Question 1

Distance perception or depth perception

Accepted Answer

refers to your ability to perceive the distance relationships within the visual scene. We can think of three different types of distance or depth relationships:

Question 2

egocentric distance

Accepted Answer

refers to the distance of an object from you the observer. Egocentric literally means “self

Question 3

relative distance

Accepted Answer

refers to how far two objects are from each other. Because the distance does not directly involve the observer it is called allocentric distance “other”. Is the library or gym closer to the dining hall.

Question 4

you perceive objects as three dimensional. In addition to height and width, objects have

Accepted Answer

depth or thickness. Thus you see the textbook as a solid object with the open pages closer to you than the parts of the cover you can see.

Question 5

A cue

Accepted Answer

is a factor that enables you to make a decision automatically and spontaneously. Because they require only one eye to be effective, these are monocular cues.

Question 6

Many monocular cues

Accepted Answer

most of our sources of information about distance are monocular. this is why there have been athletes who were very successful with vision in one eye.

Question 7

Pictorial depth cues (monocular)

Accepted Answer

static cues that do not move. Artists have learned to use these cues to represent distance in a picture.

Question 8

occlusion

Accepted Answer

also called interposition or overlap, means that one object partially covers another. When interposition occurs, we judge the partly covered object to be farther away than the object completely visible.

Question 9

ex: the book looks closer to me than the table its covering. The ring on my finger looks closer to me than the part of the finger it’s covering.

Accepted Answer

also called interposition or overlap, means that one object partially covers another. When interposition occurs, we judge the partly covered object to be farther away than the object completely visible.

Question 10

occlusion gives rise to a sense of depth in moving displays. It plays an important role in conjunction with the binocular cue of disparity.

Accepted Answer

Occlusion pt. II

Question 11

linear perspective

Accepted Answer

is a strategy used by artists to represent a three

Question 12

ex: to draw parallel railroad tracks, an artist would have to draw the two tacks so that they meet at a vanishing point on the horizon. The true distance between the railroad tracks remains constant.

Accepted Answer

is a strategy used by artists to represent a three

Question 13

Size cues

Accepted Answer

refer to the influence of an object’s size on distance estimates. One size cue comes from familiar objects.

Question 14

the familiar size

Accepted Answer

of an object can be a helpful cue because objects are often found in standardized sizes.

Question 15

ex: if a book occupies a tiny space on your retina, you will judge it to be far away. Familiar size may be an effective cue for relative distance as well. However others cues to distance are more effective.

Accepted Answer

of an object can be a helpful cue because objects are often found in standardized sizes.

Question 16

many objects don’t come in a standard size and other objects are completely novel. Would the relative size

Accepted Answer

of a novel object the object’s size relative to other objects be a helpful cue in telling us which of the two is closer?

Question 17

the size of the retinal image is an ambiguous cue. A large retinal image may be due to a distant large object or nearby small object, thus perceived distance is quite important when judging the size of an object.

Accepted Answer

of a novel object the object’s size relative to other objects be a helpful cue in telling us which of the two is closer?

Question 18

ex: The Williams Ittelson and Franklin Kilpatrick study where they asked people to judge the distance of two balloons. People reported the larger balloon appeared closer.

Accepted Answer

Ballon Example

Question 19

Texture gradients

Accepted Answer

refer to when you view surfaces at a slant, the texture of surfaces become denser as the distance increases. This cue is related to linear perspective. (Think railroad track)

Question 20

James Gibson among the first psychologists to emphasize role of texture gradients in distance perception.

Accepted Answer

Texture gradients provide a scale by which we can measure objects, thus a nearby object that hides three texture unties is the same size as the distance object that hides three texture units.

Question 21

texture units are such powerful cues to depth that even simple schematic representations are sufficient to produce a clear sense of depth.

Accepted Answer

Texture explination

Question 22

atmospheric perspective

Accepted Answer

aerial perspective refers to the observation that distant objects often look blurry and bluish in contrast to nearby objects because of air between you and the distant objects which are not perfectly clear.

