Task 5 - From visual shapes to objects

Question 1

What are the three stages of visual processing?

Answer 1

Low-level (early) vision – Extracts basic features (e.g., dots, lines).
Mid-level (middle) vision – Groups features into objects.
High-level vision – Recognizes objects and understands scenes.

Question 2

What is perceptual organization?

Answer 2

The process by which elements in the visual field are grouped into objects or segregated from one another.

Question 3

What is holistic processing?

Answer 3

Recognizing an object as a whole rather than as separate parts (e.g., face recognition).

Question 4

What is the Recognition-by-Components (RBC) theory?

Answer 4

Objects are recognized by their geometric components called geons.

Question 5

What are geons?

Answer 5

Basic 3D shapes (e.g., cylinders, cubes) that can be combined to form any object.

Question 6

What are some limitations of RBC theory?

Answer 6

Not fully viewpoint-invariant – Some rotations make objects harder to recognize.
No complete set of geons proposed – Unclear how many are needed.

Question 7

What are illusory contours?

Answer 7

Contours perceived even when no physical edges exist (e.g., Kanizsa square).

Question 8

Which brain area responds to illusory contours?

Answer 8

V2 (but not V1).

Question 9

What is Gestalt psychology?

Answer 9

The idea that perception is more than the sum of its parts

Question 10

What are Gestalt grouping principles?

Answer 10

Good continuation – We see continuous lines instead of abrupt changes.
Closure – We prefer closed shapes over open ones.
Similarity – Objects that look alike group together.
Proximity – Objects near each other group together.
Common fate – Objects moving together are grouped together.

Question 11

What is the inverse projection problem?

Answer 11

Any 2D image on the retina can come from multiple real-world objects.

Question 12

What is an ambiguous figure?

Answer 12

A visual stimulus that allows for multiple interpretations (e.g., Necker cube).

Question 13

What is Helmholtz’s theory of unconscious inference?

Answer 13

The brain unconsciously guesses the most likely cause of an image.

Question 14

What is an accidental viewpoint?

Answer 14

A viewing position that misaligns objects, creating false patterns.

Question 15

What is figure-ground assignment?

Answer 15

Determining which part of an image is object (figure) and which is background (ground).

Question 16

What are cues for figure-ground perception?

Answer 16

Surroundedness – The smaller region is seen as figure.
Size – Smaller objects tend to be figures.
Symmetry – Symmetrical shapes are seen as figures.
Parallelism – Parallel contours suggest a figure.

Question 17

What is a scene?

Answer 17

A view of the real world with a background and multiple objects.

Question 18

What is the gist of a scene?

Answer 18

A general understanding of a scene, processed in less than 1 second.

Question 19

What are physical regularities?

Answer 19

Common patterns in the environment (e.g., most edges are vertical or horizontal).

Question 20

What is the light-from-above assumption?

Answer 20

We assume light comes from above, affecting shadow perception.

Question 21

What are semantic regularities?

Answer 21

Expectations about what objects belong in a scene (e.g., kitchens contain stoves).

Question 22

What is the extrastriate cortex?

Answer 22

Visual areas beyond V1, including V2, V3, V4, and V5 (MT)

Question 23

What are the two visual pathways?

Answer 23

Ventral (What) Pathway – Identifies objects, runs to the temporal lobe.
Dorsal (How) Pathway – Guides actions, runs to the parietal lobe

Question 24

What is the inferotemporal (IT) cortex?

Answer 24

A brain area that contains neurons responding to specific stimuli, like faces and objects.

Question 25

How does object recognition involve memory?

Answer 25

The IT cortex connects with the hippocampus, linking perception to memory.

Question 26

What is the fusiform face area (FFA)?

Answer 26

A brain region specialized for face recognition.

Question 27

What is the lateral occipital cortex (LOC)?

Answer 27

A region that responds to objects, but not to scrambled textures.

Question 28

What is the parahippocampal place area (PPA)?

Answer 28

A brain region that responds to scenes (e.g., landscapes, buildings).

