L6 - Perception (to do)

Question 1

What two phases are needed for using visual information for action?

Answer 1

Planning phase

Guiding phase

Question 2

What did Kowler & McKee (1987) find in their visual information experiment?

Answer 2

That visual information (e.g. target location, speed) is used to plan and guide eye movements

Question 3

What is a “smooth pursuit eye movement”?

Answer 3

The eye movement you make when tracking an object

Question 4

What are involved when “planning a reach”?

Answer 4

1. Reaches are planned in eye-centred coordinates
   * Suggests visual localisation reference framework is important when making a hand movement (if goal directed you are using this eye-centered coordinate as a reference frame to help you find where this thing is in space)*
2. Reaches are planned using re-mapped target locations
   * Re-mapping occurs when you make an eye-movement*
3. Eye and hand movements are planned with respect to a common framework
   * You use the same framework when you update your movements when you interact with your environments*

Question 5

Using eye-tracking software while doing everyday tasks, what did Land, Mennie and Rusted (1999) discover?

Answer 5

The eye and the hand movements were quite co-ordinated, more than originally thought.

People put their hands where their eyes had been.

Question 6

What is a “saccade”

Answer 6

Eye movement characterised by rapid acceleration to new location

Question 7

What does a saccade allow us to do?

Answer 7

Allows us to foveate points of interest

Question 8

What are smooth pursuit eye movements characterised by?

Answer 8

A constant velocity once at the same speed as target

Question 9

What do smooth pursuit eye movements allow us to do?

Answer 9

Allows us to track an item of interest

(often seen with a saccade)

Question 10

How often are saccades made?

Answer 10

3 times a second

Question 11

Is the visual information we use to make perceptual judgements the same as the visual information we use to make smooth pursuit eye movements and saccades?

Answer 11

Yes

Similar visual information is used to guide eye movements and make perceptual judgements

Question 12

Saccade movements are changed by the quality of the information.

What does this suggest?

Answer 12

You are using the visual information to program and control that eye movements

Question 13

Eye movements are more variable when visual information is ___

What does this suggests

Answer 13

Visual information is poor

Suggests that the variability of the eye signal is comparable to the visual signal, which means they are using a common signal

Question 14

Eye movements and hand movements have a _____ signal

Answer 14

common signal

Question 15

What happened in the Pellison et al (1986) and Henriques et al (1996) experiments when they measured the accuracy of pointing performance when altering the direction of their gaze?

Answer 15

Accuracy was decreased when direction of gaze was not in the same direction they were asked to point

Question 16

What do we use to plan a “sequence of slow guided movements” (e.g. moving our hand around a table to make a sandwich) (Hayhoe, 2000)

Answer 16

“Look ahead Saccades”

Our saccades are used to gather information regarding what our hands are about to do next

Question 17

Saccades are used as an _______ gathering device

Answer 17

information

Question 18

Which area of the eye is most high resolution?

Answer 18

Fovea

Question 19

Why do we need to make so many Saccades?

Answer 19

Because we have low amounts of visual acuity in our peripheral vision,

We need to constantly refocus our eyes to gather accurate information

Question 20

You know from experience that the world is high resolution across the visual field.

True or false

Answer 20

False

Visual resolution varies across the visual field

Question 21

Do we make our saccade movements randomly or do we have a strategy?

Answer 21

We use saccades strategically - Yarbus (1967)

Question 22

How did Yarbus (1967) show that we use saccades strategically?

Answer 22

Asked people to view a picture in 5 different ways and measured their saccade movements.

Saccades differed depending on the goals of the viewer

Question 23

Saccades are random

True or false

Answer 23

False

Saccades are NOT random (Yarbus 1967)

Question 24

What is “saccade latency”

Answer 24

The time between when the stimulus appears and when your eyes move

Question 25

How long is the **saccade latency**?

Answer 25

150ms-200ms

Question 26

How long does a **saccade** take? (How long is it "in flight")

Answer 26

20-50ms depending on the length the eye has to travel

Question 27

Including all stages of the saccade, roughly how long does it take?

Answer 27

300ms

Question 28

What did this Renniger, Coughlan, Verghese & Malik (2005) experiment reveal about the nature of how people use saccades?

Answer 28

That we use information to maximise the amount of new information about an object

Question 29

How did Renniger, Coughlan, Verghese & Malik (2005) determine that each eye movement maximises the amoutn of new info on the object?

Answer 29

They would move their eye movements to where the object is "changing" or different. Where the curviture changes and there are new features.

Question 30

The ____ saccades you do, the ______ your ______ of a scene is.

Answer 30

1) more 2) greater 3) memory The **more** saccades you do, the **greater** your **memory** of a scene is.

Question 31

What are 3 reasons why you would move your eyes?

Answer 31

1. Limited spatial resolution in the periphery 2. Shifting the eyes shifts the fovea to get a higher resolution info about the environment 3. Gather information for perception and action

Question 32

Why is it important to coordinate the eye and hand?

Answer 32

Goals are usually visually defined * Visual info about target location* * Visual feedback about hand position (relative to target)* * If you co-ordinate eye and hand you get more information*

Question 33

What is a **corollary discharge?**

Answer 33

When you make a movement you get a proprioceptive feedback from the muscles that says "I made that movement" - *this is corollary discharge*

Question 34

What relationship does corollary discharge have with the eyes and with the hands?

Answer 34

It's associated with eye movement Aids guidance of hand movement

Question 35

Are people better at finding a target with their hands if they - Are in a light room but can't make a saccade Are allowed to use a visual saccade but in the dark Why

Answer 35

Allowed to use a visual saccade but in the dark The corollary discharge from the eye movement helps guide the hand movement

Question 36

During rapid pointing The ____ typically leads the hand

Answer 36

The **eye** typically leads the hand

Question 37

Eye and hand movements are ususally ______ and ______ correlated

Answer 37

Temporally and spatially *Eye and hand movements are ususally **temporally and spatially** correlated*

Question 38

What part of the brain is responsible for target selection?

Answer 38

**Superior colliculus**

Question 39

How did McPeek and Keller (2005) determine what part of the brain is responsible for target selection

Answer 39

When administering a drug to the **superior colliculus** that deactivated it, participants were no longer able to find new targets

Question 40

Visual processing pathway - Retina - _______ - Pulvinar - Parietal cortex What is missing?

Answer 40

Superior Colliculus

Question 41

What did **Moore and Fallah (2004)** find in regards to attention and eye movement?

Answer 41

There are some shared mechanisms for deploying attention and making an eye movement.

Question 42

One a decision is made and a saccade is "in flight" there are no new decisions to be made True or False

Answer 42

False There is a complex circuit and decisions are constantly being made (e.g. where you are going next)

Question 43

Describe the Itti & Koch (2001) model.

Answer 43

1. You have scene info around you (vis info) 2. Info gets fed to Inferotemporal or posterior parietal cortex 3. Info goes to prefrontal cortex 4. Info goes to motor systems + memory and cognition - superior colliculus 5. Superior colliculus leads to eye movement

Question 44

What is the **prefrontal cortex** involved in?

Answer 44

(involved in inhibition of responses/decision making)

Question 45

\_\_\_\_ information is used to guide eye and hand movements

Answer 45

**visual**

Question 46

Two common types of eye movements are

Answer 46

saccades and smooth pursuit

Question 47

Eye and hand movements are often \_\_\_\_\_\_\_

Answer 47

co-ordinated

Question 48

Eye movements and the deployment of attention can be..

Answer 48

**related**

Question 49

Exam prep notes last slide Use lecture summaries and SDLs as a study guide Practice exam questions on canvas

Answer 49

Good luck!