Lecture 11

Question 1

3 examples of motion

Answer 1

1) An object moves, and the observer is stationary
2) An object moves, and the observer follows the object with their eyes
3) An observer moves their eyes through- scans- a stationary environment

Question 2

The situation/example of motion where you look straight as an object moves past… object, eyes, images of observer’s retina, object movement perceived

Answer 2

object: moves
eyes: stationary
image of observer’s retina: moves
object movement perceived?: yes

Question 3

The situation/example of motion where you follow a moving object with eyes… object, eyes, images of observer’s retina, object movement perceived

Answer 3

object: moves
eyes: move
images of observer’s retina: stationary
object movement perceived?: yes

Question 4

The situation/example of motion where you look around the room… object, eyes, images of observer’s retina, object movement perceived

Answer 4

object: stationary
eyes: move
images of observer’s retina: moves
object movement perceived?: no

Question 5

ecological approach

Answer 5

focusses on what/how information directly available in the environment is useful to guide perception/action

Question 6

optic array

Answer 6

structure created by surfaces, textures, and contours in the environment, which change as the observer moves through space

Question 7

Gibson thought that optic array can be used to explain when motion is and is not perceived with reference to 2 basic kinds of changes …

Answer 7

1) Local disturbances in the optic array
2) Global optic flow

Question 8

Local disturbances in the optic array

Answer 8

objects moving relative to background e.g. such that portions of stimuli are periodically covered and uncovered- background and objects

Question 9

Global optic flow

Answer 9

overall movement of the entire optic array (as a complete whole i.e. without any local disturbances)

Question 10

If the optic array changes in a uniform way i.e. entirety of optic array all moves in exactly same way, then motion ___ be perceived

Answer 10

If the optic array changes in a uniform way i.e. entirety of optic array all moves in exactly same way, then motion will not be perceived

Question 11

Perceiving motion

Answer 11

when one part of the visual scene moves relative to the rest of the scene

Question 12

Not perceiving motion

Answer 12

when the entire field moves, or remain stationary

Question 13

Corollary discharge theory

Answer 13

hypothesizes that movement depends on 3 signals: 1) Image displacement signal (IDS), 2) Motor signal (MS), 3) Corollary discharge signal (CDS)

Question 14

Image displacement signal (IDS)

Answer 14

movement of image stimulating receptors across the retina

Question 15

Motor signal (MS)

Answer 15

signal sent to eyes to move eye muscles

Question 16

Corollary discharge signal (CDS)

Answer 16

derived from the motor signal (essentially a ‘carbon copy’ of whatever the motor signal is doing, though it gets sent to a different part of the brain for another purpose)

Question 17

Movement is perceived when comparator receives input from EITHER (but not both)…

Answer 17

corollary discharge signal or image displacement signal

Question 18

Movement is NOT perceived when comparator receives input, at the same time, from BOTH…

Answer 18

corollary discharge signal and image displacement signals

Question 19

Real-movement neurons found in monkeys..

Answer 19

responds when a stimulus moves but not when the eyes move

Question 20

Reichardt detectors

Answer 20

model of a simple neural circuit that could fire in response to movement in one direction

Question 21

Output unit

Answer 21

compares the signals it receives from two neurons to determine whether they are synchronized i.e. received at exactly the same time

Question 22

delay unit

Answer 22

slows down the speed of transmission of the signal to the output unit

Question 23

If the timing is right, and the delay unit ‘__’ the signal from neuron A until the signal from neuron B naturally arrives at the output unit, that output unit will ____ and rightward ___ will be perceived

Answer 23

If the timing is right, and the delay unit ‘holds onto’ the signal from neuron A until the signal from neuron B naturally arrives at the output unit, that output unit will fire and rightward motion will be perceived

Question 24

Reichardt detectors are ___, meaning that each one can only detect motion in ___ ___ (need one configuration to register leftward motion, and a slightly different one to register rightward motion)

Answer 24

Reichardt detectors are directional, meaning that each one can only detect motion in one direction (need one configuration to register leftward motion, and a slightly different one to register rightward motion)

Question 25

Perception of motion begins in ___ ___ (___), the region of the occipital lobe where information from the retinas first reach the cortex

Answer 25

Perception of motion begins in striate cortex (V1), the region of the occipital lobe where information from the retinas first reach the cortex

Question 26

Complex cortical cells

Answer 26

respond to movement of the ends of objects

Question 27

Middle temporal area (MT)

Answer 27

implicated in other aspects of motion perception

Question 28

Transcranial magnetic stimulation (TMS)

Answer 28

applied to MT in humans disrupts ability to perceive direction in a random pattern of moving dots

Question 29

shortest path constraint

Answer 29

apparent movement tends to occur along the shortest path between 2 stimuli

Question 30

Biological motion

Answer 30

self-produced motion of a person or other living organism

Question 31

Biological motion can help with ___ ___

Answer 31

Biological motion can help with perceptual organization

Question 32

Point-light walker stimulus

Answer 32

created by placing light on joints of a living organism, which convey their pattern of movement (and thus, conveys biological motion)

Question 33

Superior temporal sulcus (STS) are more active for ___ motion

Answer 33

Superior temporal sulcus (STS) are more active for biological motion

Question 34

Grossman et al. found TMS applied to ___ decreased the participants’ ability to detect biological motion

Answer 34

Grossman et al. found TMS applied to STS decreased the participants’ ability to detect biological motion

Question 35

Striate Cortex (V1) function related to motion

Answer 35

direction of motion across small receptive fields

Question 36

Middle temporal area (MT) function related to motion

Answer 36

direction and speed of object motion

Question 37

Medial superior temporal area (MST) function related to motion

Answer 37

processing optic flow; locating moving objects; reacting for moving objects

Question 38

Superior temporal sulcus (STS) function related to motion

Answer 38

perception of motion related to animals and people (biological motion)

Question 39

Implied motion is conveyed by…

Answer 39

still pictures that depict an action which involves motion

Question 40

Representational momentum

Answer 40

implied motion depicted in a photo can be ‘carried out’ or continue in the observer’s mind

Question 41

Control condition in Freyd’s Implied motion study

Answer 41

same photo as shown before

Question 42

Time-forward condition in Freyd’s implied motion study

Answer 42

an image that would have happened slightly later than the one they actually saw

Question 43

Time-backward condition in Freyd’s implied motion study

Answer 43

an image that would have happened slightly earlier than the one they actually saw

Question 44

participants were found to take longer to respond to __-__ pictures as compared to __- __ pictures

Answer 44

participants were found to take longer to respond to time-forward pictures as compared to time- backward pictures