3 Basic Points
Sensation is the building block for (almost) all what?
Cognition
What are rods, what do they do, and where are they located?
Specialized neurons which are high sensitivity to light
‘Colorblind’ - do not help with color vision
Used for ‘Night vision’ because they can detect low levels of light
Not as good at discriminating fine details
Not located at the center of the eye (the fovea)
What are the four Gestalt Principles?
Proximity, similarity, good continuation, and simplicity/good figure (pragnanz)
We use top-down processing: our knowledge, expectations, context, experience, etc. to resolve ambiguity. Perception is constructed through this active process.
Describe the "what" versus "where pathways of the brain?
What: discriminating between objects
Where: discerning the location of an object
Identical sensations can lead to _______ .
Very different perceptions
What are cones, what do they do, and where are they located?
Specialized neurons which detect finer details
Color vision
Mostly at the center of the eye (the fovea)
Three distinct types (underlies color vision)
What is apparent movement as it relates to bottom-up processing?
Optical illusions that create the perception of movement where there is none.
What are the ways we resolve ambiguity of stimuli?
Context: what else is there around
Physical regularity: light-from-above assumption (light typically comes from above us)
Semantic regularity: scene schema (knowledge of what a given scene typically contains
Oblique effect: easier to perceive vertical and horizontal lines than other orientations
Where is the "what" pathway connected?
Ventral pathway to the temporal lobe
Our psychological perception is nothing like the _________ that our nervous system senses.
How do we perceive color?
Using 3 types of cones, each most sensitive to a particular wavelength. The color we perceive is determined by the difference in the signals received.
What are emergent figures as it relates to bottom-up processing?
An entity produced by the interaction of a small or simple elements in the visual system.
What is experience-dependent plasticity?
We learn regularities through experience, and they change how our neurons respond.
Ex.: Kittens exposed only to vertical (or horizontal) stripes respond only to vertical (or horizontal) stripes
Where is the "where" pathway connected?
Dorsal pathway to the parietal lobe
Describe the Perceptual process.
Physical Stimulus Energy -> Sensory Receptors -> Neurons -> Brain
What is the inverse projection problem?
The world is 3-D, and our retinas are 2-D, but we perceive the world in 3-D.
What did the structuralism theory of bottom-up processing argue?
Perception is a sum of our senses
How does top-down processing influence pain perception?
Bonus: what was did the expectations pain effect study find
Pain perception can depend on attention and emotional expectations.
Beecher (1959) found that WW2 soldiers at Anzio beachhead reported less pain because their injuries were viewed positively - they got to go home
Describe what a double dissociation entails?
Two distinct cognitive functions (e.g., recognizing objects vs. recognizing faces) are shown to be independent and rely on different brain systems.
Ex.: "what" is damaged but "where" is still functional and vice versa
What are sensory receptors and what do they respond to?
Cells (neurons) specialized to respond to environmental energy. Each sensory system’s receptors respond to a specific type of energy.
What is a blind spot and how do we overcome it?
The spot where the optic nerve leaves the retina which has no photoreceptors and therefore cannot detect (see) light.
Our brains “fill in” this space using the best guess as to what is there.
What did the Gestalt Movement argue about perception?
Argued that the laws of perception are intrinsic and that the whole of our perception is not a sum of the parts.
How does top-down processing impact color and size perception?
Bonus: name a few illusions this applies to.
Color constancy: our ability to perceive colors as relatively constant over varying illuminations.
Ex.: blue and black dress illusion
Size Constancy: our ability to see the size of objects as relatively constant despite the fact that the size of objects on the retina vary greatly with distance.
Ex.: Ames room and the ponzo illusion
Why are double dissociations important?
Double dissociations are necessary to show that two mental processes function independently of each other.