Chapter 3-Perception Pt. 2

Question 1

Helmholtz’s Theory of Unconscious Inference

Answer 1

• 1860s
• top down theory
• some of our perceptions are the result of unconscious assumptions we make about the enviro
• we use our knowledge to inform our perceptions
• we infer much of what we know about the world

Question 2

Likelihood principle

Answer 2

• Helmholtz’s

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

Question 3

Perceptual organization

Answer 3

“old” view: structuralism
-perception involves adding up sensations

“New” view: Gestalt psychologists
-the mind groups patterns according to laws of perceptual organization

Question 4

Coglab: Apparent motion

Answer 4

• short ISI (the interstimulus interval) resulted in the two dots being presented simultaneously
• long ISI resulted in the two dots being presented alternatively
• intermediate ISI resulted in the perception of motion

Question 5

The best ISI increases with

Answer 5

Distance

Question 6

For larger separations the stimulus must ________

Answer 6

“Move” a farther distance, which presumably requires a greater length of time

Question 7

Theoretical importance of apparent motion

Answer 7

• perception involves a process of perceptual organization that requires an understanding of the relationship between the stimuli
• if perception involves simply detecting the properties of the physical world, one would expect that the observer either be able to detect the stimuli or not, but the perception is quite different: motion is observed, even though it is not a property of either of the stimuli

Question 8

Gestalt Laws of Perceptual Organization

Answer 8

• law of good continuation: lines tend to be seen following the smoothest path
• law of pragnanz: simplicity or good figure
• law of similarity: similar things appear grouped together
• law of proximity: things near each other appear grouped together
• law of common fate: things moving in the same direction appear to be grouped together

Question 9

Gestalt laws often provide ______

Answer 9

Accurate information about properties of the environment

• reflect experience
• experience is important but does not overcome perceptual principles

Gestalt laws are intrinsic

Question 10

physical regularities

Answer 10

Oblique effect
-people can perceive verticals and horizontals more easily than other orientations

Light from above assumption

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

Question 11

Semantic Regularities

Answer 11

semantic regularities are the characteristics associated with the functions carried out in different types of scenes

A scene scheme is the knowledge of what a given scene ordinarily contains (what you expect)

Question 12

Semantic regularities example

Answer 12

The gym-review results

Palmer (1975)-review results

Question 13

Bayesian interference

Answer 13

-Thomas Bayes

Ones estimate of the probability of a given outcome is influenced by two factors:

1. The prior probability (our initial belief about the probability of an outcome, hypothesis)
2. The likelihood of an observation given the outcome (hypothesis)

Question 14

Bayesian inference equation

Answer 14

P(AB)=P(A)P(B|A)=P(B)P(A|B)

P(hypothesis|observation)P(observation)= P(hypothesis)P(observation|hypothesis)

So P(hypothesis|observation) is proportional to P(hypothesis)*P(observation|hypothesis)

Review charts in notes

Question 15

Neurons and the Environment

Answer 15

Neurons become tuned to respond best to what we commonly experience

• horizontals and verticals
• experience dependent plasticity

Question 16

Neurons and the Environment example

Answer 16

Greeble

Question 17

Movement facilitates _______

Answer 17

Perception

Movement helps us perceive things in our environment more accurately than static, still images

E.g. horse

Question 18

The interaction of perception and action

Answer 18

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

Question 19

What stream

Answer 19

Identifying an object

Temporal lobe (ventral pathway)

Perception area

Question 20

Where steam

Answer 20

Identifying the objects location

Parietal lobe (dorsal pathway)

Action area

Question 21

Single dissociation

Answer 21

One function is lost, another remains

Example monkey A has damage to temporal lobe. The monkey is no longer able to identify objects (what) but can still identify locations(where)

Question 22

Do what and where rely on different mechanisms (for single dissociation)

Answer 22

Yes although they may not operate totally independent of one another

Question 23

Double dissociation

Answer 23

Required two individuals with different damage and opposite deficits

Example: monkey A with temporal lobe damage has 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 24

DF

Answer 24

Damage to temporal lobe (perception area)

If asked to match orientation of paper to mailbox she could not do it very well

If asked to put letter into mailbox she could do it pretty accurately

Has to do with the fact that her “where” or action area wasn’t damaged

Question 25

Mirror neurons

Answer 25

These neurons respond while a subject watches an action being performed in the same way as if the subject was performing the action Lacoboni (2005) found higher rate of mirroring if the subjects intention to perform the action was greater

Question 26

Lacoboni

Answer 26

-2005 mirror neurons can be influenced by different intentions Version 1: showed a hand reaching to pick up a full cup of coffee from a neatly set up table, with food on a plate Version 2: showed the same motion but the cup was on a messy table, the food was eaten and the cup was empty Version 3: showed the hand picking up an isolated cup

Question 27

Lacoboni experiment results

Answer 27

Activity signal showed version 1, 2>3 for the mirror neuron areas