Perception

Question 1

Sensation

Answer 1

• Process of encoding energy (light, thermal, kinetic) or chemicals in the environment in terms of neural signals
• basic experience elicited by a simple stimulus
• physical experience

Question 2

Perception

Answer 2

• organization and interpretation of neural signals (makes them meaningful)
• complex experiences produced by integrating sensations
• identifying the stimulus

Question 3

Bottom-up (data-driven) processing

Answer 3

Low level stimulus data from receptors is processed (can combine to form patterns)
→ does not involve what is learnt from the perceptual world

Question 4

Top-down (conceptually driven) processing

Answer 4

Higher level cognitive processes (memories, beliefs, expectations) affect interpretations of stimulus gathered by the senses
→ conceptual knowledge of context influences perception

Question 5

Gestalt psychology

Answer 5

• movement could be produced by a succession of stationary stimuli
• the whole is different than the sum of its parts
  Pros: holistic approach
  Cons: not good for predictions, not good at explanations, vague definitions

Question 6

Figure-ground segregation

Answer 6

Figures:
- appear to be in front
- are smaller
- have well-defined shape
- are meaningful
- have more detail
- differ from background in brightness

Question 7

Laws of perceptual organization

Answer 7

• Proximity / nearness: things close to eachother tend to be grouped together
• similarity: similar things tend to be grouped together
• good continuation: points that if connected would result in straight or smoothly curving lines (tend to belong together)
• closure: a space enclosed by a contour tends to appear as a figure
• common fate: things that are moving in the same direction tend to be grouped together
• meaningfulness / familiarity: things that are meaningful or familiar tend to form groups

Question 8

Law of Prägnanz

Answer 8

Every stimulus pattern is seen in a way such that the resulting structure is as simple as possible

Question 9

Recognition

Answer 9

Perceiving something as previously encountered

Question 10

Identification

Answer 10

Naming or classifying an object

Question 11

Template-matching models

Answer 11

• Represented as holistic, unanalyzed unit (template)
• input pattern compared to stored representations
• stimulus categorized by exact match

Pros: successfully used by machines (ie. Barcodes)
Cons: intolerant to variations, too many templates, cannot handle context, cannot handle novel stimuli

Question 12

Distinctive-features models

Answer 12

Pandemonium
Stage 1: image demon (gets sensory input)
Stage 2: feature demons (analyze input in terms of features)
Stage 3: cognitive demons (determine which group of features are present)
Stage 4: decision demon (identifies pattern by listening to the cognitive demon shouting loudest)

Pros: visual feature detectors, can identity wide range of stimuli
Cons: does not define feature, cannot handle Gestalt principles, cannot handle context

Question 13

Recognition by components

Answer 13

• Visual scene can be decomposed into a constant set of basic elements
  → geons: can be modified yet remain identifiable
• principle of componential recovery: if an object’s geons can be determined, it can be identified even if the object is partially obscured

Pros: has well-defined features, can handle variation / novelty
Cons: cannot handle context, may be too broad

Question 14

Apperceptive agnosia (visual form / space agnosia)

Answer 14

• Failure to form a holistic percent (perception of whole objects)
• cannot identify, discriminate, or copy complex visual forms
• can grasp objects they cannot identify

Question 15

Associative agnosiah

Answer 15

• Deficit in associating patterns with meaning (recognition without meaning)
• cannot draw from memory
• can copy and draw pictures but cannot identify them
• can use other senses

Question 16

Category specific (semantic) agnosia

Answer 16

• Inability to identify living or nonliving objects

Question 17

Bálint’s syndrome

Answer 17

• Inability to perceive more than one aspect of a visual stimulus, or integrate details into a coherent whole
• can identify individual objects but cannot locate them or reach for them

Question 18

“What” pathway

Answer 18

• Object recognition and identification
• from occipital lobe to temporal lobe (ventral pathway)

Question 19

“Where” pathway

Answer 19

• Involved in locating objects, motion, spatial relationships, depth
• from occipital lobe to parietal lobe (dorsal pathway)