Chapter 3 - Perception

Question 1

-Perception is:

Answer 1

• experience resulting from stimulation of the senses. Basic Concepts:
• perceptions can change based on added information
• involves a process like reasoning or problem solving
• perceptions occur in conjunction with actions

Question 2

-It is possible that true human perceptual processes are

Answer 2

unique to humans

-Attempts to create artificial forms of perception (machines) have been met with limited success and each time have had problems that could not be solved

Question 3

Why is it so Difficult to Design a Perceiving Machine?

-Inverse Projection Problem

Answer 3

• refers to the task of determining the object responsible for a particular image on the retina
• involves starting with the retinal image and then extending outward to the source of that image

Question 4

-Objects can be hidden or blurred

Answer 4

-people can often identify objects that are obscured and therefore incomplete, or in some cases objects that are blurry

Question 5

-Objects look different from different viewpoints

Answer 5

-viewpoint invariance

Question 6

Approaches to Understand Perception

• Direct perception theories
• bottom-up processing

Answer 6

• perception comes from stimuli in the environment (starts form the “bottom”)
• parts are identified and put together, and then recognition occurs

Question 7

• Construction perception theories

- top-down processing

Answer 7

• people actively construct perceptions using information based on expectations
• start from the “top” (brain)

Question 8

The Complexity of Perception

-Bottom-up processing

Answer 8

• perception may start with the senses
• incoming raw data
• energy registering on receptors

Question 9

Top-down processing

Answer 9

• perception may start with the brain

- person’s knowledge, experience, expectations

Question 10

Hearing Words in a Sentence

Answer 10

-when you hear words in a sentence spoken or in a foreign language, your ability to pick out or understand words based on context demonstrates top-down processing (e.g., listening to a baseball game that is broadcast in Spanish may make it easier to hear players names or certain “baseball-related” words)

Question 11

(speech segregation)

Answer 11

-the ability to tell when one-word ends, and another begins

Question 12

-transitional Probabilities

Answer 12

the likelihood that one sound will follow another within a word

Question 13

-Statistical probabilities

Answer 13

every language has transitional probabilities for different sounds, and the process of learning about transitional probabilities and about other characteristics of language

Question 14

Experiencing Pain

-Direct Pathway Model

Answer 14

• an early model that emphasized nociceptors that would send pain messages directly to the brain
• A bottom-up processing model
• more recent models have found that expectations, attentions and distraction can affect how we experience pain in a “top-down” manner
• The placebo effect
• attention, play games during bandages change

Question 15

Bottom-up Processing: Behavioral

-Recognition-by-components theory:

Answer 15

• we perceive objects be perceiving elementary features
• Geon’s: three-dimensional volumes
• objects are recognized when enough information is available to identify objects; geons

Question 16

Geons

Answer 16

• discriminability: geons can be distinguished from other geons from almost all viewpoints
• resistance to visual noise: geons can be perceived in “noisy” conditions
• distinct: 36 different geons have been identified

Question 17

Treisman’s Feature Integration theory (FIT) – COGLAB 3 – Illusory Conjunctions

Answer 17

-Visual perception and visual attention Identification of objects in the world involves two stages:

• A pre-attentive stage that automatically computes basic features
• An attentive stage that binds together the basic features to form objects Identification of objects depends on what else is also visible

-Visual search can be used for two basic purposes: First, to identify the basic features of visual perception that are proceeded pre-attentively. Second, to investigate the nature of attentive stage.

Feature integration theory (FIT)

• Pre-attentive stage
• Automatic
• No effort or attention
• Unaware of process
• Object analyzed into features

Question 18

-R.M. – Ballint’s syndrome

Answer 18

• inability to focus attention on individual objects

- high number of illusory conjunctions reported

Question 19

-Feature integration theory (FIT)

Answer 19

• mostly bottom-up processing
• top-down processing influences processing when participants are told what they would see
• top-down processing combines features with feature analysis to help one perceive things accurately

Question 20

Helmholt’s Theory of Unconscious Inference (1860)

-Top-down theory

Answer 20

• some of our perceptions are the results of unconscious assumptions we make about the environment
• we use our knowledge to inform our perceptions
• We infer much of what we know about the world

Question 21

-Likelihood principle:

Answer 21

we perceive the world in the way that is “most likely” based on our past experiences

Question 22

-unconscious inference

Answer 22

our perception is the result of unconscious assumptions or inferences about our environment

