Flashcards in Chapter Three - Perception Deck (53):
What is perception?
-experience resulting from stimulation of the senses
What are 3 basic concepts of perceptions?
1. perceptions can change based on added info
2. involves a process similar to reasoning/problem solving
3. occur in conjunction with actions
Is human perception unique to humans?
-AI has failed to match level of perception
What is the inverse projection problem?
-task of determining object responsible for a particular image on retina
-involves starting with retinal image
-then extending outward to source of that image
Why is perception so difficult for a machine? (2)
1. objects can be hidden or blurred
2. objects look different from different viewpoints (viewpoint invariance)
what is bottom-up processing?
-start at bottom of system
-environmental energy stimulates receptor
what is top-down processing?
-originates in brain
-top of perceptual system
-previous knowledge affects perception
What are direct perception theories?
-perception starts with the senses
-parts are put together
What are constructive perception theories?
-people actively construct perceptions using info based on expectations
What is an example of how top-down processing is involved in perception of objects?
-blurred blobs are identical but perceived as different objects due to orientation + context
What is speech segmentation?
-ability to tell when one word ends and another begins
How is top-down processing involved in speech?
-hearing words in a sentence in a foreign language
-ability to pick out certain words based on context
What is the direct pathway model of pain?
-early model, emphasized sensory receptors that send pain messages directly to the brain
-bottom-up processing model
What pain phenomenon challenges bottom-up processing of pain?
the placebo effect
What is Helmholtz's Theory of Unconscious Inference?
-some perceptions are result of unconscious assumptions we make about environment
-most of what we know about the world is an inference
What is the likelihood principle?
-perceive the world in way that is "most likely" based on our past experiences
What is the "Old" view of perceptual organization?
-perception involves adding up sensations
What is the new view of perceptual organization?
What do Gestalt psychologists believe?
-mind groups patterns according to laws of perceptual organization
What is apparent movement?
-movement is perceived even though nothing is moving
-whole is different than sum of its parts
What are the 3 Gestalt Laws of Perceptual Organization?
1. Law of good continuation
2. Law of pragnanz (simplicity/good figure)
3. Law of similarity
What is the law of good continuation?
-lines tend to be seen as following the smoothest path
What is the law of pragnanz?
-every stimulus pattern is seen so resulting structure is as simple as possible
What is the law of similarity?
-similar things appear grouped together
Gestalt laws often provide accurate information about properties of _________
Where do the Gestalt Laws come from?
-role of experience is minor
What do modern perceptual psychologists believe?
-perception is influenced by knowledge of regularities in environment (agreement with Helmholtz)
What are physical regularities?
regularly occurring physical properties
What are semantic regularities?
-characteristics associated with the functions carried out in different types of scenes
What is the oblique effect?
-people can perceive verticals + horizontals more easily than other orientations
What is the light-from-above assumption?
-light comes from above
-perceive shadows to inform us about depth + distance
What is a scene schema?
-knowledge of what a given scene ordinarily contains
EX: professor's office
What is perception according to the inferential approach?
-given an image (input) + the knowledge about regularities of physical world
-pick most probably interpretation of image
What is Bayesian Inference?
-one's estimate of the probability of a given outcome is influenced by 2 factors:
1. prior probability
2. likelihood of a given outcome
What are the 4 approaches to perception?
1. Helmholtz's unconscious inference
2. Gestalt Laws of organization
3. Regularities in the environment
4. Bayesian inference
Which of the 4 approaches to perception are bottom-up? Top-down?
Gestalt Laws of Organization
Helmholtz's unconscious inference
regularities in environment
What do modern psychologists claim about the Gestalt Laws?
laws could have also been created by experience
What happens to neurons over time?
-become tuned to respond best to what we commonly experience
Why is it beneficial that neurons be atuned to stimuli over time?
-neurons can be trained to respond to specific stimuli
What is experience-dependent plasticity?
mechanism through which the structure of the brain is changed by experience
How did Blakemore and Graham Cooper demonstrate plasticity?
-raised kittens in space in which they only saw vertical black + white stripes on walls
-visual cortex had been reshaped
experience-dependent plasticity plays a role in activation of the _________
fusiform face area (FFA)
What happened after "Greeble recognition?"
-FFA fired as much for Greebles as it did for faces
_____ helps us perceive things in our environment more accurately than static images
What are the 2 processing streams?
-what stream: identifying an object
-where stream: identifying object's location
What two methods were used to discern the two processing streams?
1. brain ablation
How did Ungerleider and Mishkin study about the what and where pathway?
-studied how removing part of a monkey's brain affected its ability to identify an object + determine its location
What is object discrimination?
-monkey shown object
-must pick correct object
What is landmark discrimination?
-cylinder indicates which side monkey's food is on
The temporal lobe controls which pathway?
The occipital lobe controls which pathway?
What did Milner and Goodale find?
-studied 34 year old woman with damage to temporal lobe
-asked to rotate card
-asked to mail a card