Sensation and perception Flashcards
Transduction
Senses must convert physical stimulus, energy into electrical changes in nerve receptor cell
“It’s no use if you can’t transduce”
Absolute threshold
Lowest stimulus level that an organism can detect 50% of the time
Difference threshold
Minimum difference in the intensity of two stimuli necessary to detect they are different
Cochlea
Fluid filled part of the inner ear that is connected with hearing (shaped like snail shell)
Rods vs. cones
Rods: operate under low light and are achromatic (nighttime receptors)
- allows us to see in dim light
- can’t see fine spatial detail or colors
Cones: operate under high illumination, chromatic, packed around fovea
- allows us to see in bright light, fine spatial detail, and different colors
Retina
Light sensitive, inner surface of the eye
Ganglion cells
Neurons found in retina that transmit visual information to the brain via the optic nerve
Optic nerve
Bundle of nerves cells that transmits sensory information for vision in the form of electrical impulses from the eye to the brain
Fovea
Provides sharpest vision
Trichromatic color vision theory
Color vision arises from three kinds of cones
- Blue: lower wavelength
- Green: medium wavelength
- Red: higher cones
Operant process theory of color vision
There are three opposing channels in our vision which is how humans perceive colors: blue vs. yellow, red vs. green, and black vs. white
Perceptual constancies
Our perception of an object’s features remains constant even when our viewpoint changes
Sensory adaptation
Reduction in sensitivity to a stimulus after constant exposure to it (living in a city so you’re used to noise)
Distal vs. proximal stimulus
stage in perception: distal –> proximal –> percept
distal: object that we see
proximal: energy that bounces off object and reaches our retina
percept: what we experience when we look at the tree
Lack of correspondence
When a percept does NOT correspond to the distal stimulus
E.g., perceptual illusions
Paradoxical correspondence
- When proximal stimulus does not correspond to distal stimulus, but the percept still does
- Our brains are correcting for missing or misleading information
Monocular vs. binocular depth cues
Information available to one eye vs. comparing the image received by both eyes
Convergence
The eyes rotate inward to focus on a nearby object (degree of rotation helps estimate object’s distance)
Retinal disparity
The apparent position of an object differs in both eyes
Depth perception innate?
Visual Cliff study- Gibson and Walk
- Visual illusion of cliff, baby placed at edge
- 6 month old avoids cliff, 2 month olds sense depth, but don’t have experience falling yet (aren’t afraid)