Question 23

Shading

Accepted Answer

is a cue provided by the pattern of light and shadows. Objects may cast shadows onto other objects or it may have shadows attached to its surface.

Question 24

During Halloween people place lights under their faces to distort it when teling ghost stories.

Accepted Answer

Shading helps define the shape of objects because it provides information about parts of an object that stick out or cave inward.

Question 25

Height cues or elevation cues

Accepted Answer

refer to the observation that objects near the horizon appear to be farther away from us than objects far from the horizon.

Question 26

Ex: Think of looking out on Lake Ponchatrain during a sunset. The sun is in the horizon and is farther away that the puffy clouds overhead which are higher in the sky.

Accepted Answer

refer to the observation that objects near the horizon appear to be farther away from us than objects far from the horizon.

Question 27

Pictoral depth cues on two dimensional surfaces

Accepted Answer

pictorial depth cues were not readily apparent to ancient artists. But modern painters are aware but some are not concerned about the accurate representation of distance. Artists intent on accurately depicting a three

Question 28

Trompe l’oeil

Accepted Answer

is French for “fool the eye” and some pictures are so effective they hardly seem two

Question 29

Monocular depth cues involving motion. Most of your visual experience involves moving objects or moving retinas as you turn your head and move your body past objects.

Accepted Answer

is French for “fool the eye” and some pictures are so effective they hardly seem two

Question 30

Motion Parallax

Accepted Answer

Objects at different distances appear to move in different directions and at different speeds. Parallax means a change in position so motion parallax is a change in the position of an object that is caused by your motion.

Question 31

MP is a good source of both shape and distance information but its effectiveness depends on the pursuit of eye movements. Retinal changes due to mp would be similar for near or distant objects.

Accepted Answer

Motion Parallax pt. II

Question 32

Think of driving in a car, the speed limits sign pass by more quickly than do the trees in the distance because the signs are closer to you.

Accepted Answer

Example of MP

Question 33

Kinetic depth effect.

Accepted Answer

Ex: A paper clip looks flat but when it is rotated in the air it looks three dimensional.

Question 34

BD Example

Accepted Answer

This can be demonstrated by holding your left thumb 6 inches from your eyes and to the left and holding the right thumb 2 feet directly ahead. BD is important because it provides the information needed to judge depth binocularly, an ability known as

Question 35

Binocular disparity.

Accepted Answer

Your two eyes have slightly different views of the world whenever nearby objects are at different distances. BD refers to the different information that is registered on the two eyes.

Question 36

Using a focal point, an imaginary curved line called the

Accepted Answer

horopter can be drawn to represent all the points that are equally distant from the observer. If your thumbs were positioned the same as in the BD example, imagine a curved line passing through your right thumb and continuing on either side but always 2 f

Question 37

objects on the horopter and near the horopter in an areas called

Accepted Answer

panum’s area can be fused into a single image. Outside of Panum’s area, objects will typically produce double images.

Question 38

objects in front of the horopter create

Accepted Answer

crossed disparity because the image crosses to the outside of the focal point on each retina.

Question 39

objects behind the horopter create

Accepted Answer

uncrossed disparity

Question 40

BD is primarily effective for perceiving depth in nearby objects. People more accurately judge the distance of nearby objects when they use binocular information rather than just monocular information. Whether judging distance monocularly or binocularly p

Accepted Answer

which is a cue that objects are far from us.

Question 41

Using BD to create depth in pictures.

Accepted Answer

Charles Wehatstone invented the stereoscope, an instrument that has contributed greatly to out knowledge about depth perception.

Question 42

A stereoscope

Accepted Answer

is a piece of equipment that presents two photographs of a scene taken from slightly different viewpoints. Typically these viewpoints are sepatated to the same extent as human eyes. (2.5 inches)

Question 43

A stereoscopic picture

Accepted Answer

consists of two pictures, one for the right eye and one for the left eye. When the two pictures are seen at the same time they combine to make a three-dimensional scene.

