Psych test #2

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sense: a system that translates info from outside the nervous system into neural activity
must detect, encode, and transfer info
sensation: message received from the senses
accessory structures: first step in sensation
modifies energy
ex. outer part of ear, lens of eye
transduction: -converts incoming energy into neural activity
-takes place at sensory receptors
-detect certain forms of energy and respond by firing action potential
-ex. change light waves to color
coding: allows neural impulses to be changed into certain properties
doctrine of specific nerve endings: stimulation of a particular sensory nerve provides codes for that sense no matter how stimulation takes place (ex. pressure on eye)
temporal code: changes in the timing of firing
spatial code: location of firing neurons relative to others
absolute threshold: the minimum amount of stimulus energy that can be detected 50% of the time
subliminal stimuli: stimuli too weak or brief to be perceived
supraliminal stimuli: stimuli that fall about the absolute threshold and are consistently perceived
signal-detection theory: predicts how and when a signal will be detected amid background noise
sensitivity: -the ability to detect a stimulus from background noise
-influenced by intensity of signal, capacity of sensory system, amount of background noise
response criterion: -internal rule used to decide whether or not to report a stimulus
-affected by motivation, wants, needs, and expectancies (ex. airport security)
just-noticeable difference: -the smallest detectable difference in stimulus energy that can be detected 50% of the time
-the weaker the stimuli, easier to detect small differences
Weber's Law: -the more intense the stimulus, the greater the increase in stimulus intensity required for the increase to be perceived
-two stimuli must differ by a constant minimum percentage, rather than a constant amount
Light-electromagnetic radiation: -visable light
-electromagnetic radiation of a wavelenght between 400 and 750 nanometers
-does not need a medium to pass through
sensation of light: -light intensity (how much energy the light contains, determines brightness of light)
-light wavelenght (provides color, defferent wavelenghts produce different colors)
Eye: -cornea (light enters the curved, transparent, protective layer)
-pupil (light passes through an opening in the eye)
-iris (adjusts the amount of light allowed into the eye)
-lens (lies behind the pupil and bends light rays, focusing them on the retina)
- retina (surface at the back of the eye where light rays are focused)
photoreceptors: -specialized cells in the retina that convert light energy into neural activity
-contain photopigments (chemicals that respond to light)
-two types, rods and cones
rods: -has only one pigment
-distributed throughtout the retina, except at the fovea
-faciliatate peripheral vision
-mediate nighttime vision
-receive all colors as shades of gray
cones: -concentrated in center of the retina at the fovea
-mediate daytime vision
-mediate color vision
-provide a sharper image than rods
interactions in the retina: -rods and cones synapse with bipolar cells
-following this, it synapses with ganglion cells
-axons of the ganglion cells gather together to form the optic nerve (carries visual impulses from the retina to the brain)
trichromatic theory: -3 types of color receptors that are each receptive to a different primary color (red, blue, green)
-the ration of the activites of the 3 types of cones indicate what color will be sensed
-color vision is coded by the pattern of activity of the different cones
opponent-process theory: -3 distinct receptors (red green, yellow blue, white black)
-each element signals one color or the other, but never both
-gray results when lights of the 2 colors are mixed together
-supported byt he phenomenon of negative afterimages
trichromats: -people with normal color vision
-have 3 distinct visual pigments
dichromats: -lack one of the 3 pigments
-most are red green blind
monochromats: -have no color vision
-receive visual info through rods only
sex linked recessive trait: -associated with a gene on the X chromosome
-males are more prone to color blindness than females
sound: -repetitive fluctuation in the pressure of a medium like air
-vibrations produce the fluctuations in pressure that constitute sound
-Speech (vocal cords produce vibration into the air, creates waves)
Optic nerve: blind spot
optic chiasm: -half the fibers cross over to the opposite side of the brain
-info from the inner (nasal) half of the retina cross to the opposite side of the brain
-info from the outer (temporal) half of the retina remain on same side
-info from both eyes reaches both sides of the brain
-visual info transmitted to thalamus and then to primary visual receiving area in occipital lobe
loudness: -determined by amplitude of the sound wave
-waves with greater amplitude produce louder sounds
-measured in decibels (dB)
pitch: -depends on frequency of sound waves
-high frequency = high pitch
-humans can hear between 20-20,000 Hz
timbre: -quality of sound
-determined by complex wave patterns
wavelength: distance from one peak to the next
frequency: -number of complete waveforms that pass by a given point in space every second
-measured in hertz (Hz)
amplitude: -intensity
-difference between peak and baseline of a waveform
pinna: -the crumpled part
-funnels down through the ear canal
-sound waves collect in outer ear
tympanic membrane: -eardrum
-sound waves cause eardrum to vibrate
ossicles: -hammer, anvil, stirrup
-amplify changes in pressure
oval window: -membrane that seperates middle and inner ear
-vibration is up to 90 times greater at this point
cochlea: -amplified vibration transmitted to fluid in the cochlea
-movement of fluid in the cochlea bend the auditory receptor cells (hair cells)
-results in neural impulses in the adjacent auditory nerve
-nerve transmits signals through the medulla and thalamus to the auditory cortex of the temporal lobe
