Perception Flashcards
What is perception?
-the process of recognizing, organizing and interpreting information from senses
What is the difference between perception and sensation?
-sensation is objective and perception is subjective
What is the inverse projection problem and why is it hard for computers to observe similar objects?
-they confuse objects that share features (think of like a tennis ball and a circular plate)
-the human brain can go back into memories and figure out what it is
What is an example of a challenge of object perception?
-three shapes at different angles that are all different shapes but look like the same shape because of the way they are angled and the depth they are at. Humans can figure out these are different shapes but AI struggles to
Why do AI struggle with hidden or blurred images? Think of a hidden pair of scissors, we know what they are but the AI program may struggle. Or blurred photos of celebrities.
-because we can go into our memory but a computer struggles with that
What is viewpoint invariance?
-the ability to recognize an object from different viewpoints
What is bottom-up processing?
-starts with the sensory receptors and then works up to the brain to identify the object/scene being perceived
What is top-down processing?
-based on the knowledge we have
What are the three bottom-up approaches we discuss? (3)
-template matching theory
-feature approaches (Selfridge)
-recognition by components
What is template matching theory? Example. (2)
-we compare a stimulus with a set of templates we have in our memory and identify the object when a match is actually made
Example: the barcodes on items at the grocery template match the bar codes in the system which brings up the price
What is a huge downfall of template matching theory for humans?
-humans are able to interpret things that are scratched out or obscured or in different people’s handwriting (we essentially don’t do this)
What is the feature approaches pandemonium model by Selfridge?
-feature by feature analysis that allows for recognition, pattern recognition with “demons” processing visual information in stages.
What are the limits of the feature approaches pandemonium model?
-cannot breakdown extremely complex things or very simple things
What is recognition-by-components theory by Biederman?
-the way we perceive and recognize objects is by breaking them down into these individual 3D shapes he called geons
How many geons did Beiderman say we have?
-36
What are the strengths of the recognition-by-components theory? (4)
-viewpoint invariance
-can recognize objects despite visual noise
-can produce 306 billion objects
-the ability to recognize geons develops early in life
What are the weaknesses of the recognition- by-components theory? (2)
-can’t take a 2D photo of an object and work backward to describe a 3D object
-based solely on geons it is hard to distinguish between objects
What are the three top-down approaches? (3)
-Helmhotz’s theory of unconscious inference
-getalt principles of organization
-environmental regularities
What is speech segmentation?
-knowing when a word begins and ends in speech based on previous experience with the language, think about how you struggle to hear the separate words in german
What is Helmholtz’s theory of unconscious inference?
-when we are identifying objects, often we do it based on these unconscious assumptions that we make because of our experience, think about the blue and red rectangle example in class
What is the likelihood principle?
-we perceive the world in the way that is “most likely” based on our past experiences
What is Gestalt’s principles of organization? What is an example of this? (2)
-we view things as a whole, not their parts
-apparent motion, with the two dots that flash back and forth
What is the law of good continuation?
-lines tend to be seen as following the smoothest path
What is the law of good figure?
-we tend to interpret things in the simplest way possible, like the olympic rings
What is the law of familiarity or meaningfulness?
-things are more likely to form groups if the groups appear familiar or meaningful
What is the law of similarity?
-similar things appear grouped together
What is the law of proximity?
-things near each other appear grouped together
What is the law of common fate?
-things in the same direction appear to be grouped together
What are regularities in the environment?
-things that occur frequently in our environment thus helps us to recognize them faster
What are the two types of regularities in the environment?
-physical and semantic
What is a physical regularity?
-regularly occurring physical properties of the environment, think about how rare slanted objects in our space are
What are semantic regularities?
-the meaning of a scene, like if a classroom doesn’t look like a classroom
What is the light from above heuristic?
-we perceive depth differently depending on where the light is coming from, think of church pew information
What is a scene schema?
-the knowledge of what a given scene usually contains (like what you would expect to see in a doctors office)
What is experience dependent plasticity? What is an example of this? (2)
-response properties of neurons are shaped by learning
-eye cells that respond more to vertical and horizontal lines because those are more in our environment
What did the Greeble experiment do and show? (2)
-examine the fusiform face area where they did MRI while people looked at greebles before and after they were experts in them
-demonstrated that the fusiform face area (FFA) is not necessarily a specialized face recognition area, but rather an area involved in recognizing objects of expertise.
What is amblyopia?
-weak muscles don’t allow the eyes to move in synchrony so one eye becomes stronger than the other
What is a brain ablation?
-destroying a particular area of the brain to study brain function
What is object discrimination?
-the ability to recognize and differentiate between different objects based on their features, such as shape, color, or texture.
The ventral stream or the ‘what’ pathway processes which information?
-object discrimination
What is landmark discrimination?
-the ability to recognize and use spatial cues or landmarks to navigate or make decisions about movement or location.
The dorsal stream or where pathway processes which information?
-landmark discrimination
Damage to the ventral stream causes what? What does this look like? (2)
-visual agnosia
-an inability to recognize objects despite having normal vision.
Damage to the dorsal stream causes what? What does this look like?
-optic ataxia
-a person struggles to guide their movements based on visual input. They may be unable to reach for an object accurately, even though they can see it.
What are mirror neuron’s?
-a special type of brain cell that activates both when we perform an action and when we observe someone else performing the same action. Essentially, they allow us to “mirror” the actions or emotions of others
What is prosopagnosia?
-they have damage to the FFA area and cannot recognize faces
What is hallucinogen persisting perception disorder?
-a condition where people experience recurring visual disturbances or other sensory perceptions after using hallucinogenic drugs
What is akinetopsia?
-the inability to perceive motion