Question 44

Problem with stereoscopic pics

Accepted Answer

One problem with using stereoscopic pictures to study stereopsis is they often incorporate pictorial depth cues in addition to binocular disparity. So you could not know for sure that the sense of depth emerged solely from the binocular information.

Question 45

Bela Julesz developed

Accepted Answer

random dot stereograms. Neither of the two images make sense when viewed alone, thus only stereopsis can explain the apparent depth that emerges when the two images are fused.

Question 46

Class of illusory depth experiences (closely related to random dot stereograms)

Accepted Answer

When presented with a repetitive pattern like repeating wallpaper or rows of tiny dots on ceiling or floor tiles, people often teport that part of the pattern seems to pop out toward them.

Question 47

Essentially the sense of depth that emerges from such stimuli arises because the visual system devises an inappropriate solution to the correspondence problem. The correspondence problem

Accepted Answer

is the difficulty our visual system can face in linking the input from the two retinas. Ordinarily, the input from the two retinas is so distinctive that the solution to the correspondence problem is relatively simple.When you look at your textbook with f

Question 48

an autostereogram

Accepted Answer

is a single image that contains binocular depth information when viewed appropriately. The Magic Eye books contain these images. You visual system can solve the correspondence problem of the autostereogram in at least two ways.

Question 49

Solution to autostereogram

Accepted Answer

a flat random pattern you will see if you just glance at the figure. • in another you seem to be looking through the page as though into a window.

Question 50

Binocular Rivalry.

Accepted Answer

The different images presented to the two eyes are typically fused into a single image containing depth information leading Julesz to refer to the percept as cyclopean. (Think one eyed Cyclops from Greek mythology).

Question 51

Eye Muscle Cues to Depth

Accepted Answer

two other potential cues to depth aren’t based on retinal information. They are based on input from the muscles that control the shape of the lens or the position of two eyes. Accomodation and convergence.

Question 52

Accommodation

Accepted Answer

is the change in the shape of the lens in your eye as you focus on objects at different distances. The lens is thin to view distant objects and thick to view nearby objects. eye muscles that control lens shape respond differently to objects

Question 53

Convergence

Accepted Answer

means the eyes converge, or move inward together to look at nearby objects.

Question 54

Approaches to distance perception.

Accepted Answer

There are three major theoretical approaches to distance perception: the Gibsonian position, the empiricist position, and the computational approach. The Gibsonian position, the empiricist position and computational approach.

Question 55

Direct Perception or Gibsonian approach

Accepted Answer

was summarized by James Cutting who said “for Gibson, information was present in the environment and needed only to be picked up”. Gibson argued the stimulus contains sufficient information to allow for correct perception.

Question 56

Gibson emphasized the importance of texture gradients as a source of information about distance. Texture gradients provide a scale where we can measure objects distances from us and his emphasis is more on his general ground theory.

Accepted Answer

According to ground theory -distance perception depends on information provided by surfaces in the environment.

Question 57

Either observers or objects are likely to be moving. Gibson proposed motion parallaxis part of a more general motion patter he calls motion perspective.

Accepted Answer

refers to the continuous change in the way objects look as you move about in the world.

Question 58

As you directly approach a point straight ahead, objects on all sides seem to move away from that point. For example as you walk between the rows of books in the library, staring straight ahead, you should have the sense of motion perspective.

Accepted Answer

Example of Motion Perspective

Question 59

Gibson emphasized the concept of affordances

Accepted Answer

actions that a person could perform with objects.

Question 60

The Empiricist approach. Empircism

Accepted Answer

is a philosophical approach stating that all information is derived from sensory perceptions and experiences.

Question 61

Example of Ground Theory

Accepted Answer

Looking out the window, objects do not float in the air, instead the ground serves as their background so distance can be seen more directly. Other surfaces like ceilings also provide useful information about depth.