Place theory: -describes a spatial code for frequency
-proposed that pitch is determined by the part of the basilar membrane stimulated
-explains the ability to perceive high frequency tones, but does not explain the ability to perceive lower ones
frequency matching theory: -for low frequency sounds, the frequency of nerve impulses matches the frequency of the stimulus
-temporal code
volley theory: -differnt sets of fibers within the auditory nerve fire in successive rounds, with the pattern determining the pitch
-explains the perception of frequencies between 1000-4000Hz
touch: -energy detected from deformation of tissue, ususally the skin
-receptors in or below the skin transduce this info into neural activity
-changes in touch constitute the most important sensory info
coding of touch: -intensity (heaviness) coded by the firing rate and number of neurons stimulated
-location: coded by the spatial organization of the info
-topographical map of brain: differentially sensitive
skin senses: -pressure (only one with identifiable receptors)
-warmth
-cold
-pain
-not clear how receptors work together (wetness develops from touching adjacent cold and pressure spots, cold and warm spots produce a feeling of hot)
pain: -receptors are free nerve endings
-A-delta fibers carry sharp pain (myelinated to carry messages quickly)
-C fibers carry chronic, dull aches and burning sensations
gate control theory: -nervous system can process only a limited amount of sensory info at any one time
-when too much info is being received, cell sin the spinal cord act as a gate, blocking some pain signals
-ex. massaging area, distracting activity, hot or cold, can reduce pain
referred pain: -pain sensation in one part of the body is perceived as coming from another part
phantom pain: -pain sensation felt in missing limb
taste: -taste buds are the receptors, grouped together in stuctures called papillae
-10,000 taste buds in mouth
-discriminates between sweet, salty, sour, bitter, umami (enhances other tastes), and astringent (produced by tannins, tea)
-each taste bud responds best to 1-2 of these categories
sweet and bitter: signaled when chemicals fit into specific receptor sites
sour and salty: more direct effects on the ion channels in membranes of taste buds
flavor: -smell and taste converge to produce flavor
-food tastes good due to olfactory system more so than the taste system
-olfactory and taste pathways converge in the orbitofrontal cortex, where they also respond to sight and texture of food
olfaction: -sense odor in upper part of nose
-odor molecules readch olfactory receptors by either passing directly through the nostrils or rising through an opening in the palate
-molecules bind to dendrites in the nose, which leads to action potentials
proprioception: allow us to know the position of body and what each part is doing
vestibular sense: -provides info about the position of the head in space and its movements
-sense of balance
-vertigo
vestibular sacs: -organs in the inner ear that connect the semicircular canals and the cochlea
-contribute to the body's sense of balance
semicircular canals: tubes in the inner ear whose fluid, when shifted by head movements, stimulates nerve cells
vestibular system has neural connections:: -cerebellum (helps coordinate body movement
-digestive part of ANS (responsible for nausea)
-muscles of the eye (create vestibular-ocular reflexes (when head moves in one direction eyes more in opposite direction, allows us to fixate on one point))
perception: the process through which sensations are interpreted, using knowledge experience, and understanding of the world, to create meaningful experiences
bottom up processing: -aspects of recognition that depend of the info about the stimulus that comes up to the brain from the sensory receptors
-certain cells respond to certain stimuli
-the brain then recombines this data to create the perceptual experience
-certain features are more important than others (rely on large scale features, such as hair and head shape)
top down processing: -use knowledge in making inferences to recognize objects, especially when sensory info is vague
-experiences creat schemas, which then can bias our perception
-can create a perceptual set, a predisposition to perceive a stimulus in a certain way
-makes educated guesses (can lead to wrong conclusions)
network processing: -utilize both top down and bottom up processing
-parallel distributed processing models (various elements of the object are believed to be simultaneously analyzed by a number of widely distributed, but connected, neural units in the brain. Units work in parallel)
attention: -the process of directing and focusing certain psychological resources to enhance perception, performance, and mental experience
-used to direct our sensory and perceptual systems, select specific info for further processing, ignore unwanted stimuli
directing attention: -Voluntary control (purposely focus attention in order to perform a task, reflects top down processing, overt orienting)
-Involuntary attention (bottom up process, abrupt changes in lighting or movement, covert orienting)
ignoring information: inattentional blindness: dont pay attention to certain stimuli in the environment
divided attention: -easy if one task is automatic
-more difficult if both require attention (but if tap different kinds of attentional resources, it is possible)
-if 2 tasks require same kind of attention, performance on both tasks will be poor
parallel processing: -the ability to search for targets rapidly and automatically
-filter out irrelevant info
-stroop test
stroop test: -a measure to assess the ingibition of automatic responses
-it is automatic for us to read words, compared to naming colors, need to inhibit automatic response
gestalt laws: -proximity
-similarity
-continuity
-closure (fill in missing contours of shape)
-common fate
-texture
-simplicity
synchrony: stimuli that occur at the same time are likely to be perceived as belonging together

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