Chapter 3 Eye Flashcards
Perception
Making sense of info
Cognitive process, involves selection & interpretation of external stimuli & transfer of external stimuli (light, sound waves, chemicals)
Into neural energy =cabled transduction
Transducer
External stimuli transferred/changed into chemical/neural impulses
Psychophysics
Study of physical stimuli are translated into psychological experiences
Also involves how 5 senses affect our behaviors
Absolute thresholds
Minimum amount of stimulation that an organism can detect 50% of the time
Goes beyond boundary referred to as neural or absolute threshold
Triggers neural impulses
Difference thresholds
JND
Smallest difference in amount of stimulation that a specific sense can detect
Notice change decrease/increase in 5 senses
Sensory adaption
Involves gradual decline in sensitivity to prolonged stimulation (you get used to this one)
Subliminal perception
Stimuli presented below ones absolute threshold
Visual/auditorial message presented below our sensory threshold
May influence actions but only subtly
James viary
Cornea
Protector, round transparent, shell of the eye
Bends light rays as they enter eye
Lens
Transparent eye structure
Focuser, focuses light rays falling on retina (visual image)
Pupil
Opening in center of iris, regulator of light passing through rear of eye
Dilates/contracts depending on amount of light present in environment
Iris
Ring of muscle gives colors
Muscle regulates size of pupil
Ciliary muscles
Small muscles attached to lens - controls shape & focusing accommodation
Accommodation
Reflexive change in lens of eye to bring into sharp focus objects at different distances
Becomes difficult as we age, lenses more rigid & ciliary muscles become weak
Aqueous Humor
Nourishes cornea & structures at front of eye
Vitreous humor
Keeps eyeball rounded by filling Space behind lens
Fluid fills interior parts of eye keeping space filled & rouunded
Retina
Neural tissue lining inside back surface of eye
Vision begins taking place here where light energy is traduced/transferred into neural energy on back
Photoreceptors
Cells are light sensitive
2 types of rods & cones; names based on shape of receptors, rods =blunt flat, cones = pointy
Rods
Specialized visual receptors that play key role in night/peripheral vision
Nocturnal animals = lots of rods
Too many rods = lower ability to see color during day
Cones
Specialized visual receptors play key role in daylight/color vision
Best in well lit, responsible for color vision
More cones = better color vision
Optic nerve
Axons from retina that connect eye w/ brain
String of sensory neurons take messages to occipital lobe
Fovea
Tiny spot in center of retina contains only cones
Cones are detail oriented
Blind spot
Area where optic nerve exists eye to brain
No rods/cones where optic nerve exists the eyes to brain
Optic chiasm
Optic nerves converge so signals from each half of visual field carried opposite sides of visual cortex
Trichromatic: young helmholtz
Red green and blue
Human eye has 3 types of receptors w/ differing sensitivities to other wavelengths
First by Thomas young revised by Hermann Von helmholtz
Opponent process
Color perceived in 3 channels paired of antagonist colors
Blue & yellow processors; red & green processors; black & white
Each processor capable of responding to either of two colors not both simultaneously
Afterimage
Visual image persists after stimulus removed rods and cones activated after image gone
Color blindness
8% males .5% females
Sensation
Conversion of energy from environment into pattern of responses by nervous system