Question 62

Example of Empiricism

Accepted Answer

We are not born knowing how to perceive distance, we must acquire this skill by learning.

Question 63

Bishop Berkeley outlined the empiricist position addressing the problem

Accepted Answer

the stimulus registered on the retina has only the dimensions height and width. We also see depth or distance but how can we judge the distance of an object if we cannot sense distance in and of itself?

Question 64

Kinesthetic information

Accepted Answer

nonvisual information that includes all the muscular information we receive as we interact with objects.

Question	Answer
Distance perception or depth perception	refers to your ability to perceive the distance relationships within the visual scene. We can think of three different types of distance or depth relationships:
egocentric distance	refers to the distance of an object from you the observer. Egocentric literally means “self
relative distance	refers to how far two objects are from each other. Because the distance does not directly involve the observer it is called allocentric distance “other”. Is the library or gym closer to the dining hall.
you perceive objects as three dimensional. In addition to height and width, objects have	depth or thickness. Thus you see the textbook as a solid object with the open pages closer to you than the parts of the cover you can see.
A cue	is a factor that enables you to make a decision automatically and spontaneously. Because they require only one eye to be effective, these are monocular cues.
Many monocular cues	most of our sources of information about distance are monocular. this is why there have been athletes who were very successful with vision in one eye.
Pictorial depth cues (monocular)	static cues that do not move. Artists have learned to use these cues to represent distance in a picture.
occlusion	also called interposition or overlap, means that one object partially covers another. When interposition occurs, we judge the partly covered object to be farther away than the object completely visible.
ex: the book looks closer to me than the table its covering. The ring on my finger looks closer to me than the part of the finger it’s covering.	also called interposition or overlap, means that one object partially covers another. When interposition occurs, we judge the partly covered object to be farther away than the object completely visible.
occlusion gives rise to a sense of depth in moving displays. It plays an important role in conjunction with the binocular cue of disparity.	Occlusion pt. II
linear perspective	is a strategy used by artists to represent a three
ex: to draw parallel railroad tracks, an artist would have to draw the two tacks so that they meet at a vanishing point on the horizon. The true distance between the railroad tracks remains constant.	is a strategy used by artists to represent a three
Size cues	refer to the influence of an object’s size on distance estimates. One size cue comes from familiar objects.
the familiar size	of an object can be a helpful cue because objects are often found in standardized sizes.
ex: if a book occupies a tiny space on your retina, you will judge it to be far away. Familiar size may be an effective cue for relative distance as well. However others cues to distance are more effective.	of an object can be a helpful cue because objects are often found in standardized sizes.
many objects don’t come in a standard size and other objects are completely novel. Would the relative size	of a novel object the object’s size relative to other objects be a helpful cue in telling us which of the two is closer?
the size of the retinal image is an ambiguous cue. A large retinal image may be due to a distant large object or nearby small object, thus perceived distance is quite important when judging the size of an object.	of a novel object the object’s size relative to other objects be a helpful cue in telling us which of the two is closer?
ex: The Williams Ittelson and Franklin Kilpatrick study where they asked people to judge the distance of two balloons. People reported the larger balloon appeared closer.	Ballon Example
Texture gradients	refer to when you view surfaces at a slant, the texture of surfaces become denser as the distance increases. This cue is related to linear perspective. (Think railroad track)
James Gibson among the first psychologists to emphasize role of texture gradients in distance perception.	Texture gradients provide a scale by which we can measure objects, thus a nearby object that hides three texture unties is the same size as the distance object that hides three texture units.
texture units are such powerful cues to depth that even simple schematic representations are sufficient to produce a clear sense of depth.	Texture explination
atmospheric perspective	aerial perspective refers to the observation that distant objects often look blurry and bluish in contrast to nearby objects because of air between you and the distant objects which are not perfectly clear.
Shading	is a cue provided by the pattern of light and shadows. Objects may cast shadows onto other objects or it may have shadows attached to its surface.
