Chapter 3 - Perception Flashcards
Perception
- experiences resulting from the stimulation of the senses
Inverse projection problem
- task of determining the object that caused a particular image on the retina
- starting with the retinal image and extending rays out from the eye
- happens naturally
viewpoint invariance
- the ability to recognize an object seen from different viewpoints
- knowing it’s the same object even though your angle has changed
2 types of systems
bottom-up processing
1) looking at something creates an image on the retina
2) image generates electrical signals that are transmitted through the retina and then to the visual receiving area of the brain
- starts at the bottom when environmental energy stimulates the receptors
2 types of systems
top-down processing
- knowledge we have of the environment
- originates in the brain at the “top” of the perceptual system
- enables us to rapidly identify objects
- filling in the blanks because of what we expect to see (context cues)
top-down
speech segmentation
- the ability to tell when one word in a conversation ends and the next one begins
- why we can’t make sense of other languages (words realistically blend together)
transitional probabilities
- the likelihood that one sound will follow another within a word
statistical learning
- the process of learning about transitional probabilities and about other characteristics of language
Helmholtz
likelihood principle
- we perceive the object that is most likley to have caused the pattern of stimuli we have received
unconscious inference
describes likelihood principle
- our perceptions are the result of unconscious assumptions that we make about the environment
Gestalt princples
apparent movement
- although movement is perceived, nothing is actually moving
What idea did the Gestalt psychologists reject?
- that perceptions are formed by “adding up” sensations
Gestalt
What 2 conclusions did Wertheimer come to regarding apparent movement?
- cannot be explained by sensations because there is nothing between the flashing lights
- the whole is different than the sum of it’s parts
What do the principles of perceptual organization explain?
- the way elements are grouped together to create larger objects
Gestalt principles
Good continuation
- points that, when connected, result in straight or smoothly curving lines are seen as belonging together
- objects that overlap are seen as continuing behind
- ex. shoelaces (2 separate strings that we see as a whole)
Gestalt principles
Pragnaz (principle of good figure, simplicity)
- every stimulus pattern is seen in such a way that the resulting structure is as simple as possible
Gestalt principles
Similarity
- similar things appear to be grouped together
regularities in the environment
- characteristics of the environment that occur frequently (ex. blue = open sky)
- provide information we can use to resolve ambiguities
Physical regularities
- regularly occuring physical properties (ex. buildings are vertical just like most things in nature (trees))
physical regularities
oblique effect
- people perceive horizontals and verticals more easily than other orientations
physical regularities
light-from-above assumption
- we usually assume that light is coming from above because that is how it normally is in our environment
Semantic regularities
- “semantics” refers to the meanings of words or sentences
- when applied to perception, semantics refers to the meaning of a scene
- characteristics associated with the functions carried out in different types of scenes (context)
- ex. when asked to imagine an office, we know we are thinking of an office because of the things we imagine are in that room (chair, desk, paperwork, etc.)
semantic regularities
scene schema
- our visualizations contain information based on our knowledge of different kinds of scenes
- expectations created by scene schemas contribute to our ability to perceive objects and scenes
Bayesian inference
- the idea that our estimate of the probability of an outcome is determined by the prior probability and the likelihood
Bayesian inference
prior probability (prior)
- our initial belief about the probability of an outcome
bayesian inference
likelihood of an outcome
- the extent to which the available evidence is consistent with the outcome
- additional information added to our initial belief
what are the 4 conceptions of object perception?
1) Helmholtz’s unconsious inference
2) the Gestalt principles
3) regularities in the environment
4) Bayesian inference
How are the Gestalt principles different from the other 3 approaches?
- emphasizes the idea that the principles of organization are built in
the other 3 say we use data about the environment and past experiences to determine what is out there
theory of natural selection?
why are there more neurons that respond to horizontals and verticals?
- characteristics that enhance an animal’s ability to survive, and therefore reproduce, will be passed on to future generation
brain ablation
- removing part of the brain to determine its function
object discrimination problem
landmark discrimination problem
‘what’ pathway (ventral)
- neural pathway, extending from the occipital lobe to the temporal lobe, that is associated with perceiving or recognizing objects
- corresponds to the perception pathway
‘where’ pathway (dorsal)
- neural pathway, extending from the occipital lobe to the parietal lobe, that is associated with neural processing that occurs when people locate objects in space
- roughly corresponds to the action pathway
perception pathway
- neural pathway, extending from the occipital lobe to the temporal lobe, that is associated with perceiving and recognizing objects
- corresponds to the what pathway
action pathway
- neural pathway, extending from the occipital lobe to the parietal lobe, that is associated with neural processing that occurs when people take action
- corresponds to the where pathway
mirror neurons
- neurons that respond both when a monkey observes someone else grasping an object such as food on a tray and when the monkey itself grasps the food
mirror neuron system
- a network of neurons in the brain that have mirror neuron properties
