Lecture 2 (Ch. 3 Perception) Flashcards
What’s the difference between sensation and perception?
Sensation is the reception of data from the sense.
Perception is our experience based on these sensations.
What are the characteristics of perception?
Personal - top-down processing allows all of us to have different perceptions
Active - process similar to reasoning or problem solving
Changeable - can be altered based on new knowledge, expectations, or context
What is the inherent complexity of perception?
Inverse projection problem - the same perception can be caused by many different stimuli
There are distortions in our perceptions.
And there is viewpoint invariance (ability to recognize same object from different views).
Describe the bottom-up process of vision?
Feature analysis - we detect certain features (ex: horizontal lines) and then put them together to construct a recognizable object.
OR recognition by components called geons
Describe how top-down processing is involved in speech.
We can hear sounds/words but we can only actually have speech segmentation (recognizing when one word ends and one begins) if we know the language - it turns out to be top-down processing.
Describe how top-down processing is involved in vision.
Ex: finding faces in forest - we can find easier when there’s meaning.
Describe how top-down processing is involved in pain perception.
Pain itself is bottom-up. However when pain is in different contexts it can change - ex: soldiers report little pain when injured severely because pain would mean medical discharge (top-down)
“What” pathway
Temporal lobe
Related to object recognition
Also the “perception pathway”
“Where” pathway
Parietal lobe
Related to location and spatial relations
Also the “action pathway”
What is the theory of unconscious inference?
Helmholtz - our perceptions are the result of unconscious assumptions, or inferences, that we make
about the environment.
What are the Gestalt principles of organization?
Good continuation
Pragnaz
Similarity
What are the Gestalt ideas about regularities in the environment?
What we know about the environment affects our perception.
ex: oblique effect - because most things are verticals or horizontals we perceive them better
Light from above assumption - in our environment most light comes from above - therefore certain textures/images will look different depending on where the shadowy part is.
Explain semantic regularities in a scene
Semantic regularities are the characteristics associated with the functions carried out in different types of scenes.
Use of schemas that give an environment meaning –> What the scene should contain
What is Helmholtz’s likelihood principle?
Perceptions are based on what is more likely - on what has already happened in the past.
What is the Bayesian inference?
Thomas Bayes - our estimation of the probability of an event occurring is based on prior probability (prior) and the extent to which the available evidence is consistent with the outcome (likelihood of the outcome).