During Halloween people place lights under their faces to distort it when teling ghost stories.	Shading helps define the shape of objects because it provides information about parts of an object that stick out or cave inward.
Height cues or elevation cues	refer to the observation that objects near the horizon appear to be farther away from us than objects far from the horizon.
Ex: Think of looking out on Lake Ponchatrain during a sunset. The sun is in the horizon and is farther away that the puffy clouds overhead which are higher in the sky.	refer to the observation that objects near the horizon appear to be farther away from us than objects far from the horizon.
Pictoral depth cues on two dimensional surfaces	pictorial depth cues were not readily apparent to ancient artists. But modern painters are aware but some are not concerned about the accurate representation of distance. Artists intent on accurately depicting a three
Trompe l’oeil	is French for “fool the eye” and some pictures are so effective they hardly seem two
Monocular depth cues involving motion. Most of your visual experience involves moving objects or moving retinas as you turn your head and move your body past objects.	is French for “fool the eye” and some pictures are so effective they hardly seem two
Motion Parallax	Objects at different distances appear to move in different directions and at different speeds. Parallax means a change in position so motion parallax is a change in the position of an object that is caused by your motion.
MP is a good source of both shape and distance information but its effectiveness depends on the pursuit of eye movements. Retinal changes due to mp would be similar for near or distant objects.	Motion Parallax pt. II
Think of driving in a car, the speed limits sign pass by more quickly than do the trees in the distance because the signs are closer to you.	Example of MP
Kinetic depth effect.	Ex: A paper clip looks flat but when it is rotated in the air it looks three dimensional.
BD Example	This can be demonstrated by holding your left thumb 6 inches from your eyes and to the left and holding the right thumb 2 feet directly ahead. BD is important because it provides the information needed to judge depth binocularly, an ability known as
Binocular disparity.	Your two eyes have slightly different views of the world whenever nearby objects are at different distances. BD refers to the different information that is registered on the two eyes.
Using a focal point, an imaginary curved line called the	horopter can be drawn to represent all the points that are equally distant from the observer. If your thumbs were positioned the same as in the BD example, imagine a curved line passing through your right thumb and continuing on either side but always 2 f
objects on the horopter and near the horopter in an areas called	panum’s area can be fused into a single image. Outside of Panum’s area, objects will typically produce double images.
objects in front of the horopter create	crossed disparity because the image crosses to the outside of the focal point on each retina.
objects behind the horopter create	uncrossed disparity
BD is primarily effective for perceiving depth in nearby objects. People more accurately judge the distance of nearby objects when they use binocular information rather than just monocular information. Whether judging distance monocularly or binocularly p	which is a cue that objects are far from us.
Using BD to create depth in pictures.	Charles Wehatstone invented the stereoscope, an instrument that has contributed greatly to out knowledge about depth perception.
A stereoscope	is a piece of equipment that presents two photographs of a scene taken from slightly different viewpoints. Typically these viewpoints are sepatated to the same extent as human eyes. (2.5 inches)
A stereoscopic picture	consists of two pictures, one for the right eye and one for the left eye. When the two pictures are seen at the same time they combine to make a three-dimensional scene.
Problem with stereoscopic pics	One problem with using stereoscopic pictures to study stereopsis is they often incorporate pictorial depth cues in addition to binocular disparity. So you could not know for sure that the sense of depth emerged solely from the binocular information.
Bela Julesz developed	random dot stereograms. Neither of the two images make sense when viewed alone, thus only stereopsis can explain the apparent depth that emerges when the two images are fused.
Class of illusory depth experiences (closely related to random dot stereograms)	When presented with a repetitive pattern like repeating wallpaper or rows of tiny dots on ceiling or floor tiles, people often teport that part of the pattern seems to pop out toward them.
Essentially the sense of depth that emerges from such stimuli arises because the visual system devises an inappropriate solution to the correspondence problem. The correspondence problem	is the difficulty our visual system can face in linking the input from the two retinas. Ordinarily, the input from the two retinas is so distinctive that the solution to the correspondence problem is relatively simple.When you look at your textbook with f
