Chapter 4-Attention Pt. 2

Question 1

Overt Attention

Answer 1

Eye movements, attention, perception

Saccades: rapid movements of the eyes from one place to another

Fixations: short pauses on points of interest (studied by using an eye tracker)

Question 2

Stimulus Salience

Answer 2

Areas that stand out and capture attention

• bottom up process
• depends on characteristics of the stimulus
• colour and motion are highly salient

Question 3

Scene Schema

Answer 3

Knowledge about what is contained in typical scenes

• top down process
• help guide fixations from one area of a scene to another

Question 4

Eye movements are determined by ______

Answer 4

Task

Eye movements preceded motor actions by a fraction of a second

Question 5

Vo and Henderson

Answer 5

• top down process and eye movement
• kitchen scene
• participants looked longer at the printer than at the pan
• demonstrates how eye movement is guided by people’s previous knowledge

Question 6

Covert Attention

Answer 6

Attention without eye movements

Question 7

Precueing

Answer 7

Directing attention without moving the eyes

Participants respond faster to a light at an expected location than at an unexpected location even when the eyes are kept fixed

Question 8

Attentional cues experiment

Answer 8

Posner

Focus visual attention to an area using a cue

Measure time to identify target when:

• observer does not know where item will appear
• observer does know where item will appear

Question 9

Results: cue versus no cue

Answer 9

Advance knowledge of location improves performance

Amount of reduction depends on distance from cue (Downing and Pinker 1985)

Question 10

Exogenous cue

Answer 10

Outside generating

• low level reflexes
• sudden change (e.g. flash or movement)
• draws attention automatically
• bottom up control of attention
• based on what is actually happening in the environment

Question 11

Endogenous cues

Answer 11

Inside generating

-high level control
-instruction (via some kind of visual sign or pattern)
-sends attention to requested location
-top down control of attention
-based on what the observer believes
E.g. interpreting meaning of the arrow

Question 12

Inhibition of return (IOR)

Answer 12

Klein (2000)

If the time interval between cue and target are too long you will see opposite results (e.g. valid cue becomes longer than invalid)

People first direct their attention to the direction of the cue. After 200 ms interval passes before target is shown, Attention is shifted to the opposite direction than suggested by the valid cue

Question 13

In addition to paying attention to the location of objects (via spatial cues), people can also ______

Answer 13

Pay attention to the movement of objects

Question 14

Object Based Visual Attention

Answer 14

Location based: moving attention from one place to another

Object based: attention being directed to one place on an object

Question 15

Egly et. al

Answer 15

• 1994
• object based visual attention
• participants saw two side by side rectangles, followed by a target cue
• reaction time fastest when target appeared where indicated (A)
• reaction time faster when target appeared in same rectangle (B) even though B and C had same DISTANCE to cue

Question 16

Attention can be based on

Answer 16

The environment (static scenes or scenes with a few objects)

Specific object (dynamic events)

The enhancing effect of attention spreads throughout the object

Question 17

Divided Attention

Answer 17

Practice allows people to simultaneously do two things that were difficult at first

Schneider and Shiffrin (1977)

• memory set (1-4 target characters)
• test frames (contained distractors, flashed rapidly)

Had to remember the memory set and say if it appeared in the test frames

Question 18

Results of Schneider and Shiffrin’s divided attention experiment

Answer 18

After 600 trails people were able to divide their attention (practice allowed for this)

Question 19

Automatic processing

Answer 19

Occurs without intention and only uses some of a person’s cognitive resources

Question 20

Divided attention-distractions while driving

Answer 20

100 car naturalistic driving study:

• video recorders placed in cars
• risk of accident is four times higher when using a cell phone

Strayer and Johnston (2001):

• simulated driving task
• participants on cell phone missed twice as many red lights and took longer to apply breaks (same results for hands free cell phones)

Question 21

Inattentional blindness

Answer 21

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

Question 22

Inattentional blindness experiment

Answer 22

One green horizontal line and one blue vertical line

Participants had to say which was longer

On the 6th trial a small square is included in the display (participants couldn’t recall seeing it)

Question 23

Change blindness

Answer 23

If shown two versions of a picture, differences between them are not immediately apparent

-task to identify differences requires concentrated attention and search

This is because we are paying more attention to the movement between the pictures

Question 24

Change detection experiment

Answer 24

-Person in gorilla suit that walked through basketball game

-flicks versus no flicks
Grey screen between two images (flick) result in less right and takes longer
No flicker gives motion signal that allows you to detect change easily

Question 25

Explanation of change blindness

Answer 25

Attention is needed to see change
-without it observers are change blind

Our actual sensory representations are sparse
-little is retained over time

Question 26

In everyday life we usually see ______

Answer 26

Change

• if something changes, creates a motion signal
• motion is an exogenous cue (draws attention)
• if something interferes with drawing of attention (flicker) then Attention doesn’t go to change

Question 27

Binding

Answer 27

The process by which features such as colour, form, motion, and location are combined to create our perception of a coherent object

Refers to a FIT

Question 28

FIT can predict

Answer 28

Illusory conjunctions

Question 29

Physiology of Attention

Answer 29

Attention enhances neural responding

Attentional processing is distributed across a large number of areas in the brain

Question 30

fMRI to detect cortical activity during a search task

Answer 30

Showed that attention to an expected direction of motion caused brain activity to increase in a number of brain areas

E.g. person looking at a patterned disc

Question 31

Attentional blink

Answer 31

Visual search reflexes the spatial properties of our attention and attentional blink reflexes the temporal properties of our attention

Question 32

Attentional blink experiment

Answer 32

Raymond et.al (1992)

Experimental condition: identify the white target and report whether there is the probe X by pressing a button

Control condition: only report whether there is the probe X. In half trials, there was no probe X

Question 33

Attentional blink experiment results

Answer 33

For control condition subjects correctly detected the probe on 85% trials

For the experimental condition the detection of the percentage correct dropped below 60%

This is because when two targets are presented within 500 ms of each other, subjects are unable to report the second target

Attentional blink is not the result of perceptual memory or response output limitation but because allocation of attention to the first object leaves less attention for the second

Question 34

As temporal separation ______, identification of the second letter ______

Answer 34

Increases

Improves