Human Cognitive Processes: psyc 345

Ch. 4: Attention

Takashi Yamauchi© Takashi Yamauchi (Dept. of Psychology, Texas A&M University)

Questions

• (Q1) How does attention work?

• (Q2) Under what conditions can we pay attention to more than one thing at a time?

• (Q3) How are attention and visual perception related?

Attention and Autism

• Impaired social interaction and communication– Often fail to understand what other people think.

• Far more autistic boys than autistic girls (4:1)• Overrepresented in children whose parents / grand

parents are engineers – (Baron-Cohen et al.; Autism, 1997, 1, 153-163)

• substantial genetic component

• Video clip

– Invisible wall– Autism and symptoms (3:56)

• http://www.youtube.com/watch?v=FuWWie1DlJY

Attention and Autism

Eye movement: normal (white markers) vs. autistic viewers (black markers)

“neuroenhancing drugs”

• http://www.newyorker.com/reporting/2009/04/27/090427fa_fact_talbot

• A young man I’ll call Alex recently graduated from Harvard. As a history major, Alex wrote about a dozen papers a semester. He also ran a student organization, for which he often worked more than forty hours a week; when he wasn’t on the job, he had classes. Weeknights were devoted to all the schoolwork that he couldn’t finish during the day, and weekend nights were spent drinking with friends and going to dance parties. “Trite as it sounds,” he told me, it seemed important to “maybe appreciate my own youth.” Since, in essence, this life was impossible, Alex began taking Adderall to make it possible.

Adderall, a stimulant composed of mixed amphetamine salts, is commonly prescribed for children and adults who have been given a diagnosis of attention-deficit hyperactivity disorder. But in recent years Adderall and Ritalin, another stimulant, have been adopted as cognitive enhancers: drugs that high-functioning, overcommitted people take to become higher-functioning and more overcommitted.

During his college years, Alex took fifteen milligrams of Adderall most evenings, usually after dinner, guaranteeing that he would maintain intense focus while losing “any ability to sleep for approximately eight to ten hours.”

Attention

• Video demonstration

• Change blindness– http://viscog.beckman.illinois.edu/flashmovie/

12.php– http://viscog.beckman.illinois.edu/flashmovie/

10.php

Attention• Process of concentrating on specific

features of the environment, or on certain thoughts or activities– Excluding other features of the

environment

Mechanism of attention

• (Q1) How does attention work?

• Show me your models.

• Selective attention

• Divided attention (e.g., multi-tasking)

• Visual attention

Selective Attention

• How does it happen?

• How do you characterize the mechanism of selective attention?

– What would be a good metaphor to describe selective attention?

Selective Attention

• Ability to focus on one message and ignore all others– Research method: dichotic listening

• One message is presented to the left ear and another to the right ear

• Participant “shadows” one message to ensure he is attending to that message

In the shadowing procedure, a person repeats out loud words they have just heard.

But they are required to shadow only the attended message (the message given to his left ear) and ignore the unattended message (the message given to his right ear).

Dichotic listening method

Selective Attention• Results of dichotic listening

– Participants could not report the content of the message in unattended ear

Broadbent’s filter model of attention.

• Sensory memory – Holds all incoming information for a

fraction of a second

– Transfers all information to next stage

• Filter– Identifies attended message based on physical

characteristics– Only attended message is passed on to the next

stage

• Detector– Processes all information to determine higher-

level characteristics of the message

Broadbent’s Filter Model• Early-selection model

– Filters message before incoming information is analyzed for meaning

Verifying Broadbent’s filter model

• Broadbent’s (1958) “split-scan” experiment

Two letters were presented to two ears at the same time

M H

R S

W P

Condition 1: subjects were asked to report the letters in any order

Two letters were presented to two ears at the same time

M H

R S

W P

Condition 2: subjects were asked to report pairs of letters in the order each pair was presented.

Results

M H

R S

W PCondition 2: subjects were asked to report pairs of letters in the order each pair was presented.

Accuracy 20%

Condition 1: subjects were asked to report the letters in any order

Accuracy 65%

Subjects tended to report all letters presented to one ear (MRW) and then to the other ear (HSP)

• Broadbent’s (1958) “split-scan” experiment– Easy: report information from one ear

and then the other

– Hard: Switching back and forth between ears

– It is difficult to switch attention between ears

“Cocktail party phenomenon”

– You are in a cocktail party.

– You are talking with someone intently.

– Somewhere, someone else mentions your name.

– You notice that even though your attention is fully committed to the person you were talking with.

• Ss were asked to shadow the message received to the left ear only.

• Left ear:– Dear 7 Jane

• Right ear:– 9 Aunt 6

• Shadowing report– Dear Aunt Jane

Treisman’s attenuation model of selective attention.

Tresiman’s Attenuation Theory

• Intermediate-selection model– Attended message can be separated

from unattended message early in the information-processing system

– Selection can also occur later

Task load and selective attention• Attention is more like resources

– Kahneman’s (1973) capacity theory– When a particular task demands lots of processing

resources, then other tasks get fewer resources.

