficit Hyperactivity Disorder (ADHD)
First described by Dr. Heinrich Hoffman in 1845.
Three primary characteristics of ADHD
a. inattention
b. hyperactivity (i.e., levels of activity that exceed what ;s normally shown by children of a given age)
c. impulsiveness.
Three main types:
1. predominantly hyperactive-impulsive

2. predominantly inattentive

3. combination of inattentiveness with hyperactivity and impulsiveness.
Children with the inattentive type of ADHD show several distinctive symptoms
1. They are easily distracted by irrelevant sights and sounds.
2. They often fail to pay attention to details.
3. They are susceptible to making careless mi stakes in
their work.
4. They often fail to read instructions completely or carefully.
5. They arc susceptible to forgetting or losing things they need for tasks, such as pencils or books.
6. They tend to jump from one incompleted task to another.
Is attention a function of the entire brain. or is it a function of discrete attention-governing modules in the brain?
Spatial Neglect
Spatial neglect
or just
neglect
is an attentional dysfunction in which participants ignore the half of their visual field that is contralateral, on the opposite side, to the hemisphere of the brain that has a lesion. It is due mainly to unilateral lesions in the parietal lobes. Research reveals that the problem may be a result of the interaction of systems that mutually inhibit one another. When only one of the pair involved in the system is damaged, as is the case with neglect patients, patients become locked in to one side of the visual field. The reason is that the inhibition normally provided by the other half of the system is no longer working.
Attentional Systems
Posner ( 1995) has identified an anterior (frontward) attention system (attentional network) within the frontal lobe and a posterior (toward the rear) attention system within the parietal lobe. The anterior attention system becomes increasingly activated during tasks requiring awareness. An example would be tasks in which participants must atend to the meanings of words.
Using Event-Related Potentials to Measure Attention
An alternative way of studying attention in the brain is to focus on studying event-related potentials. They indicate minute changes in electrical activity in response to various stimuli.
A Psychopharmacological Approach
Evaluates changes in attention and consciousness associated with various chemicals (e.g., neurotransmitters such as acetylcholine or GABA, hormones, and even central nervous system stimulants ["uppers"] or depressants ["downers"]. In addition, researchers study physiological aspects of attentional processes at a global level of analysis.
Studying Divided Attention
One widely used paradigm makes use of a simulation of the driving situation. Researchers had participants perform a tracking task. The participants had control of a joystick, which moved a cursor on a computer screen. The participants needed to keep the cursor in position on a moving target. At various times, the target would flash either green or red. If the color was green, the participants were to ignore the signal. If the color was red, however, the participants were to push a simulated brake. The simulated brake was a button on the joystick.
In one condition, participants did the task singly-that is, by itself. In another condition, participants were involved in a second task. This procedure created a dual-task situation. The participants either listened to a radio broadcast while doing the task or talked on a cell phone to an experimental confederate. Participants talked
roughly half the time and also listened roughly half the time. Two different topics were used to ensure that the results were not due to the topic of conversation.
Spelke and colleagues' experiment
Spelke and her colleagues suggested that these findings
showed that controlled tasks can be automatized so thar they consume fewer attentional resources. Further, two discrete controlled tasks may be automatized to function whether as a unit. These authors were quick to point out that the tasks do not, however, become fully automatic. For one thing, they continue to be intentional and
conscious. For another, they involve relatively high levels of cognitive processing.
Selective
and Divided Attention
An entirely different approach to studying divided attention has focused on extremely simple tasks that require speedy responses. When people try to perform two overlapping speeded tasks, the responses for one or both tasks are almost always slower. When a second task begins soon after the first task has Started, speed of performance usually suffers. The slowing resulting from simultaneous engagement in speeded tasks, as mentioned earlier in the chapter. is the PRP effect.
Posner and Rothbart (2007) completed a review of neuroimaging studies in the area of attention. What at first seemed like an unclear pattern of activation can be effectively organized into areas associated with the three subfunctions of attention. The researchers define these functions as alerting, orienting, and executive attention. The researchers organized the findings to describe each of these functions in terms of the brain areas involved, the neurotransmiters that modulate the changes. and the results of dysfunction within this system.
The second function of attention is orienting. Orienting is defined as the selection of stimuli to attend to. The brain areas involved in the orienting function arc the locus coeruleus, right frontal. and parietal cortex. The modulating neurotransmitter for orienting is norephinephrine. Dysfunction within this system is related to autism.
The final function defined within attention is executive attention. Executive attention includes processes for monitoring and resolving conflicts that arise among internal processes. These processes include thoughts, feelings, and responses. The brain areas involved in this final and highest order of attentional process arc anterior cingulated. lateral ventral, prefrontal. and basal ganglia. The neurotransmitter most involved in the executive attention process is dopamine. Dysfunction within this system is associated with Alzheimer's disease, borderline personality disorder, and schizophrenia.
Alerting is defined as being prepared to attend to some incoming event. Alerting also includes the process of getting to this state of preparedness. The brain areas involved in alerting arc the superior parietal, temporal parietal junction, frontal eye field, and superior colliculus. The neurotransmitter that modulates alerting is acetylcholine. Dysfunction of the alerting system is related to attentional changes as we age and to ADHD.
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