Sensation and Perception Flashcards
Weber
just noticeable difference
Fechner
Weber’s Law
Wertheimer
Gestalt psychology; phi phenonemon
absolute threshold
minimum of stimulus energy needed to activate the sensory system (i.e. before it can be perceived)
limen
another word for threshold
difference threshold
amount of stimulus energy added or subtracted from a stimulus for a difference to be noticed
just noticeable difference
measures same thing as difference threshold but units are different. if 2 oz is the point where difference in weight is noticeable, then 2 oz = 1 JND
Weber’s Law
JND is produced by ratio of difference between two stimuli not the absolute difference
Weber’s fraction
constant K; the smaller the K the better the sensitivity
Fechner’s Law
relates the intensity of the stimulus to the intensity of the sensation
Stevens’ power law
same as Fechner’s Law (intensity of stimulus to intensity of sensation) but different formula
response bias
how risky a person is in sensory decision-making (based upon nonsensory factors)
ROC curves
used to graphically summarize a subject’s responses in a signal detection experiment
John Swets
refined use of ROC curves
stages of sensory processing
reception, transduction, sent to projection areas
duplicity theory of vision
there are two kinds of photoreceptors in the retina
Are there more rods or cones in the human eye?
rods
What happens at the optic chiasm?
Nasal fibers from left eye go to right side of brain, nasal fibers from right eye go to the left side of brain; temporal fibers from left go to left and temporal fibers from right go to right (end result: information from left visual field of both eyes goes to the right side of the brain and vice versa)
brain structures involved in visual processing
lateral geniculate nucleus of thalamus, visual cortex, and superior colliculus
order that light passes through eye
cornea, pupil, lens, rods and cones, bipolar cells, amacrine cells, ganglion cells, optic nerve
blind spot
corresponds with optic disk (no photoreceptors here)
Hubel and Wiesel
feature detection theory (Nobel Prize 1981), single cell recording
feature detection theory
certain cells in the cortex are maximally sensitive to certain features of stimuli (simple, complex, and hyper complex cells)
simple cells
responds to orientation and boundaries of object
complex cells
responds to movement
hypercomplex cells
responds to shape/abstract concepts
pigment in rods
rhodopsin (made up of vitamin A deriviative retinal and opsin)
physiology behind dark adaptation
also known as bleaching; rhodopsin splits into retinal and opsin when light is absorbed. Adaptation occurs after rhodopsin has regenerated.
lateral inhibition
when adjacent retinal cells inhibit one another; this sharpens and highlights borders between light and dark areas
what is colour perception related to?
the wavelength of the light entering the eye