Chapter 3: Perception Flashcards
Define perception
Multiple definitions:
(1) experiences resulting from simulation of the senses.
(2) the act of becoming aware of something through our senses
(3) pattern recognition: ability to detect meaningful patterns in the environment (faces, objects, etc.)
Describe what inverse projection problem is and the factors contributing to the inverse projection problem.
-Inverse projection problem is the idea that a particular image on the retina could have been caused by an infinite number of different objects and it is the task of determining which object is responsible for a particular image on the retina
-Factors contributing to inverse projection problem = objects can be hidden/blurred, view invariance
What is viewpoint invariance/view invariance?
people’s ability to recognize an object even when it’s seen from different viewpoints (this is a factor the contributes to the inverse projection problem)
Perception is built on a foundation of _______ from the ________?
information, environment
Describe what bottom-up processing is and how it works.
The sequence of events from the from the eye to the brain is called bottom-up processing
How it works:
(1) A person looking at a desk creates an imaging on the retina.
(2) The image generates electrical signals.
(3) The electrical signals are transmitted through the retina, and then to the visual receiving area of the brain.
What is top-down processing?
The knowledge we have of the environment is the basis of top-down processing. Top-down processing is…
- Processing that originates in the brain, at the “top” of the perceptual system
- Knowledge that allows people to rapidly identify objects and scenes and go beyond identification of objects and determining the story behind the scenes
Give two perceptual examples of top-down processing
Answer =
(1) Perceiving objects
- Example = Multiple personalities of a blob
- All the blobs are identical but are perceived as different objects depending on their orientation and context that they are in because of our knowledge of the kinds of objects that’re likely to be found in different types of scenes.
(2) Hearing words (in a sentence)
- A person listening that only knows English and another person that only knows Spanish can receive identical sound stimuli but experience different perceptions which means that each of these person’s experience with language is influencing their perception.
What is speech segmentation?
ability to tell when one word in a conversation ends and the next one begins. (Need to know the meaning of words to tell when one word in a conversation ends and the next starts)
What are transitional properties? Give an example.
Answer = the likelihood that one sound will follow another within a word.
Example, the words “pretty baby.” It is likely that “pre” and “ty” will be in the same word (pre-tty) but less likely that “ty” and “ba” will be in the same word (pretty-baby)
What is statistical learning?
Process of learning about transitional properties (the likelihood that one sound will follow another within a word) and about other characteristics of language
An experiment by Saffran demonstrated that infants can learn transitional probabilities. In this experiment, infants were presented with nonsense words such as “bidaku” and “padoti”. This experiment showed transitional properties of within words and between words. Which one (within or between) had higher transitional properties?
Within word, 100%
Transitional properties within word was 100% and between words was 33% which concluded that the ability to use transitional properties to segment sounds into words begins at an early age
What two types of information does perception depend on?
bottom-up (information stimulating the receptors) & top-down (information based on knowledge)
Describe Helmholtz’s Theory of Unconscious Inference, is it top-down or bottom up?
Top-down b/c this is a process in which the perceptual system applies the observer’s knowledge of the environment in order to infer what the object might be
Description = Helmholtz realized that the image on the retina is ambiguous (a particular pattern of stimulation on the retina can be caused by a large number of objects in the environment). Lead to theory of unconscious inference which states:
–> our perceptions are the result of unconscious assumptions or inferences that we make about the environment (basically, perceptions are concluded based off of unconscious assumptions)
(ex: when staring at a picture with two rectangles, we infer that it’s likely that the rectangle is covering another rectangle b/c of experiences we’ve had with similar situations in the past)
What is the likelihood principle?
States that we perceive the object that is most likely to have caused the pattern of stimuli we have received. (Preferred perceptual organization of a sensory pattern reflects the most likely object or event).
What are Gestalt principles of organization? Is this top-down or bottom-up?
Bottom up
Gestalt principles of organization
Principle of good continuation
Principle of good figure/simplicity/Pragnanz
Principle of similarity
Principle of Closure
Principle of Common Fate
Principle of Proximity
Principle of Symmetry
Principle of good continuation = when connected, result in straight or smoothly curving lines are seen as belonging together, and the lines tend to be seen in such a way as to follow the smoothest path.
Also, objects that are overlapped by other objects are perceived as continuing behind the overlapping object. (Like a rope, you know it’s all connected, and you don’t perceive the rope as separate strands, you know the rope all connects and is one long rope).
Principle of good figure/simplicity = Every stimulus pattern is seen in such a way that the resulting structure is as simple as possible
Example of this: the Olympic logo of five circles
Principle of similarity = Similar things look/appear to be grouped together
Principle of Closure = when you see an image that has missing parts, your brain will fill in the blanks and make a complete image so you can still recognize the pattern
Principle of Common Fate = Gestalt law of common fate states that humans perceive visual elements that move in the same speed and/or direction as parts of a single stimulus. A common example of this is a flock of birds. When several birds fly in the same direction, we normally assume that they belong to a single group.
