Perception

Question 1

Perception process? Bottom-Up Processing (processing begins with receptors).

Answer 1

1. Environmental stimulus (everything we would perceive)
2. Attended Stimulus (focus our attention)
3. Stimulus on Receptors
4. Transduction
5. Perception

Question 2

Top-Down Processing
(Cognitive influences).

Answer 2

1. Knowledge & Experience
2. Recognition

Question 3

Feature Integration Theory (FIT) (Objects Constructed)?

Answer 3

1. Pre-attentive stage: Identify basic units (features). Basic feature detectors in the primary visual cortex.
2. Focused Attention stage:
   Features combined so that the object is perceived. Recognize objects by comparing them to info in memory.

Question 4

FIT? Pop-Out Effect?

Answer 4

• Visual search the feature appears instantaneously irrespective of the number of distractors.
  -Curvature, tilt, line ends, movement, colour etc..
  -Properties that “pop out” = basic features.

Question 5

Pre-attentive stage (FIT)

Answer 5

Identify basic units (features)
e.g colour, orientation, movement
- Features not yet combined to form an object

Question 6

Focused Attention stage (FIT)?

Answer 6

Features combine to form an object.
Attention plays important role in combining features.

Question 7

Recognition-by-Compontents (RBC). Objects Constructed

Answer 7

Geons (volumetric primitives).
An alphabet of basic features (36 in total).
All objects are constructed of geons (e.g., lego).

Question 8

RBC View Invariance

Answer 8

RBC predicts that we should recognize an object equally well from a viewpoint as long as all geons are visible.
- Because geons can be discriminated from one another from all viewpoints (Discriminability).

Question 9

RBC- Resistance to visual nosie

Answer 9

We can recognize an object even in “noisy” situations as long as we can identify the geons.

Question 10

Gestalt Principles of Perceptual Organization?

Answer 10

1. Pragnanz: “law of good figure” or “law of simplicity.”
   E.g. Every stimulus pattern is seen in such a way that the resulting structure is as simple as possible.”

Question 11

Gestalt Principles of Perceptual Organization 2

Answer 11

2. Similarity: Lightness, hue, size, orientation etc.

Question 12

Gestalt Principles of Perceptual Organization 3

Answer 12

3. Good Continuation: Contours based on a straight or smoothly curved line are seen as belonging together.

Question 13

Gestalt Principles of Perceptual Organization 4

Answer 13

4. Proximity or Nearness: Things that are close to each other appear to be grouped together.

Question 14

Gestalt Principles of Perceptual Organization 5

Answer 14

Common Fate: Things that are moving in the same direction appear to be grouped together.

Question 15

Gestalt Principles of Perceptual Organization 6

Answer 15

Meaningfulness or Familiarity: Things are more likely to form groups if the groups appear meaningful or familiar

Question 16

Gestalt principles of Perceptual Organization
(Common Region)

Answer 16

Elements that are within the same region of space are grouped together

Question 17

Gestalt principles of Perceptual Organization
(Element Connectedness)

Answer 17

Things that are physically connected are perceived as a unit

Question 18

Gestalt principles of Perceptual Organization
(Synchrony)

Answer 18

Visual events that occur at the same time will be perceived as going together.
Occur without movement

Question 19

How do neurons become Specialized?

Answer 19

Evolution: Natural selection.
- Visual system evolved to respond best to stimuli commonly found in our environment.
- Difficult to prove

Question 20

How do neurons become Specialized? 2

Answer 20

Experience: neural selectivity shaped by experience. Monkeys trained to recognize unfamiliar objects. Humans trained to recognize greebles.

Question 21

What is Greeble Training?

Answer 21

Pre-training: measured FFA activation to faces and greebles.
Training: recognize greebles for 7 hours over 4 days
Post-training: measured FFA activation to faces and greebles.