Question 23

Perceptual Organization

Answer 23

-explains the way elements are grouped together to create larger objects

Question 24

-Old-view – structuralism

Answer 24

-perception involves adding up sensations

Question 25

-“New” view – Gestalt psychologists

Answer 25

-the mind groups patterns according to laws of perceptual organization

Question 26

COGLAB 4 – Apparent Motion -Timing between the flashes was important

Answer 26

- short ISI (the interstimulus interval) - two dots were presented simultaneously - Long ISI - two dots were presented alternatively - Intermediate ISI - perception of motion - you should find that the best ISI increase with distance - the relationships between spatial separation and ISI threshold are consistent with a variety of theories that hypothesize that the visual system builds a motion percept - for larger separations, the stimulus must “move” a farther distance, which presumably requires a greater length of time

Question 27

Theoretical importance - apparent motion

Answer 27

- perception involves a process of perceptual organization that required an understanding of the relationships between stimuli - If perception involves simply detecting the properties of the physical world, one expects that the observer would either be able to detect the stimuli or not, but the percept is quite different: motion is observed, even though it is not a property of the stimuli

Question 28

Gestalt Laws of Perceptual Organization -Law of good continuation

Answer 28

-lines tend to be seen as following the smoothest path

Question 29

-Law of pragnanz (simplicity or good feature)

Answer 29

-every stimulus pattern is seen so the resulting structure is as simple as possible

Question 30

-Law of similarity

Answer 30

-similar things appear grouped together

Question 31

Perceptual Organization -Law of proximity

Answer 31

-things near to each other appear grouped together

Question 32

-Law of common fate

Answer 32

-things moving in the same direction appear to be grouped together

Question 33

-Gestalt laws often provide accurate information about

Answer 33

properties of the environment - reflect experience - experience is important but does not overcome perceptual principles - Gestalt laws are intrinsic

Question 34

Physical Regularities -Oblique effect

Answer 34

-people can perceive verticals and horizontals more easily that other orientations

Question 35

-Light-from-above assumption

Answer 35

- light comes from above - is usually the case in the environment - we perceive shadows as specific information about depth and distance

Question 36

Semantic Regularities

Answer 36

- the measuring of a given scene is related to what is happening within the scene, and semantic regularities are the characteristics associated with the functions carried out in different types of scenes - A scene schema is the knowledge of what a given scene ordinarily contains (e.g., if you think of a professor’s office, what would you expect to find/see there?) - we know that characteristics associated with the functions carried out in different types of scenes

Question 37

Bayesian Inference -Thomas Bayes (1701-1761)

Answer 37

- One’s estimate of the probability of a given outcome is influenced by 2 factors: - the prior probability (our initial belief about the probability of an outcome, hypothesis) - the likelihood of an observation given the outcome (hypothesis) - these factors set up an equation, seen below

Question 38

Neurons and the Environment

Answer 38

- some neurons respond best to things that occur regularly in the environment - neurons become tuned to respond best to what is we commonly experience

Question 39

Movement Facilitates Perception

Answer 39

- movement helps us perceive things in our environment more accurately than static, still images - for example, a horse in the distance standing still may be more difficult to discern that the horse walking across the field - walking around that same horse to see it from different angles will also facilitate accurate perception

Question 40

The Interaction of Perception and Action

Answer 40

-our actions within or upon the environment around us involve a constant stream of updating perceptions and recognition of very subtle changes

Question 41

-What stream:

Answer 41

identifying an object (ventral pathway)

Question 42

-Where stream:

Answer 42

identifying the objects location (dorsal pathway)

Question 43

Perception and Action: Using Dissociation Logic

Answer 43

- if you are tying to understand a complex system, you can logically deduce conclusions from “malfunctions” - damage to different areas of the brain cause very different deficits - we can conclude that a specific area is necessary for a specific function - Brain Ablation method allows scientists to damage specific areas of otherwise normal brains (usually in monkeys or cats) - controlled damage allows for clear conclusions to be drawn

Question 44

-perception pathway

Answer 44

path from the visual cortex to the temporal lobe (what)

Question 45

-action pathway

Answer 45

visual cortex to the parietal lobe (where)

Question 46

Single Dissociation 

Answer 46

- one function is lost, another remains - ex., monkey A has damage to temporal lobe. This monkey is no longer able to identify objects (what) but can still identify locations - therefor, what and where rely on different mechanisms, although they may operate totally independent of one another

Question 47

-Double dissociation

Answer 47

- requires two individuals with different damage and opposite deficits - ex., monkey A with temporal lobe damage ha intact “where” but impaired “what”; monkey B with parietal lobe damage has intact “what” but impaired “where” - therefore, what and where streams must have different mechanisms AND operate independently of one another

Question 48

Mirror Neurons

Answer 48

-these neurons respond while a subject watches an action being performed in the same way as if the subject was performing the action fMRI research has found evidence of a mirror neuron system in the brain -Iacoboni (2005) found higher rate of mirroring if the subject’s intention to perform the action was greater