Psyc 2300 Midterm 2

Front 1

Field of View (Modes of Attention)

Back 1

- Horizontal field: 90 degrees on both sides = 180 degrees

- Vertical field: slightly less (occluded by forehead/cheek bones)

Lecture 9/29

Front 2

Binocular/Monocular Vision

Back 2

Binocular vision: both eyes can see

- Predators have more, for better acuity

Monocular vision: only one eye can see

- Prey have more, for better FOV

Lecture 9/29

Front 3

Foveated Vision

Back 3

Good detail where looking, poor detail in periphery.

Rare trait in animals.

Lecture 9/29

Front 4

Point Vision

Back 4

Uniform density of photoreceptors. Each area of vision can see same detail.

Lecture 9/29

Front 5

Two Fovea

Back 5

One is for central vision, another is the temporal area for tracking things on the ground. Typical of birds of prey and hummingbirds.

Lecture 9/29

Front 6

Visual Streak

Back 6

Typical in dogs and cats. Have an elongated streak on the retina that has a high density of photoreceptors.

Lecture 9/29

Front 7

Saccades (Mode of Attention)

Back 7

Rapid, ballistic eye movements.

- Takes 30ms

- 3x per second

- Occur between fixations (300ms)

- Saccadic suppression causes temporary blindness during them

- 10% of vision time

Lecture 9/29

Front 8

Smooth Pursuit Eye Movements

Back 8

Only primates have this capability. Must fixate on a moving target or else you make saccades.

Primates have them because we have hands so we can manipulate objects close to our face.

Lecture 9/29

Front 9

Visual Search

Back 9

Find something in an array of objects.

Two types:

- Effortless

- Effortful

Lecture 9/29

Front 10

Effortless Search

Back 10

# of distractors doesn't matter. Target has a unique feature that makes it stand out from the rest.

Preattentive processing is all that is needed.

Lecture 9/29

Front 11

Effortful Search

Back 11

Reaction time increases with # of distractors. Must focus attention.

Lecture 9/29

Front 12

Primitive Features

Back 12

Features that humans attend preattentively. Must be unique to target for effortless search.

- lines vs. curves

- angles

- color

- motion

Lecture 9/29

Front 13

Parts are transposable (Perceptual Organization)

Back 13

For a scene, parts don't matter, but the relationships between them do.

Lecture 10/1

Front 14

Laws of Perceptual Organization (5)

Back 14

1. Law of Figure/Ground

2. Law of Grouping

3. Law of Good Gestalts

4. Law of Perceiving Whole Objects

5. Law of Perceiving Constant Properties

Front 15

Law of Figure/Ground (Law of Perceptual Organization)

Back 15

Edges have ambiguity (which object does an edge belong to?)

Decisions

1. Edge belongingness

2. edge defines shape of figure

3. depth order (what is in front)

4. Background extension (extension behind figure)

Lecture 10/1

Front 16

Laws of Grouping (Law of Perceptual Organization)

Back 16

- Proximity

- Similarity

- Good continuation: a contour will appear to be connected if occluded and angles are reasonable

- Closure

- Common Fate

Lecture 10/1

Front 17

Law of Proximity

Back 17

Things that are close together are grouped together

Front 18

Law of Similarity

Back 18

Things are grouped by similarity (duh)

Front 19

Grouping by good continuation

Back 19

If a contour is continous, you'll percieve it to be one thing. Something is well-aligned if it has good continuation. Cannot have more than 1 inflection.

Front 20

Grouping by closure

Back 20

If there's good continuation, the brain will complete the contour. A subjective contour is perceived but not really there.

- Modal: not occluded, seen

- Amodal: occluded, not seen

Front 21

Grouping by common fate

Back 21

If it moves together, its' grouped together

Front 22

Law of Good Gestalts (Law of Perceptual Organization)

Back 22

"minimum principle"

The default is symmetry and regularity

Front 23

Law of Perceiving Whole Object (Law of Perceptual Organization)

Back 23

you perceive occluded objects as a whole

Front 24

Law of Perceiving Constant Properties (Law of Perceptual Organization)

Back 24

(Nothing in notes)

Guess: Constant texture gradient, etc.

