pscyh chp 4
Terms
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- sensation
- the process by which our sense organs recieve infor form the enviorment
- perception
- process by which the brain organizes and interprets sensory inputs
- psychophysics
- the study of how stimuli are translated into pscyhological experience
- 3 principles w/regard to sensation and perception
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1) there is no 1-1 conrrespondence between physical and psychological reality
2) sensation and perception are active processes
3) sensation and perception are adaptive - sensory receptors
- translate energy in the enviorment into neural impulses - detet physical energy - tuned to a particlar form of energy (ex: auditory recpetors)
- transduction
- the process by which physical energy is converted into electro-chemical energy
- 2 types of sensory thresholds
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1) absolute - minimum amount of physical energy needed for an observer to notice a stumulus (50% detection rate)
2)Just Notcieable Diff(JND) - lowest level of stimulatoin requred to sense change - Weber's Law
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JND in a stimulus is proportional to the magnitude of the original
ex: 2 candles, + 1 to acheive JND
ex: 100 candles, +50 to achieve JND - subliminal perception
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what happens when/if sensation and perception takes place w/out awareness (or below threshold)
ex: music,movies (lion king) - vision - electromagnetic radiation
- 1 form that we are used to - vision is adaptive and functional
- light detection is useful b/c - 3 ways
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1) light travels rapidly
2) light travels in straight lines
3)light interacts w/the surfaces of objs in the enviorment (reflec/absorb) - wavelength/amplitude/purity
- color/brightness/saturation
- cornea
- where light enters the eye - tough transparent tissue that covers and protects
- pupil
- adjustable openening which regulates/where light enters the eye
- iris
- muscle that controls opening of pupil - resonds to light intensity - unique
- lens
- bio-crystallin structure that focuses light rays onto the retina - change shape to focus
- accommodation
- process in which the lens changes its shape and bends light rays so that objs are in focus
- retina
- multilayered photo sensitive tissue lining the back surface of the eyeball; an extension of the brain
- optic disk
- where the optic nerve leaves the eye
- blind spot
- the pt. on retina where optic nerve cells leave the eye and where theare are no reciptor cells
- receptor cells - 2
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1) rods - black and white vision/found in periphery of retina/sensitive to moviement
2) cones - color and daylight/found in center/sensitive to fine detail - young-helmholt's trichromatic theory of color vision and problems with this theory - basic level
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color is explained by differential activation of 3 color elements in the eye - RGB
1)S-cones:blue
2)M-cones:green
3)L-cones:red
problems: aferimages left unexplained - included predictable color diff - hering's opponent process theory of color vision - higher level
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visual elements are grouped into 3 pairs 1)RG 2)BY 3)BW
explains complimentary color phenomenom - auditory system
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1)amplitude-loudness
2)wavelenght-pitch
3)complexity/purity-timbre - quality of a sound(ex. same note played on a piano & flute) - external ear - 2
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1)pinna - funnels sounds waves into the ear
2)auditory canal - a passageway where sound waves resonate & are amplified - middle ear - 2
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1)eardrum/tympanic membrane - oscillates in response to sound waves
2)ossicles - three tiny bones (anvil, hammer, stirrup)- sound waves get further amplified - inner ear - 3
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1) semicircular canals - balance
2)cochlea - 3 chambered tube shaped like a snail involved in the transduction of sound
3)basilar membrane - containes the hair cells stimulated by sound - skin senses - 3
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1) touch
2) temp
3) pain - pain is influenced by...
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culutral beliefs
ex:woman pregnancies - pain is...
- adaptive to a degree
- gate control theory
- emphasizes the role of the central nervous system in regulating pain - a pattern of nueral activity that inhibits incoming pain signals
- form perception
- the organiation of sensations into meaningful shapes and pattern
- gastalt laws of organization -2
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1) perceptions are not merely due to elementary sensation
2) the whole is > than the sum - gestalt principles of form perception - 6
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1) figure ground perception
2) similarity
3) proximity
4) good continuation
5) simplicity
6) closure - depth perception
- organization of perception in 3-D/ we make 3-D judgements based on 2-D retinal image via bonocular and monocular cues, auditry systeam and kinesthetic sensations
- interposition
- one obj blocks another
- elevation
- objs farther away are highter on plane of view
- linear persepctive
- parallel lines converge in distance
- texture gradient
- texture of dist objs appears to be finer rather than coarser
- shading
- brain interprets shading diff toward top/ bottom of obj
- aerial persepctive
- far objs are fuzzy
- familiar size
- familiar objs that appear small are inferred to be distant
- perceptual constancy
- the perception of objs as relatively stable despite changes in the stumualtion of sensory receptors
- color constancy
- tendency to perceive obj color as table under conditions of changing illumination
- shape constancy
- we maintain constant perception of shape of objs, depsite the fact that the same obj typically produces a new & diff impression on the retina everytime we encounter it
- size constancy
- objs do not differ in size when viewed from diff distances
- top down perceptual processing
- starts with observer's expectations/knowledge
- schemas
- top down perceptual processing/ mental represantations of what we expect or what we know about a situation
- bottom up perceptual processing
- processing that begins w/raw sensory data that feed up the brain / "feature detectors"