Attention capacity

No task Hard task Easy task

Attention blink

• CogLab Attention blink

• (10 min)

• Attention blink: DVD

• (Q2) Under what conditions can we pay attention to more than one thing at a time?

Divided Attention• Practice enables people to simultaneously

do two things which at first were difficult– E.g., driving and singing

• After hours of practice, you can drive and sing.

• How does that happen?

• What makes a task(s) automatic?

• If you can transferring task information from short term memory to long term memory, you can make the task automatic.

Divided Attention• Schneider and Shiffrin (1977)

– Divide attention between remembering target and monitoring rapidly presented stimuli• Memory set: 1-4 target characters

• Test frames: could contain random dot patterns, a target, distractors

Caption: Consistent mapping condition for Schneider and Shiffrin’s (1977) experiment.

Caption: Improvement in performance with practice in Schneider and Schiffrin’s (1977) experiment. The arrow indicates the point at which participants reported that the task had become automatic. This is the result of experiments in which there were four target stimuli in the memory set and two stimuli in each frame.

Divided Attention

• Consistent mapping condition: target would be numbers, and distractors would be letters

• Over time, participants became able to divide their attention

• Automatic processing occurs without intention and only uses some of a person’s cognitive resources

Divided Attention

• Stroop effect – Name of the word interferes with the ability to

name the ink color– Cannot avoid paying attention to the meanings

of the words

Caption: Varied mapping condition for Schneider and Shiffrin’s (1977) experiment. This is more difficult than the consistent mapping condition because all the characters are letters and also because a character that was a distractor on one trial (like the T) can become a target on another trial, and a character that was in the memory set on one trial (like the P) can become a distractor on another trial.

Divided Attention

• Schneider and Shiffrin (1977)– Varied mapping condition: rules changed from

trial to trail– Over time, participants never achieved

automatic processing

Divided Attention

• Controlled processing: participants paid close attention, and their search was slow and controlled

Caption: Comparing performance on the consistent and varied mapping tasks. Note that the horizontal axis indicates the duration of each target frame. These graphs show that frames must be presented for longer durations to achieve good performance in the varied mapping condition.

% correct

• Controlled processing: participants paid close attention and their search was slow and controlled

• Strayer and Johnston (2001)– Simulated driving task

– Participants on cell phone missed twice as many red lights and took longer to apply the breaks• Same result using “hands-free” cell phone

Divided Attention• 100-Car Naturalistic Driving Study

– Risk of accident is four times higher when using a cell phone

• (Q3) How are attention and visual perception related?

Attention and Visual Perception• Inattentional blindness: a stimulus that is

not attended is not perceived, even though a person might be looking directly at it

– Video: the mind’s eye, • attention blink (Ch. 9-10)

Attention and Visual Perception• Change blindness: if shown two versions of

a picture, differences between them are not immediately apparent.

– http://viscog.beckman.illinois.edu/flashmovie/11.php

Visual Attention• Visual attention and eye movement

• Eye tracker

• Eye tracking machine and demo– http://www.youtube.com/watch?v=lGehsY7pcrc

• Attention helps select information.

• This is necessary because of the way the eye is structured.– Most cones reside around the fovea.– To get accurate information about a scene, we need to

select carefully particular parts of the scene.

Attention and Visual Processing

• Saccades – rapid movements of the eyes from one place to another

• Fixations – short pauses on points of interest

• Studied by using an eye tracker

Binding problem

• Visual features are assessed in a piece-meal fashion.

• How do you integrate those?

Caption: Steps in Treisman’s feature integration theory. Objects are analyzed into their features in the preattentive stage, and then the features are combined later with the aid of attention.

Feature Integration Theory (FIT)

• Preattentive stage– Automatic– No effort or attention– Unaware of process– Object analyzed into features

• Focused attention stage– Attention plays key role– Features are combined

Feature Integration Theory (FIT)

• Treisman and Schmidt (1982)– Ignore black numbers and focus on objects– Report what you saw at each of the 4 locations

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ch 6 62

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Illusionary conjunctions

• We tend to put different features from different objects together.

• brain damaged patients (parietal lobe) show illusionary conjunctions even when they view the stimuli for 10 seconds.

Unilateral neglect

Copies of the black (A) and

the white (B) vertical contour.

Copies of the black (A) and

the white (B) diagonal contour.

• Video Clip

– Unilateral neglect (The Mind Eye)

Additional materials

Attention and Visual Processing

• Stimulus salience – areas which stand out and attract attention– Bottom-up process

• Scene schema– Top-down process

Attention (executive function)

• Planning

• Rational thinking

• Controlling one’s emotion

Posner, M. I., Rothbart, M. K. (2007) Research on Attention networks as a model for the integration of psychological science. Annual Review of Psychology, 58, 1-23.

Read aloud each wordGreen

Yellow

Red

Orange

Blue

Violet

Red

Yellow

Green

Raven test: (Carpenter, Just, & Shell, 1990)

Attention revisited

• Human– Executive control– Metacognitive ability (controlling your own

attention / cognition) and deploying your cognitive resources to achieve goals.