Chapter 3: Perception Flashcards
Perception
conscious experience that results from stimulation of the senses
Inverse Projection Problem
task of determining the object that caused a particular image on the retina
Viewpoint Invariance
the ability to recognize an object seen from different viewpoints
Bottom-Up Processing
processing that starts with information received by the receptors, also called data-based processing
Top-Down Processing
processing that involves a person’s knowledge or expectations, also called knowledge-based processing
Speech Segmentation
the process of perceiving individual words within the continuous flow of the speech signal
Transitional Probabilities
in speech, the likelihood that one speech sound will follow another within a word
Statistical Learning
the process of learning about transitional probabilities and about other characteristics of language
also occurs for vision, based on learning about what types of things usually occur in the environment
Likelihood Principle
part of Helmholtz’s theory of unconscious inference that states that we perceive the object that is most likely to have caused the pattern of stimuli we have received
Unconscious Inference
Helmholtz’s idea that some of our perceptions are the result of unconscious assumptions that we make about the environment
Gestalt Psychologists
a group of psychologists who proposed principles governing perception, such as laws of organization, and a perceptual approach to problem solving involving restructuring
Apparent Movement
an illusion of movement perception that occurs when stimuli in different locations are flashed one after another with the proper timing
Principles of Perceptual Organization
rules proposed by the Gestalt psychologists to explain how small elements of a scene or display become perceptually grouped to form larger units
Principle of Good Continuation
points that when connected, result in straight or smoothly curved lines are seen as belonging together
lines tend to be seen as following the smoothest path
Principle of Simplicity (Pragnanz)
every stimulus pattern is seen in such a way that the resulting structure is as simple as possible
Principle of Similarity
similar things appear to be grouped together
Regularities in the Environment
characteristics of the environment that occur frequently
Physical Regularities
regularly occurring physical properties of the environment
Oblique Effect
the finding that vertical and horizontal orientations can be perceived more easily than other (slanted) orientations
Light-From-Above Assumption
the assumption that light is coming from above
this is a heuristic that can influence how we perceive three-dimensional objects that are illuminated
Semantic Regularities
characteristics associated with the functions carried out in different types of scenes
Scene Schema
a person’s knowledge about what is likely to be contained in a particular scene
this knowledge can help guide attention to different areas of the scene
Bayesian Influence
the idea that our estimate of the probability of an outcome is determined by the prior probability (our initial benefit) and the likelihood (the extent to which the available evidence is consistent with the outcome)
Prior Probability
a person initial belief about the probability of an outcome
Likelihood
in Bayesian inference, the extent to which the available evidence is consistent with the outcome
Theory of Natural Selection
Darwin’s theory that characteristics that enhance an animal’s ability to survive and reproduce will be passed on to future generations
Brain Ablation
a procedure in which a specific area is removed from an animal’s brain
it is usually done to determine the function of this area by assessing the effect on the animal’s behavior
Object Discrimination Problem
a problem in which the task is to remember an object based on it’s shape and choose it when presented with another object after delay
associated with research on the what processing stream
Landmark Discrimination Problem
problem in which the task is to remember an object’s location and to chose that location after delay
associated with research on the where processing stream
What Pathway
neural pathway, extending from the occipital lobe to the temporal love, that is associated with perceiving or recognizing objects, corresponds to the perception pathway (ventral)
Where Pathway
neural pathway, extending from the occipital love to the parietal lobe, that is associated with neural processing that occurs when people locate objects in space, roughly corresponds to the action pathway (dorsal)
Mirror Neurons
neurons in the premotor cortex, originally discovered in the monkey, that respond both when a monkey observes someone else (usually the experimenter) carrying out an action and when the monkey itself carries out the action, there is also evidence of mirror neurons in humans
Mirror Neuron System
a network of neurons in the brain that have mirror neuron properties
Size-Weight Illusion
when a person is presented with two similar objects that ae the same weight but different sizes, the larger one seems lighter when they are lifted together
What are the basic concepts of perception?
perceptions can change based on added information
involves a process similar to reasoning or problem solving
perceptions occur in conjunction with actions
What is the inverse projection problem?
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
Why is it so difficult to design a perceiving machine?
the inverse projection problem
objects can be hidden or blurred (people van often identify objects that are obscured and therefore incomplete, or in some cases objects that are blurry)
objects look different from different viewpoints (viewpoint invariance)
What are the direct perception theories of understanding perception?
bottom-up processing
perception comes from stimuli in the environment
parts are identified and put together, and then recognition occurs
What are constructive perception theories of understanding perception?
top-down processing
people actively construct perceptions using information based on exceptions
What is bottom-up processing?
perception may start with the senses
incoming raw data
energy registering on receptors
What is top-down processing?
perception may start with the brain
person’s knowledge, experience, expectations
How are word perceived in a sentence?
when you hear words in a sentence spoken in a foreign language, your ability to pick out or understand certain 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
What is speech segmentation?
the ability to tell when one word ends and another begins
What is the direct pathway model of experiencing pain?
an early model that emphasized nociceptors that would send pain messages directly to the brain
a bottom-up processing model
more recent modes have found that expectations, attention, and distraction van affect hoe we experience pain in a “top-down” manner (the Placebo Effect, attention, play games during bandages change)
What is the recognition-by-components theory (RBC)?
we perceive objects by perceiving elementary features
geons: three-dimensional volumes
objects are recognized when enough information is available to identify object’s geons
What are geons?
