Sensation and Perception Flashcards
(55 cards)
Sensation and Perception
> testing sensory-motor or conceptual decision making tasks
>use reaction time tests (less invasive)
Why study sensation & perception?
> everything you know entered through senses
consciousness is largely result of what see, hear, taste, touch, and smell
this is earliest part of psych (early believed in Tabula Rasa)
*Transduction
> converting environmental stimulus into nerve impulses
>sensory receptors convert environmental energy into nerve impulses (then to brain)
The Eye
> humans are primarily visual
retina- 3D cup at back, does transduction
fovea- dent in back
Photoreceptors
> convert light into nerve impulses
>ex. rods & cones (which are modified neurons)
Cones
>contributes to perception of color >refines image, acuity >in/around fovea (back,center) >less common than rods >need bright light
Rods
> sensitive to dim light (night vision)
can NOT perceive color
not a lot of acuity
outside of fovea and at edges
*Doctrine of Specific Nerve Energies
> quality of experience determined by sensory receptor stimulated and where info goes
Nerve Impulses
> AKA “action potential”
action potentials are all same
ex. rods/cones also respond to touch
Young-Helmholtz Trichromatic Theory
> suspected there are 3 diff types of cones (r,g,b)
>wave length- blue:short, green:middle, red:long
Opponent-Process Theory (Hering)
> three sub-processes choose one color to fire
>sub-processes made of opposing pairs (red-green, blue-yellow, back-white)
The Ishihara Test
> Red-Green color blindness (can still see yellow-disproves Trichromatic Theory)
most are only color deficient, can’t perceive certain combos
ex. Fish firing rate (thalamus changes firing rate to display color)
Negative Color Afterimages
> selectively fatigue black, yellow, green cones
>white slide allows r,w,b fully operational
Correct Eye Theory?
> both correct (how perceive/process color)
Eye: Trichromatic Theory
Brain: Opponent-Process Theory
Nystagmus
> eye almost vibrates, moves rapidly
muscles cause eye shifts
keeps image moving so rod/cones don’t fatigue
Stabilized Images
> pictures fixed on retina
no permanent damage
rods/cones fatigue and break circuit (parts of visual disappears)
cell assemblies/neural circuits formed w/experience
Cataract
> clouding of lens
can be surgically removed (take out lens)
surgery restores sight, but brain lacks neural circuitry (kids had trouble differentiating between circle/triangle)
changing angle would throw off brain
*Feature Detection
> cells in visual cortex respond to specific features
>plant electrobe in cortex to test activity in animals
*Feature Detectors
> edge detectors
complex cells
hyper complex cells
Edge Detectors
> simple cells, respond to lines w/certain orientations
Receptive Fields
> can be found in other places
>ex. groups of rods and cones in retina
Complex Cells
> more selective cells
>responds to particularly oriented lines, motion, color, and combos
Hyper Complex Cells
> perceives attributes, length, width, and simple shapes/contours
Inhibitory Connections
> prohibit signals from sending
