psych ch 4

Cards

sensation stimulation of sense organs
perception selection, organization, and interpretation of sensory input
psychophysics study of how physical stimuli are translated into psychological experience
three basic principles in regard to sensation and perception 1. there is not a one-one correspondance between physical and psychological reality 2. sensation and perception are active processes 3. sensation and perception are adaptive
sensory receptors translate physical stimulation into neural signals (called transduction)
absolute threshold sensory systems require a minimum amount of energy for activation
sensory systems are... sensitive to changes in stimulation level; sensory receptors are tuned to a particular form of energy
Fechner concept of the threshold: absolute threshold is detected about 50% of the time
Just Noticible Difference (JND) smallest difference detectable (minimum difference in stimulation that is just noticeable)
Webster's Law size of the JND is proportional to the size of initial stimulus
subliminal perception existence vs. practical effects
sensory adaptation decline in sensitivity
signal-detection theory sensory processes and decision processes
the eye can detect electromagnetic radiation
vision is... functional: detection of movement, detection of color, etc.
light detection is useful because travels rapidly (no delay like hearing), travels in straight lines (no distortion), interacts with the surfaces of objects in the environment (reflected or absorbed)
cornea where light enters the eye
lens focuses the light rays on the retina
iris colored ring of muscle, constricts or dilates via amount of light
pupil regulates teh amount of light
retina absorbs light, processes images, and sends info to the brain; light travels through retina to impinge on photoreceptors at the back of the eye
optic disk where the optic nerve leaves the eye/ blind spot
receptor cells: rods black and white/ low light vision; found in periphery of retina and are sensitive to movement but not fine detail
receptor cells: cones color and daylight vision; found in center of retina (fovea) and are sensitive to fine detail and color
adaptation becoming more or less sensitive to light as needed
receptive fields areas that when stimulated, affect the firing of a cell
center-surround light falling on the center has the opposite effect of light falling on surrounding areas
lateral antagonism activity in one cell opposes activity in surrounding cells
main visual pathway in the brain thalamus, LGN, primary visual cortex, occipital lobe
secondary visual pathway in the brain superior colliculus, thalamus, occipital lobe
primary visual cortex pathways: Dorsal Stream "where pathway", motion and depth
primary visual cortex pathways: Ventral Stream "what pathway", form and color
Hubel and Wiesel 1960's, microelectrode recording of axons in primary visual cortex of animals; discovered feature detectors: neurons that respond selectively to lines, edges, etc.; Nobel prize in 1981
feature detectors response of an orietnation detector in primary visual cortex to a bar of light at various orientations; other cells prefer different orientations and/or different locations in the visual field
demensions of color: hue apparent color of an object; determined by wavelength (longer = red and shorter = violet)
demensions of color: brightness intensity of a color
demensions of color: saturation purity of the color
three types of cones in the eye S: blue, M: green, L: red
Young-Helmholtz: Trichromatic Theory color is explained by diffential activation of 3 color elements in the eye; receptors for red, green, blue-- color mixing; couldn't account for negative color afterimages
Hering: Opponent-Process Theory colors are derived from activity of 3 antagonistic systems: black-white, red-green, and blue-yellow
subtractive color mixing less light; applies to paints, color filters-- mix of all colors results in black
additive color mixing more light; applies to lights only-- mixing of all colors results in white
feature detection theory bottom-up processing
subjective contours contours are perceived when none actually exist (invisible triangle pic)
form perception top-down processing
Gestalt psychologists whole is more than the sum of its parts
reversible figures drawing that is compatible with 2 interpretations
perceptual sets readiness to perceive a stimulus in a particular way
inattentional blindness failure to see fully visible objects or events in a visual display
bottom up processing detect specific features of stimulus, combine specific features into more complex forms, recognize stimulus
top-down processing formulate perceptual hypothesis about the nature of the stimuls as a whole, select and examine features to check hypothesis, recognize the stimulus
distal stimuli outside the body
proximal stimulus energies impinging on sensory receptors
binocular cues clues from both eyes together; retinal disparity and convergence
monocular cues clues from a single eye; motion parallax, accomodatin, and pictoial depth cues
perceptual constancies stable perceptions amid changing stimuli: things like size, shape, brightness, hue, and location in space
optical illusions discrepancy between visual appearance and physical reality
sounds waves: amplitude loudness
sounds waves: wavelength pitch
sound waves: purity timbre
external ear pinna; vibration air
middle ear ossicles; bibration bones (anvil, hammer, and stirrup-- 3 tinniest bones); lever system designed for amplification
inner ear cochlea, etc.; waves in a fluid; basilar membrane (inside the cochlea) contains hair cells (auditory receptors) that are stimulated by sound
auditory pathway sound waves vibrate bones in mid ear; stirrup hits against the oval window of the cochlea; sets fluid inside in motion; hair cells are stimulated with the movement of the basilar membrane; physical stimlation converted into neural impulses; sent through the thalamus to the adutory cortex (temporal lobes)
determining pitch: Place Thory (helmholtz) different pitches cause different areas of the basialr membrane to vibrate
determining pitch: Frequency Theory (Rutherford) different pitches cause the entire membrane to vibrate at different rates (volleys)
gustatory system: pathway taste buds, neural impulse, thalamus, cortex
flavor is comprised of both taste AND smell
olfactory system stimuli volatile chemical substances
olfactory smell; only system that doesn't send info through the thalamus (instead directly to the cortex); olfactory cilia in nasal passages
olfactory pathway neural impulse, olfactory nerve, olfactory bulb (brain)
three classes of skin receptors touch: physical contact of objects with skin; temperature, and pain
touch senses pathway sensory receptors, spinal column, brainstem, cross to opposite side of brain, thalamus, somatosensory (parietal lobe)
pain receptors free nerve endings (just like temp); two pathways: fast and slow
gate-control theory incoming pain sensations must pass through a gate in the spinal cord that can be closed thus blocking ascending pain signals
vestibular system monitors the position of your body in space; receptors are fluid and hari cells in the semicircular canals; head movement causes fluid to move which stimulates hair cells notifying the brain exactly which way the head has moved