ch. 3 - sensation and perception Flashcards
sensation
the detection or basic sensory experience of environmental stimuli
perception
meaningful organization or interpretation of sensory information
sensation
the result of stimulation of the sensory receptors by forms of energy
transduction
the process of sensory receptors convert physical energy into electrical impulses transmitted via neurons
stimulus threshold
the strength of a stimulus needs to be detected and activate sensory receptor cells
absolute threshold
the smallest possible strength of a stimulus that can be detected half the time
difference threshold
the smallest possible difference between 2 stimuli that can be detected half the time
just noticeable difference
another name for the difference threshold
Webers Law
a theory which states that the ability to detect a change in stimulus strength depends on the intensity of the original stimulus
sensory adaptation
the gradual decline in sensitivity to a constant stimulus
subliminal perception
the detection of stimuli below conscious perception or the awareness threshold
mere exposure effect
repeated exposure to a stimulus increases liking towards that stimulus
electromagnetic energy
the energy of vision perception, light waves which vary in wavelength
cornea
clear membrane which covers the front of the eye, helps to direct and gather incoming light
pupil
the black opening in the eyes center
iris
the ring of muscular tissue which contracts and expands to control the amount of light entering the eye
lens
thins or thickens in a process called accommodation to bend and focus incoming light to fall on the retina
myopia
light focuses in front of the retina (aka nearsightedness)
hyperopia
light focuses behind the retina (aka farsightedness)
presbyopia
development of a brittle and inflexible lense, a type of hyperopia
astigmatism
a curved eyeball leads to blurry vision
retina
the thin, light-sensitive membrane at the back of the eye, contains rods and cones
rod
the long, thin, and blunt photoreceptor in the peripheral areas of the retina, very light-sensitive and helps with night vision, reaches maximum light sensitivity in 30 minutes
cone
short, fat, and tapered photoreceptor near the center of the retina, sensitive to color and details which requires more light to function, reaches maximum light sensitivity in 5 minutes
fovea
the center of the retina, concentrated with cones
optic disk
an area of the retina with no rods or cones creates a blind spot in our vision
bipolar cells
specialized neurons which collect sensory information from rods and cones in its specified receptive field then funnels it to ganglion cells
ganglion cells
specialized neurons in the retina which does the preliminary processing of visual information before its sent to the brain, receives information from a few cones but hundreds of rods
visual acuity
the ability to see fine details, depends on cones (because there is too much rod information which has to be condensed when sent to the brain)
optic nerve
formed of the axons of ganglion cells, exits the back of the eye through the optic disk towards the brain
optic chiasm
point in the brain where the optic nerve of an eye splits into 2 fibers which continue on to the same or opposite side of the brain to the thalamus
hue
aka color, a characteristic of color that is the wavelength of its light
saturation
aka purity, a characteristic of color that is how many wavelengths it takes to produce that color
brightness
aka intensity, a characteristic of color that is the amplitude of its light wave, a high amplitude is perceived as a higher intensity
white light
the perception of all colors wavelengths reflected off an object
trichromatic theory of color
theory of color vision: cones are either red, blue, or green-sensitive and respond to their corresponding wavelengths
red-green color blindness
a condition caused by non-blue-sensitive cones to respond to both red and green wavelengths
afterimage
a visual experience that occurs after an original source of stimulation stops
opponent-process theory
theory of color vision, the 4 basic colors are divided into opposing pairs of color-sensitive neurons, the stimulation of one inhibits the other
audition
aka hearing, capability to respond to a wide range of sounds
sound waves
rhythmic vibration of air molecules, physical stimulus of audition
amplitude
aka loudness, measured in decibels
frequency
aka pitch, relative highness/lowness of a sound, measured in hertz
timbre
the distinctive quality of a sound from its combination of frequencies
pinna
apart of the outer ear, the skin or cartilage that catches and funnels soundwaves into the ear canal (aka auditory canal)
eardrum
apart of the outer ear, a tightly stretched membrane that vibrates at the same frequency of the soundwave
hammer, anvil, and stirrup
the bones of the middle ear that successively double sound amplification and sends the vibration to the oval window (to the inner ear)
conduction deafness
a condition caused by the damage or brittle of the hammer, anvil, and stirrup, can be treated with a hearing aid
cochlea
spiral, fluid-filled tube in the inner ear which ripples in response to vibrations in the oval window
basilar membrane
apart of the inner ear, membrane within the cochlea that responds to fluid ripples
hair cells
apart of the inner ear, sound sensory receptors embedded within the basilar membrane converts soundwaves into neural impulses, stimulating the auditory nerve
nerve deafness
a condition caused by damage to hair cells, cant be treated with a hearing aid (needs a cochlear implant)
frequency theory
explains how low-frequency sounds are transmitted to the brain through the vibration of the basilar membrane at the same frequency as the sound wave
volley principle
hair cells fire in sequences )volleys) so that the brain can get faster rates of information
place theory
different frequencies cause different vibrations at different locations in the basilar membrane and excite different hair cells
olfaction and gustation
the chemical senses
olfactory receptor cells
specialized receptor cells in the nasal cavity, respond to molecules emitted by a smelly substance into the air, constantly replaced and only live 30-60 days
olfactory nerve
passes along neural messages from stimulation from airborne molecules that activate specific combinations of receptors
olfactory bulb