Front 25

Inverse projection problem

Back 25

There are infinite possible objects that could produce the same visual angle

Front 26

Depth cues

Back 26

sources of information used to compute depth

- Primary: eyes

- Secondary: pictorial

- Motion-based: objects & self

Front 27

Primary Depth Cues

Back 27

- Accommodation

- Convergence

- Stereo

Front 28

Accommodation (Depth Cue)

Back 28

changing the shape of the lens

- thick: light bent a lot

- thin: light bent little

good for close objects, at arm's length but not further

Front 29

Convergence (Depth Cue)

Back 29

verging the eye on a target

near object=larger angle

far object= smaller angle since you're looking out

good for things that are close

***Include picture of angles

Front 30

Stereo (Depth Cue)

Back 30

depth perception based on image disparity

- information: retinal disparity, different images projected at different locations

- process: stereopsis, computing depth relations

provides some information after 20 ft. but not much

Front 31

Secondary Cues (Depth Cue)

Back 31

1. Perspective

2. Familiarity (size)

3. Shading

4. Occlusion

Front 32

Perspective (Pictorial Clues(?)) (Depth Cue)

Back 32

1. linear perspective

2. horizon ratio

3. texture gradient

4. height in plane

Front 33

Linear Perspective (Pictorial Cue)

Back 33

all parallel lines converge on the horizon at the vanishing point

Front 34

Horizon Ratio (Pictorial Cue)

Back 34

has to be objects on flat ground

- size of things relative to eye height

- Ground must be flat for this to work

Front 35

Texture Gradient (Pictorial Cue)

Back 35

units of texture more dense at the horizon

- objects of equal size have the same texture at the base

- can scale objects by looking at feet

Front 36

Height in Plane (Pictorial Cue)

Back 36

higher in plane = higher angle of elevation

Front 37

Familiarity (size)

Back 37

- Familiar size scales the space an object is in

- People trump everything else when comparing size

Front 38

Shading

Back 38

Assumption: light comes from above.

- "above" is relative to retina

Front 39

Occlusion

Back 39

Things that are closer cover up things behind.

- Determines depth order but not depth magnitude.

Front 40

Motion Cues

Back 40

- Kinetic Depth Effect (Structure from motion)

- Motion Parallax

Front 41

Kinetic Depth Effect (Motion cue)

Back 41

A solid object rotated gives depth info and defines shape.

- Must be rotated on any axis except line of sight.

- Solves inverse projection problem

Front 42

Motion Parallex (Motion Cue)

Back 42

The closer something is, the faster it appears to move.

- Fixation causes things to move at a rate proportional to how far it is from point of fixation (the closer the less it moves)

Front 43

Properties Revealed in Motion

Back 43

1. Surface Segregation

2. 3D Form

- Rigid

- Hierarchical

Front 44

Surface Segregation

Back 44

Solves figure/ground problem when object moves on background.

- Dynamic Occlusion: When a surface moves over another, you can't help noticing the revealing/covering of texture.

- Most powerful cue

- M-Cells detect this motion

Front 45

Hierarchical 3D Form

Back 45

Consists of 3 types of motion:

- Absolute

- Relative

- Common

Front 46

Absolute Motion

Back 46

Movement of individual components

Front 47

Relative Motion

Back 47

Movements relative to one another.

Front 48

Common Motion

Back 48

Motion as a unit.

Front 49

Focus of Expansion

Back 49

How we are able to tell where we are going. Texture moves away from stationary point of focus.

Measured by:

- Time to Contact

- Time to Passage

Front 50

Time to Contact

Back 50

Used to determine how long until you collide with something.

Visual angle divided by change in angle per second. (tau)

Front 51

Time to Passage

Back 51

Used to determine how long until something passes you.

Visual angle divided by change in angle per second. (tau)

Front 52

Linear Optical Trajectory Heuristic

Back 52

Position yourself so that trajectory is linear so that you will intercept the path of the airborne object.

Not optimal because it causes a curved travel path, and doesn't specify where the landing spot is. Also doesn't provide environmental info.

Front 53

Perceptual Development: Color

Back 53

- 2 cones (not blue) for newborn

- 3 Cones at 3 months

Front 54

Perceptual Development: Acuity

Back 54

- 20/500 at birth

- 20/40 at 7 months

Babies and adults differ in:

- Photoreceptor shape

- Density of photoreceptors

- Cell connectivity

Babies have short, wide receptors that are less dense in the macula, and less connected than that of adults.

Front 55

Cell Migration

Back 55

The process in which photoreceptor cells in infant eyes move toward central vision.