Principle of Proximity = Elements that are close together will be perceived as a coherent group
Principle of Symmetry = Images that are perceived as symmetrical are experienced as belonging together
What is Bayesian Inference? Is it top-down or bottom up?
Top down
Estimate of probability of an outcome is determined by two factors
(1) the prior probability /prior (our initial belief about the probability of the outcome)
(2) likelihood of the outcome
Bayesian inference = (Prior) x (likelihood) = probability of the outcome (provides specific procedure for what might be “out there”
What are regularities in the environment? What are examples of this?
frequently occurring characteristics
Example:
Physical & Semantic
- Physical = shapes or orientations (Vertical/horizontal)
- Semantic = scenes
What did Gestalt psychologists realize about perception? What did they say it was and what did they say it was not?
Gestalt psychologists realized that perception is based on more than just the pattern of light and dark on the retina; perception is determined by specific organizing principles.
Explain according to Gestalt psychologists the role of experience in perception
experience plays a minor role. Although experience CAN influence perception, the role of experience is minor compared to the perceptual principles that are “built” into the brain systems.
Compare and contrast Gestalt psychologists and Helmholtz’s theory/theories for how we perceive
theories differ in how much experience plays a role in perception.
Gestalt = experience is minor in perception & built-in system in the brain play a larger role in perception (experience minor role in perception)
Helmholtz = our knowledge of the environment enables us to determine what’s most likely to have created the pattern on the retina (experience major role in perception)
Which of the following is NOT an example of regularities in the environment?
A. Blue associated with open sky
B. Green associated with landscapes
C. Verticals & horizontals associated with budlings
D. A boat associated with the ocean/sea
E. A cow associated with Christmas holiday
Answer = E, cows are not frequently associated with Christmas, a reindeer or Santa would make more sense.
What are the two types of regularities in the environment? What role do they play in perception? Give examples of each.
Roles they play in perception = use them to help perceive scenes and objects within scenes
(1) Physical regularities
-Regularly occurring PHYSICAL properties of the environment
-Vertical/horizontal lines are more common in the environment than angled orientations
(2) Semantic regularities
-Characteristics associated with the functions carried out in different types of scenes
-Basically, “what is going on/happening in this scene?” – interpretation of a scene
(Example: Ask people to picture a microscope. People will not just picture a microscope but will also picture other details like perhaps someone with a lab coat looking into a microscope or looking into a microscope and looking at a microscopic slide that has bacteria on it, etc.)
What is the oblique effect?
because there are more vertical/horizontal orientations compared to angled (oblique) orientations, we are able to perceive vertical/horizontal orientations easier than any other types of orientations (like oblique)
(Ex: turning)
What is the light-from-above assumption
-We usually assume that light is coming from above because light in our environment (including the sun & ceiling lights) usually comes from above
-Light coming from above & left = indicated indentation leaving shadow
-light coming from another angle = look like bump instead of indentation
-Our perception of shapes is influenced by how they are shaded, combined with the assumption that the light in coming from above.
What is scene schema?
The knowledge of what a scene contains
How can we reduce the ambiguous options when perceiving an object?
Adding a person’s prior beliefs (from Bayesian approach) reduces possible shapes that could be causing that image.
Which approach is different from the other four approaches of perception?
Gestalt approach (principles of organization are built in
Compare the four approached to perception.
Different: Gestalt approach (principles of organization are built in). Previous experience LITTLE impact on perception, more focused on brain systems/mechanism, built-in principles can override experience.
The other three approaches have in common that we use data about the environment, gathered through past experiences in perceiving, to determine what is out there:
Regularities = physical & semantic occur regularly in the environment and we use this information during perception (pervious experience)
Helmholtz = perception is based on previous experience
Bayesian = previous experience in prior & likelihood = influence perception
What is experience-dependent plasticity and what does the research on this conclude?
-Experience-dependent plasticity is the shaping of neural responding by experience, provides evidence that experience can shape the nervous system
-Research on experience-dependent plasticity shows that the brain’s functioning can be “tuned” to operate best within a specific environment
basically means that structure of the brain is changed by experience! Like how kittens that were only exposed to horizontals can still grow up to recognize horizontals thru experience
What is the purpose of perception?
to create out awareness of what is happening in the environment, as when we see objects in scenes, or when we perceive words in a conversation.
Perception and action involve which two pathways?
(1) Ventral (also known as what & perception pathway)
(2) Dorsal (also known as where, action, & how pathway)
What are mirror neurons?
neurons that respond equally when we perform an action and when we witness someone else perform the same action
(Ex: then neurons when a monkey grabs an object & when monkey watches someone else grab the same object)
Ungerleider & Mishkin (1982) studied how removing part of monkey’s brain affected its ability to identify an object and to determine the objects location. In the condition where the parietal lobes removed, what pathway was discovered?
When parietal lobes removed = monkey had difficulty solving the problem, this means that the pathway that leads to the parietal lobe is responsible for determining an objects location, so, the pathway leading from the striate cortex to the parietal lobe was called the where pathway/dorsal pathway