at the end of olfactory nerves, its axons form the olfactory tract which extends to all parts of the brain (eg temporal lobe and limbic system)
gustation
aka taste, occurs when saliva dissolves chemical substances and activates receptor cells in taste buds
sweet, salty, sour, bitter, umami
the 5 basic tastes
skin senses
the sense of the body’s physical status or its interactions with objects in the environment
body senses
the sense of the body’s position and orientation in space
skin
the largest and heaviest sense organ
pacinian corpuscle
touch receptor, converts pressure stimulation into neural messages that are sent to the brain
pain
unpleasant sensory or emotional experiences associated with potential tissue damage, causes a withdrawal reflex
nociceptors
pain receptors, small sensory fibers called free nerve endings
myelinated A-delta fibers
fast pain system, transmits sharp but short-lived pain of an immediate injury
unmyelinated C-fibers
slow pain system, transmit long-lasting throbbing pain of an injury, decreases as a wound heals
substance P
pain enhancer produced by C-fibers, stimulates free nerve endings at an injury site
gate-control theory
theory of pain, the brain regulates pain by sending signals to the spinal cord to either close or open fates (pathways) to reduce or intensify pain
endorphins and enkephalins
the body’s natural pain killers, inhibit the transmission of pain signals like substance P in the brain and spinal cord
phantom limb pain
the experience of pain in an amputated limb
sensitization
pain pathways become more responsive over time and can occur in the absense of sensory input (chronic pain), the opposite of sensory adaptation
kinesthetic sense
the sense of the location and position of body parts in relation to eachother
proprioceptors
specialized sensory neurons in muscles and joints, communication information to the brain about changes in the body’s position, communicated kinesthetic sense
vestibular sense
the sense of balance, gravity, motion, and body position, sensed by fluid-filled semicircular canals and vestibular sacs in the ears
perception
making sense of sensory data by organizing, interpreting, or relating it to existing knowledge
bottom-up processing
aka data-driven processing,, puts together sensory data to build a full image, part -> whole
top-down processing
aka conceptually driven processing, draws from knowledge and experience to make meaningful perceptions of sensory information, whole -> part
Gestalt Psychology
school of psychology, said that we perceie whole objects or figures (gestalts) instead of isolated pieces of sensory info
extrasensory perception
the detection of information without perception, (eg telepathy, clairvoyange, psychokinesis, precognition), explained by coincidence and the fallacy of positive instances
fallacy of positive instances
the tendency to remember coincidental events
parapsychology
the scientific investigation of claims or paranormal phenomena
figure-ground relationship
we automatically separate figures (main elements) from their grounds (backgrounds), because neurons that respond to the shapes of figures don’t respond to the same shape in the background
figure-ground reversal
the perception of an image in 2 different ways, the vase-face illusion for example
perceptual grouping
the way we actively organize elements to try to produce a stable perception that is a well-defind, whole object
law of Pragnanz
aka law of simplicity, while several perceptual organizations of visual elements are possible, the ones that occurs makes the most stable shape
depth perception
our ability to perceive the distance and 3D characteristics of an object
monocular cues
distance or depth cues that can be processed using only 1 eye
relative size
a monocular cue: if 2 objects are assumed to be of similar size, the one that appears larger is closer
overlap
a monocular cue: a partially blocked object is farther away
aerial perspective
a monocular cue: objects that are blurred by the atmosphere are farther away
texture gradient
a monocular cue: the texture of a surface becomes less distinct the farther away it gets
linear perspective
a monocular cue: the closer parallel lines are, the farther back they go
motion parallax
a monocular cue: in motion, nearby objects zip away faster than distant objects that appear to move slower
relative size, overlap, aerial perspective, texture gradient, linear perspective, motion parallax
the 6 monocular cues
accommodation
the lens flattens or thickens as it focuses on distant or nearby objects, information from eye muscles contribute to perception
binocular cues
distance or depth perception using information from both eyes
convergence
the degree to which muscles rotate your eyes to focus on an object
binocular disparity (aka retinal disparity)
when the retinal image of both eyes differ because an object is very close
stereogram
an image that uses binocular disparity to create the perception of a 3D image
speed perception
based on the estimated rate or enlargenment as an object comes towards us
induced motion
we perceive that the smaller of 2 overlapping objects is moving even if the large one is moving, (top-down processing)
stroboscopic motion
an illusion of apparent motion that occurs when a light briefly flashes an image at one location, followed by another light briefly flashing a similar image at a second location
perceptual constancy
we perceive familiar objects as constant despite change in sensory input to promot a stable view of the world
size constancy
the perception that an object stays the same size despite its changing image on the retina
shape constancy
the perception that an object stays the same shape despite its changing image on the retina
perceptual illusion
the misperception of true charactertistics of an object or image
Muller Lyer Illusion
uses size constancy (the same retinal images but perceived distnace makes an object seem larger) to make lines that are the same length seem longer or smaller
Moon Illusion
the moon appears larger at the horizon because there are many more visual cues that overlap the moon and make it seem farther away, the brain then uses size constancy to infer that farther away objects are larger
perceptual set
the tendency to perceive objects or situations from a particular reference frame
carpentered-world hypothesis
people living in industrial environments perceive lines more and therefore are more susceptible to the Muller-Lyer Illusion
