chapter 6 Flashcards
what is sensation
The awareness of properties of an object or event when a sensory receptor is stimulated
what is perception
The act of organizing and interpreting sensory input as signaling a particular object or event
what is psychophysics
Studies of the relationship between physical stimuli and the sensation & perception that those stimuli effect.
what is an absolute threshold
the minimum stimulus energy needed to detect a particular stimulus 50 percent of the time
what is the difference threshold (JND)
the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference
what is weber’s law
computes the JND; how much does it have to change before we know its changing
Ernst weber
what is the stimulus for vision
light stimulus= the photon
what are the properties of light
wavelength, amplitude, frequency
what are the structures of the eye
pupil
iris
cornea
retina
fovea
optic nerve
lense
what does the pupil do
lets light in
what does the iris do
determines how much light is let in
what does the cornea do
protects eye, refracts light
what does the retina do
photoreceptors (rods + cones)
*Rods (100-120 million)
* Very sensitive to light
* Only register shades of gray
*Cones (5-6 million)
* Sensitive to particular
wavelengths
* Allow color vision
what is the fovea
where light needs to hit to see
what is the optic nerve
where information leaves the eye
what does the lense do
flattens or fattens aka bends light in order to make it to fovea
what is the Young-Helmholtz Trichromatic theory
that we have cones in our eyes that see blue, red, and green
what is Herings Opponent process theory
humans perceive color in terms of three opposing color pairs: red versus green, blue versus yellow, and black versus white
theory suggests that one color in a pair suppresses the other, so we see yellowish-greens and reddish-yellows, but not reddish-greens or yellowish-blues.
explains afterimages
what is transduction
cells translate world language to brain language
what is accomdation
when the lense changes shape
what is myopia
nearsighted, eyeball too long
what is hypermetropia
farsighted; light rays come to focus behind retina
what is an astigmatism
shape of cornea is abnormal