an autostereogram	is a single image that contains binocular depth information when viewed appropriately. The Magic Eye books contain these images. You visual system can solve the correspondence problem of the autostereogram in at least two ways.
Solution to autostereogram	a flat random pattern you will see if you just glance at the figure. • in another you seem to be looking through the page as though into a window.
Binocular Rivalry.	The different images presented to the two eyes are typically fused into a single image containing depth information leading Julesz to refer to the percept as cyclopean. (Think one eyed Cyclops from Greek mythology).
Eye Muscle Cues to Depth	two other potential cues to depth aren’t based on retinal information. They are based on input from the muscles that control the shape of the lens or the position of two eyes. Accomodation and convergence.
Accommodation	is the change in the shape of the lens in your eye as you focus on objects at different distances. The lens is thin to view distant objects and thick to view nearby objects. eye muscles that control lens shape respond differently to objects
Convergence	means the eyes converge, or move inward together to look at nearby objects.
Approaches to distance perception.	There are three major theoretical approaches to distance perception: the Gibsonian position, the empiricist position, and the computational approach. The Gibsonian position, the empiricist position and computational approach.
Direct Perception or Gibsonian approach	was summarized by James Cutting who said “for Gibson, information was present in the environment and needed only to be picked up”. Gibson argued the stimulus contains sufficient information to allow for correct perception.
Gibson emphasized the importance of texture gradients as a source of information about distance. Texture gradients provide a scale where we can measure objects distances from us and his emphasis is more on his general ground theory.	According to ground theory -distance perception depends on information provided by surfaces in the environment.
Either observers or objects are likely to be moving. Gibson proposed motion parallaxis part of a more general motion patter he calls motion perspective.	refers to the continuous change in the way objects look as you move about in the world.
As you directly approach a point straight ahead, objects on all sides seem to move away from that point. For example as you walk between the rows of books in the library, staring straight ahead, you should have the sense of motion perspective.	Example of Motion Perspective
Gibson emphasized the concept of affordances	actions that a person could perform with objects.
The Empiricist approach. Empircism	is a philosophical approach stating that all information is derived from sensory perceptions and experiences.
Example of Ground Theory	Looking out the window, objects do not float in the air, instead the ground serves as their background so distance can be seen more directly. Other surfaces like ceilings also provide useful information about depth.
Example of Empiricism	We are not born knowing how to perceive distance, we must acquire this skill by learning.
Bishop Berkeley outlined the empiricist position addressing the problem	the stimulus registered on the retina has only the dimensions height and width. We also see depth or distance but how can we judge the distance of an object if we cannot sense distance in and of itself?
Kinesthetic information	nonvisual information that includes all the muscular information we receive as we interact with objects.
Ex: We receive muscular information as we walk toward a distant object. Perceived distance is greater when carrying a heavy backpack.	Example of Kinesthetic informaiton
Constructivist theory	the perceiver has an internal constructive (problem-solving) process that transforms the incoming stimulus into the perception.the perceiver has an internal constructive (problem-solving) process that transforms the incoming stimulus into the perception.
Emphasizes the visual stimulus on the retina	does not provide adequate depth information, thus perception is a kind of hypothesis testing. Our visual system learns to combine other information with retinal cues to determine depth information.
Computational Approach goal	to develop a set of rules and procedures that could give rise to the perception of complex stimuli. It shares many characteristics of the constructivists approach and the direct perception approach, knowledge is crucial for perception.
Marr used research to show humans can perceive an object without specific knowledge of that object’s name or function.	Computational approach example
Module	a distinct processor that has a limited function, performs its function rapidly, has a specific neural architecture and is not accessible to central processes.
Perceiving three-dimensional objects	you perceive objects to grasp or avoid them. In other words you perceive to act.
Walter Gogel referred to the perceptual experience of space as	phenomenal geometry.
the P pathway	carries information important for binocular disparity.
