Chapter 2-sensation & perception Flashcards
sensation
transduction, conversion of physical, electromagnetic, auditory, and other info from environment into electrical signals to the CNS
perception
processing of sensory info
difference threshold
minimum difference in magnitude between 2 stimuli that is required to detect the difference
Weber’s law
there is a constant ratio between the change in stimulus magnitude needed to produce a difference threshold and the magnitude of the original stimulus; for larger magnitude stimulus, the actual difference must be larger to perceive that difference
signal detection theory
internal (psychological) and external (environmental) context influences the perception of the same stimuli
Response Bias
tendency to systematically respond to a stimulus a particular way due to nonsensory factors.
signal detection experiment
consists of many trials where stimulus may or may not be presented; catch trials: signal presented; noise trials: signal not presented (think of white noise); after each trial participant asked if signal was presented; 4 outcomes: hits (correctly perceived the signal), miss (fails to perceive signal), false alarms, and correct negatives (correctly identifies that no signal was given
adaption
decrease in stimulus perception over time
retina
back of the eye, converts incoming photons of light into electrical signals
duplexity/duplicity theory of vision
retina contains 2 kinds of photoreceptors, rods and cones
cones
color perception, fine details; come in three different forms for long, medium, short wavelenghs
rods
more functional in reduced illumination, contain rhodopsin, better for night vision and peripheral
fovea
central retina where best visual acuity, contains only cones
visual pathway
photoreceptors-bipolar cells-ganglion cells-optic nerve-hemidecussation-LGN of thalamus-visual cortex
amacrine and horizontal cells
receive input from multiple retinal cells before passing on info to ganglion cells
parallel processing
ability to simultaneously analyze and combine info on color, shape, and motion. Feature detection: have cells that specialize in color, shape, motion
parvocellular cells
ability to see shape and distinguish object from background, color, fine detail, low temperal resolution (only can see stationary or slowly moving objects)