Chapter 8- Visual Motion Perception

Question 1

Motion Affereffect (MAE)

Answer 1

The illusion of motion of a stationary object that occurs after prolonged exposure to a moving object.

Question 2

Interocular Transfer

Answer 2

The transfer of an effect (such as adaptation) from one eye to the other.

Question 3

Middle Temporal Area (MT) (VS)

Answer 3

An area of the brain thought to be important in the perception of motion. Also called VS in humans.

Question 4

Apparent Motion

Answer 4

The illusory impression of smooth motion resulting from the rapid alternation of objects that appear in different locations in rapid succession.

Question 5

Aperture

Answer 5

A windowlike opening that allows only a partial view of an object.

Question 6

Correspondence Problem

Answer 6

In reference to motion detection, the problem faced by the motion detection system of knowing which feature in Frame 2 corresponds to a particular feature in Frame 1.

Question 7

Aperture Problem

Answer 7

The fact that when a moving object is viewed though an aperture (or a single receptive field), the direction of motion of a local feature or part of the object may be ambiguous.

Question 8

First-Order Motion

Answer 8

The motion of an object that is defined by changes in luminance (reflected light).

Question 9

Luminance-Defined Object

Answer 9

An object that is delineated by differences in reflected light.

Question 10

Second-Order Motion

Answer 10

The motion of an object that is defined by changes in contrast or texture, but not by luminance.

Question 11

Texture-Defined Object or Contrast-Defined Object

Answer 11

An object that is defined by differences in contrast, or texture, but not by luminance.

Question 12

Akinetopsia

Answer 12

A rare neuropsychological disorder in which the affected individual cannot perceive motion.

Question 13

Double Dissociation

Answer 13

The phenomenon in which one of two functions, such as first- and second-order motion, can be damaged without harm to the other, and vice versa.

Question 14

Optic Array

Answer 14

The collection of light rays that interact with objects in the world that are in front of a viewer. The term was coined by J. J. Gibson.

Question 15

Optic Flow

Answer 15

The changing angular positions of points in a perspective image that we experience as we move through the world.

Question 16

Focus of Expansion

Answer 16

The point in the center of the horizon from which, when we’re in motion (e.g,, driving on the highway), all points in the perspective image seem to emanate. The focus of expansion is one aspect of optic flow.

Question 17

Time to Collision (TTC)

Answer 17

The time required to a moving object, (such as a cricket ball) to hit a stationary object (such as a batsman’s head). TTC= Distance/Rate.

Question 18

Tau (t)

Answer 18

Information in the optic flow that could signal time to collision (TTC) without the necessity of estimating either absolute distances or rates. The ratio of the retinal image size at any moment to the rate at which the image is expanding is tau, and TTC is proportional to tau.

Question 19

Biological Motion

Answer 19

The pattern of movement of living beings (humans and animals).

Question 20

Saccade

Answer 20

A type of eye movement, made both voluntarily and involuntarily, in which the eyes rapidly change fixation form one object or location to another.

Question 21

Smooth Pursuit

Answer 21

A type of voluntary eye movement in which the eyes move smoothly to follow a moving object.

Question 22

Superior Colliculus

Answer 22

A structure in the midbrain that is important in initiating and guiding eye movements.

Question 23

Microsaccade

Answer 23

An involuntary, small, jerky eye movement.

Question 24

Reflexive Eye Movement

Answer 24

A movement of the eye that is automatic and involuntary.

Question 25

Optokinetic Nystagmus (OKN)

Answer 25

A reflexive eye movement in which the eyes will involuntarily track a continually moving object.

Question 26

Vergence

Answer 26

A type of eye movement in which the two eyes move in opposite directions; for example, both eyes turn toward the nose (convergence) or away form the nose (divergence).

Question 27

Saccadic Suppression

Answer 27

The reduction of visual sensitivity that occurs when we make saccadic eye movements. Saccadic suppression eliminates the smear from retinal image motion during an eye movement.

Question 28

Efference Copy or Corollary Discharge Signal

Answer 28

The phenomenon in which outgoing (efferent) signals from the motor cortex are copied as they exit the brain and are rerouted to other areas in the sensory cortices.

Question 29

Comparator

Answer 29

An area of the visual system that receives one copy of the command issued by the motor system when the eyes move (the other copy goes to the eye muscles). The comparator compares the image motion signal with the eye motion signal and can compensate for the image changes caused by the eye movement.