All visual depth information begins	at the retina and flows through the three visual pathways M, P and K
The M pathway	conveys motion cues for depth
Though the P pathway is likely crucial for BD information, remember that input from each eye is kept separate until	primary visual cortex (V1)
Disparity-selective cells	respond to different types of disparity in input from the two eyes.
Horizontal disparities	are most important for depth perception, but vertical disparities may help locate objects in space.
Size Perception	the perception of distance and the perception of size are interrelated.
An object's distance, shape and context in which it is viewed contributes	to size perception
Perceived size = K (Retinal image size x Perceived distance)	Emmert's law formula
size constancy	means that an object seems to stay the same size despite changes in the size of the object’s retinal image. The proximal size of the object can shrink and expand, depending on how far away it is yet the distal size of the object stays the same.
visual angle	means the size of the arc that an object forms on the retina. Retinal size refers to the amount of space the object occupies on the retina. Visual angle and retinal size are closely related terms.
theoretically you could combine knowledge about an object’s distance and knowledge
Size-distance invariance hypothesis
Invariants	are aspects of perception that persist over time and space and are left unchanged by certain kinds of transformations.
Transformation Theory	involves two stages and was developed by Mark Wagner and Jack Baird. The second stage is psychological, translating the retinal image into a spatial perception.
Stage 1 of the transformation theory	The creation of the proximal stimulus on the retina, which is strictly physical process.
Muller-Lyer illusion	one of the most famous illusions in which the two horizontal lines are actually the same length.
Horizontal-vertical illusion	is similar to the top hat illusion. The horizontal and vertical lines are equal in length. Generally people perceive vertical lines as longer than horizontal lines
Ponzo illusion.	Two horizontal lines are actually the same length though the depth cues lead observers to believe differently.
Misapplied Constancy Explanation	observers interpret certain cues in the illusion as cues for maintaining size constancy. They make length judgments on the basis of size constancy and a line that looks farther away will be judged longer.
Incorrect Comparison Explanation	states the observer’s perceptions are influenced by parts of the figures that are not being judged.
Eye- movement explanation	states that illusions can be explained by differences in actual eye movements or in preparations for eye movements.
Ames room	room is an unusually shaped room that causes distortions in apparent size because it is perceived as a normally shaped room
Moon Illusion	observers report the moon at the horizon looks as much as 50% bigger than the moon at the zenith or highest position.
Misapplied Constancy approach	explains some illusions like the Ponzo.
Stage 2 of the transofrmation theory	There is room for error, for instance in perceiving the visual angle of the stimulus.
To detect the motion of a simple object,	the object must move a distance of at least 1 minute of arc.
Think of yourself at the center of a circle which is comprised of 360 degrees. one degrees is divded into 60 minutes.	Each minutes is 1/21/600 of the entire circle.
Optic Flow Field? This complex pattern of motion on our retinas is optic flow field.	As you drive along a crowded highway, if you are looking directly ahead , everything remains fairly stable on your retina. Objects in your periphery like stationary signs or slow moving cars seem to be a blur as you pass them.
direct perception theorists in the Gibsonian tradition argued that the optic flow field	is essential for determining many aspects of self-motion including the direction of movement.
observer motion combined with the motion of objects in the field of view	creates complex patterns of optical flow on our retinas
We often move in one direction while looking in another. Under such conditions, the optic flow patterns	provide us with a rich source of information to determine our direction of movement accurately. We can perceive our direction of self motion with an accuracy of 4 degrees or less.
Looming	one cue to an approaching objet is that it will take up increasingly large portions of your retina.
Biological motion	the pattern of movement of living creatures. It is real movement however most of the research doesn’t actually use images of organisms in motion. Usually a display comprised of moving points of lights is used.
Point-light display involves a minimal number of lights that are	typically assigned to joints. Point light displays contain more information than people need to extract biological motion. Observers can determine infomation from these displays including what organisms are depicted, what they are during.
Gunnar Johansson conducted the first systematic research on biological motion perception.	He connected lights to joints and immersed the people in darkness before having them move around.
