Sensation And Perception Flashcards
What does nativist theory of perception and cognition state?
Perception and cognition are largely innate.
What is the process in which physical sensation is changed into electrical messages that the brain can understand?
Sensory transduction
How does Structuralist theory state that the world is understood?
Perception is the sum total of sensory input. The world is understood through bottom-up processing.
What school of thought asserts that the world is understood using top-down processing? That is, people tend to see the world as comprised of organized wholes.
Gestalt psychology
What is the current stance on perception?
It is partially innate/sensory and partially learned/conceptual
What did James Gibson explain perceptual development as?
The increasing ability of a child to make finer discriminations among stimuli.
What is the dominant wavelength of light?
Hue (or color)
What is the cornea?
The clear, protective costing on the outside of the eye.
What muscles help the lens to focus an image of the outside world onto the retina?
Ciliary muscles
What are visual receptor cells and what are they collectively used for?
Rods and cones. They’re responsible for sensory transduction.
What are ganglion cells?
Cells that eventually carry the transduced message from the rods and cones to the brain. They make up the Optic nerve.
Describe cones.
Cones are particularly sensitive to color and daylight vision. They are used for visual acuity and are not good for nighttime vision. There are only cones in the fovea.
Describe rods.
Rods are sensitive to dim light and are used for night vision. They are very important for peripheral vision, but are not good with visual acuity. There are no rods in the fovea.
Why do cones see better than rods?
Because there are fewer cones per ganglion cell than rods per ganglion cell
Who proposed the opponent process theory for color vision?
Ewald Hering
What does the opponent process theory suggest?
It suggests we have 2 types of color sensitive cells: 1 to respond to blue-yellow colors and cones to respond to red-green. When one pair on a cone is stimulated, the other is inhibited.
Who was the tri-color theory proposed by?
Thomas Young and Hermann Von Helmholtz
What does the tri-color theory state?
There are 3 type of receptors in the retina: cones that respond to red, blue, or green.
Describe Helmholtz’s theory of color blindness.
Look this up!!!!!!!!
What is lateral inhibition?
Lateral inhibition allows the eye to see contrast and prevents repetitive info from being sent to the brain.
What is the minimum amount of stimulus energy that is needed to activate a sensory system?
The absolute threshold
What is Hermann von Helmholtz famous for?
The tri-color theory and a theory of color blindness.
Who discovered that cells in the visual cortex are so complex that they only respond to certain types of cells?
Ex./ Vertical lines, right angles, etc.
David Hubel and Torsten Wiesel
What is binocular disparity?
Has been called the most important depth cue. Our eyes view objects from 2 slightly different angles, which allows us to create a 3D picture.
_____ gives us clues about how far away an object is if we know how big the object should be.
Apparent size
What is interposition?
The overlap of objects shows which objects are closer.
What is texture gradient?
How we see texture or fine detail differently from different distances
What is the motion parallax?
Movement is perceived through the displacement of objects over time, and how this motion takes place at seemingly different paces for nearby or faraway objects.
Ex./ Ships far away appear to be moving slower than closer ships moving at the same speed.
Who developed the visual cliff?
Eleanor Gibson and Richard Walk
What is the visual cliff?
An apparatus used to study whether depth perception is innate. Looked like a table with a “cliff” at the end, but a thick layer of glass continued. Babies and animals were studied and they both avoided this visual “cliff.”
What is a difference threshold?
How different two stimuli (in magnitude) must be before they are perceived to be different.
What is an important thing to remember when determining difference thresholds?
The difference is not between the standard and average comparison stimuli, but their ratios.
Ex./ Assume the JND for noticing candles is 1:10. That is, in a room of 10 candles, it would take 1 more candle to recognize a difference. In a field of 10,000 candles, however, it would take about 1,000 candles to recognize a difference.
Describe Weber’s Law.
What’s important in producing a JND is not the absolute difference between the two stimuli, but the ratio.
What does JND stand for and what is it?
JND- Just Noticable Difference.
One JND needs to be added to or subtracted from a stimulus for a person to say that she notices the difference.
What does signal detection theory suggest?
Other nonsensory factors influence what the subject says she senses. These nonsensory factors include experiences, motives, and expectations.
What is the term used for measuring how risky the subject is in sensory decision-making; based upon nonsensory factors?
Response Bias
Another way to define: the tendency of subjects to respond in a particular way due to nonsensory factors.