Question 29

What is the extrastriate body area (EBA)?

Answer 29

A brain region that processes body parts (but not faces).

Question 30

What is the visual word form area (VWFA)?

Answer 30

A brain region that responds strongly to written words.

Question 31

What is pure alexia?

Answer 31

Inability to read words, despite being able to speak and write.

Question 32

What is the neuronal recycling hypothesis?

Answer 32

New cultural skills (like reading) reuse old brain areas that evolved for other purposes.

Question 33

How does literacy change the brain?

Answer 33

Increases LOC activity for all objects. Enhances sensitivity to horizontal lines. Strengthens V1 connections for contour processing. Reduces the VWFA’s response to faces (faces shift to the right hemisphere)

Question 34

What is mirror invariance?

Answer 34

The ability to recognize mirror-flipped images as the same (e.g., a chair facing left vs. right).

Question 35

How does literacy affect mirror invariance?

Answer 35

Learning to read reduces mirror invariance, making it harder to see "b" and "d" as identical.

Question 36

What is the principle of common region?

Answer 36

Elements within the same bounded area are perceived as a group.

Question 37

What is the principle of uniform connectedness?

Answer 37

Connected elements with the same visual properties (color, texture, motion) are perceived as a single unit.

Question 38

What is parallelism in visual perception?

Answer 38

Parallel contours are more likely to be grouped together.

Question 39

What is the principle of symmetry?

Answer 39

Symmetrical regions are more likely to be seen as belonging together

Question 40

What is the principle of Pragnanz (Good Figure/Simplicity)?

Answer 40

The simplest, most stable interpretation is the one we perceive.

Question 41

What is the principle of common fate?

Answer 41

Objects moving in the same direction are grouped together (e.g., flock of birds).

Question 42

What is viewpoint invariance?

Answer 42

The ability to recognize an object from different angles.

Question 43

What are the advantages of viewpoint invariance?

Answer 43

It allows us to quickly recognize objects in different orientations.

Question 44

What are the disadvantages of viewpoint invariance?

Answer 44

Some rotations make object recognition harder (e.g., upside-down faces).

Question 45

How does the brain process viewpoint invariance?

Answer 45

The inferotemporal (IT) cortex helps recognize objects despite changes in viewpoint.

Question 46

What is an example of an ambiguous figure?

Answer 46

The Rubin vase/face illusion – it can be seen as either a vase or two faces.

Question 47

What is the role of the "visual committee" in perception?

Answer 47

Different brain regions "debate" possible interpretations, leading to a final perception.

Question 48

What happens when the visual system fails to resolve ambiguity?

Answer 48

It leads to bi-stable perception, where the image flips between two interpretations (e.g., Necker cube).

Question 49

What are global image features?

Answer 49

Large-scale properties (e.g., openness, roughness) that help us quickly understand a scene.

Question 50

How does the brain process scene gist so quickly?

Answer 50

It uses statistical regularities and past experience to make rapid guesses.

Question 51

What is a scene schema?

Answer 51

Knowledge about what objects belong in a scene (e.g., a stove in a kitchen).

Question 52

What is the difference between physical and semantic regularities?

Answer 52

Physical regularities – common patterns in nature (e.g., vertical & horizontal lines). Semantic regularities – expectations based on typical scene functions (e.g., eating in a dining room).

Question 53

What is relatability in visual perception?

Answer 53

The likelihood that two segments belong to the same object, based on how smoothly they connect

Question 54

What are the three types of junctions that help with occlusion perception?

Answer 54

T-junctions – Indicate one surface is blocking another. Y-junctions – Typically occur at corners of objects. Arrow junctions – Suggest 3D corners of solid objects.

Question 55

What are nonaccidental features?

Answer 55

Features that are unlikely to be a coincidence (e.g., straight edges on a cube).

Question 56

What is the function of the parahippocampal place area (PPA)?

Answer 56

It specializes in processing scenes and places.

Question 57

What is the function of the extrastriate body area (EBA)?

Answer 57

It processes bodies and body parts (excluding faces).