Randoph Blake and aggie Shiffrar reported that point light displays enable people to	determine a person’s gender and sexual orientation at better than chance levels. People could also determine a person’s emotional state from a pointlight display especially when interacting with the display of another person.
biological motion can
Illusory Movement	observers misperceive and object’s motion.
Stroboscopic movement	is the illusion of movement produced by a rapid pattern of stimulation on different parts of the retina.
Though the path between successive presentation is ambiguous,
If the spatial separation and the timing of the two stimuli is just right,
An interval of about
An interval of about 100 milliseconds in those same conditions may result in	phi movement where the observers report they see movement yet they cannot perceive an actual object moving across the gap if the interval is longer than about 200 milliseconds.
flip books and motion pictures use stroboscopic movement	Example of stroboscopic movement II
autokinesis	occurs when a stationary light seen in total darkness appears to move. You eye muscles continually produce very small movements of your eyeballs and ordinarily when those movements occur you would be looking at the light against a rich context.
adding more lights minimizes or eliminates	the autokinetic effect. this movement is clearly illusory.
induced movement	occurs when a stationary object appears to move in one direction because its contextual frame of reference moves in the opposite direction.
self motion illusion or visually induced self motion	the perception that you are moving when you are really stationary and other objects are moving. The illusion was initially described by pioneering researchers Mach and Helmholtz.
It is possible your motion can lead you to	perceive motion when there is none.
movement aftereffects	occur when you have been looking at a continuous movement and then look at a different surface. The new surface will seem to move in the opposite direction.
corollary discharge theory	the visual system compares the movement registered on the retina with any signals the brain might have sent regarding eye movement. CD theory specifically tries to explain why we do not perceive movement during normal eye movments.
CD theory proposes that	when the brain sends a message to eye muscles it also sends a copy to a structure in thevisual system. The copy is called a corollary discharge, corollary meaning related.
first outcome in CD theory,	when looking straight ahead at a field of stationary objects, you won’t produce any corollary discharge because you aren’t telling your eyes to move. You perceive no movement.
second outcome in CD theory, when they eyes are stationary and someone moves in front of you,	the eye-head system receives no command to move so no corollary discharge is produced. The person moving across your visual field causes movement in your image
your eyes are moving. You are looking at a stationary guard in a bank. When you scan the scan by moving your eyes from right to left	you produce a corollary discharge. As you scan, the guard shifts from the left to the right of your visual field and the picture moves in a fashion consistent with expectations produced by the discharge.
Fourth CD theory outcome, With moving eyes and a moving object you track the guard who now moves from your right to the left, a corollary discharge is produced as you send the message to your muscles to track the guard.	Any sensory input from your retina consistent with the corollary discharge will be canceled out resulting in the perception of stationary objects. The moving guard falls on the same area of the retina which is inconsistent
optic flow fields	provides an important cue to depth or distance. When you drive down a road, images of objects flow across your retina at different rates
relative movement	we can tell whether we are moving or whether an object is moving by noticing the object’s movement relative to its background.
occlusion and disocculusion	moving objects show a systematic covering and uncovering of the background.
occlusion	is when your book systematically covers up the background on the left
disocculsion	is the systematic uncovering the background on the right
image size	in describing looming we noted the size of the image on your retina increases as you approach objects or they approach you
binocular cues	if you watch something come directly at you , the image moves at the same speed on both your right and left retinas.
akinetopsia	the inability to perceive movement
Example of nonbiological motion	baby chicks perfered the point light display of a walking hen to other types of motion but also preferred the motion of a walking cat to nonbiological motion.
Demonstration of a stroboscopic movement	a light flashes briefly at one location and less than a tenth of a second later another light flashes briedly at a different location. Observers report the light seems to move from the first to the second location.

4031 Test 3

Psych 4031 test 3

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