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
What are the two stages of object identification?
a pre-attentive stage that automatically computes basic features
an attentive stage that binds together the basic features to form objects
What is the procedure of the visual search Coglab?
search a visual image and respond as quickly as possible once they find a particular item, or when they are certain the item is not in the image
measure time to identify target item when the number of distractors varies
if search time is independent of the number of the distractor, it happens in the pre-attentive stage
if search time increases with the number of the distractor, it happens in the attentive stage
What is the feature integration theory (FIT)?
pre-attentive stage
automatic
no effort or attention
unaware of process
object analyzed into features
What is the Treisman and Schmidt (1982) visual search study?
participants report combination of features from different stimuli
illusory conjunctions occur because features are “free floating”
subjects were good at reporting digits
subjects made errors reporting letters and colors
more of the errors were “conjunction” errors
subjects said they saw a red letter T and a blue X
What is Balint’s syndrome?
inability to focus attention on individual objects
high number of illusory conjunctions reported
What is Helmholtz’s theory of unconscious inference?
top-down theory
some of our perceptions are the result 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
What is the likelihood principle?
we perceive the world in the way that is “most likely” based on our past experiences
What is the “old” view of perceptual organization?
structuralism
perception involves adding up sensations
What is the “new” view of perceptual organization?
Gestalt psychologists
the mind groups patterns according to laws of perceptual organization
What is the Coglab on apparent motion?
what will observers see, if two stimuli are briefly flashed in rapid succession?
the timing of the flashes was important
short ISI (the interstimulus interval), two dots were presented simultaneously
long ISI (two dots were presented alternatively)
intermediate ISI (perception of motion)
What is the theoretical importance of apparent motion?
perception involves a process of perceptual organization that required an understanding of the relationships between stimuli
if perception involves simple detecting the properties of the physical world, one would expect that the observer would either to be able to detect the stimuli or not, but the precept is quite different: motion is observed, even though it is not a property of either of the stimuli
What is the law of good continuation?
lines tend to be seen as following the smoothest path
What is the law of pragnanz (simplicity or good figure)?
every stimulus pattern is seen so the resulting structure is as simple as possible
What is the law of similarity?
similar things appear grouped together
What is the law of proximity?
things near to each other appear grouped together
What is the law of common fate?
things moving in the same direction appear to be grouped together
What are the characteristics of the Gestalt laws?
Gestalt laws often provide accurate information about properties of the environment
reflect experience
experience is important but does not overcome perceptual principles
Gestalt laws are intrinsic
What is the oblique effect?
people can perceive verticals and horizontals more easily than other orientations
What is the 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
What are semantic regularities?
the meaning of a given scene is related to what is happening with that 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 characteristics associated with the functions carried out in different types of scenes
What is Bayesian inference?
Thomas Bayes (1701-1761)
one’s estimate of the probability of a given outcome is influenced by two factors:
the prior probability (our initial belief about the probability of an outcome, hypothesis)
the likelihood of an observation given the outcome (hypothesis)
What is the relationship between neurons and the environment?
some neurons respond best to things that occur regularly in the environment
neurons becomes tuned to respond best to what we commonly experience (horizontals and verticals, experience-dependent plasticity)
How does movement facilitate perception?
movement helps us perceive things in our environment more accurately than static, still images
What is the interaction between perception and action?
our actions within or upon the environment around us involve a constant stream of updating perceptions and recognition of very subtle changes
What is the “what” stream?
identifying an object
perception
ventral
What is the “where” stream?
identifying the object’s location
occipital –> parietal
dorsal
action
How is dissociation logic used to determine the function of structures?
if you are trying to understand a complex system, you can logically deduce conclusions from “malfunction”
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
What is single dissociation?
one function is lost, another remains
example: monkey A has damage to temporal lobe, this monkey is no longer able to identify objects (what) but can still identify locations (where)
therefore, what and where rely on different mechanisms, although they may not operate totally independent of one another
What is double dissociation?
requires two individuals with different damage and opposite deficits
example: money A with temporal love damage has intact where but impaired what; monkey B with parietal love damage has intact what but impaired where
therefore, what and where streams must have different mechanisms AND operate independently of one another
What are mirror neurons?
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
Lacoboni (2005) found higher rate of mirroring if the subject’s intention to perform the action was greater
