Sensation and Perception Flashcards
Ernst Weber
1834, De Tactu, investigation of muscle sense, just noticeable difference (jnd) in sensation
Gustav Fechner
relatinoship between physical stimuli and psychological responses to stimuli, Weber’s Law
Weber’s Law
mathematical expression of Weber’s discovery about just noticeable differences - states that the change in stimulus intensity needed to produce a jnd divided by the stimulus intensity of the standard stimulus is a constant, fits data except at very low and very high intensities
Sir Francis Galton
one of the first researchers interested in individual differences, measured sensory abilities of nearly 10,000 people
Max Wertheimer (1880-1943
Gestalt psychology founder, phi phenomenon
Absolute threshold
minimum of stimulus energy that is needed to activate a sensory system
Limen
threshold
Subliminal perception
perception of stimuli below a threshold
Difference threshold
how different two stimuli must be before they are perceived to be different
Just noticeable difference
amount o fchange necessary to predict the difference between two stimuli
Fechner’s law
relationship between ntensity of sensation and intensity of hte stimulus, derived from Weber’s law, sensation increases more slowly as intensity increases
Steven’s power Law
relates intensity of the stimulus to the intensity of the sensation 20th century, suggested Fechner’s law might be incorrect
Signal detection theory
other, nonsensory factors influence what the subject says she senses including experiences, motives and expectations
Response Bias
refers to the tendency of subjects to respond in a particular way due to nonsensory factors
Receiver operating characteristic (ROC)
employed by many researchers to graphically summarize a subject’s responses by measuring hte operating (sensitivity) characteristics of a subject receiving signals
John A. Swets
refined the use of ROC curves
Transduction
translation of physical energy into neural impulses or action potentials, electrochemical energy is sent to various projection areas in the brain along with various neural pathways to be processed in the nervous system
Cornea
clear domelinke window int he front of the eye, gathers and focuses the incoming light
Pupil
hole in the iris contracts in bright light and expands in dim light to let mroe likght in
Iris
colored part of the eye, has involuntary muscles and autonomic nerve fibers, controls size of pupil and amount of light entering the eye
Lens
lies right behind the iris helps control the curvature of the light coming in and can focus near or distant onjects on the retina
Retina
back of the eye and like a screen filled with neural elements and blood vessels, image-detecting part of the eye
Duplexity/Duplicity theory of vision
retina contains two kinds of photoreceptors, organization of retinal cells makes light pass through intermediate sensory neurons before reaching and stimulating the photoreceptors
Rods
best in reduced illumination, perception of only achromatic coors, low sensitivity to detail and are not involved in color vision
Cones
color vision, perceiving fine detail, most effective in bright light and allow us to see chromatic and achromatic colors
Fovea
contains only cones, middle of the eye - as you move farther away less cones
bipolar neurons
connect rods and cones and ganglion cells
Ganglion Cells
connect bipolar neurons and form optic nerve, each cell represents combined imput of many rods and cones, loss of detail as information from the photorecepters is combined
Optic Chiasm
fibers from the nasal half of the retina cross paths
Lateral geniculate nucleus
part of the thalumus, used for vision
Used for vision
lateral geniculate nucleus of the thalamus, visual cortex in the occipital lobe, superior colliculus
Feature Detection Theory
Hubel and Wiesel figured out the neural basis in 1981 using single cell recording, certain cells in the cortex are maximally sensitive to certain features of stimuli, simple, complex, and hypercomplex cells
Simple Cells
Feature Detection Theory, information about orientation and boundaries of an object
Complex Cells
Feature Detection Theory, information about orientation such as movement
Hypercomplex Cells
Feature Detection Theory, abstract concepts such as object shape
Illumination
physical, objective measurement that is simply the amount of light falling on a surface
Brightness
subjective impression of the intensity of a light stimulus
Rhodopsin
photochemical in the rods, made up of vitamin A derivative, called retinal and a protein called opsin, bleached when
Bleaching
When a molecule of rhodopsin absorbs a photon of light, the pigment begins to decompose, or split, into retinene and opsin – takes time for pigments to regenerate
Simultaneous brightness contrast
a target area of a particular luminance appears brighter when surrounded by a darker stimulus than when surrounded by a lighter stimulus
Lateral inhibition
explanation for simultaneous brightness contrast, adjacent retinal cells inhibit one another, if a cell is exhited, other ones around it will be inhibited - sharpens and highlights borders between dark and light
Dark Adaptation
regeneration of rhodopsin, the photopigment in the rods allowing you to see in the dark, requires vitamin A
Color perception
wavelength of light entering the eye (400 - 800 nanometers for humans)
Subtractive color mixture
mix pigments
Additive color mixing
red and green lights give you yellow, blue green and red are the primary colors
Young-Helmotz Theory/Trichormatic thoery
retina contains three different types of color receptors (cones) which are differentially sensitive to different colors, one maximally sensitive to red, one to blue, and one to free, all colors are produced by combined stimulation, ratio of stimulation that determines color
Ewald Herings’s criticism of trichromatic theory/opponent-process theory of color vision
yellow must be a primary color along with red blue and green, arranged in opposing pairs, including black white
Afterimages
inspired Hering’s theory - appears after prolonged or intense exposure to a stimulus, opposite of original stimulus
George Berkeley 1709
listed various cues for depth
Interposition/Overlap
cue for depth perception when one object covers or overlapes with another
Relative Size
cue for dept perception, as an object gets farther away its image on the retina gets smaller
Linear Perspective
convergence of parallel lines in teh distance
Texture gradients
depth cue, JJ Gibson, variations in perceived surface texture as a function of distance from the observer, farther away have smaller more densely packed elements
MOtion Parallax
objects closer move in the same direction as you, different speeds as it gets closer to you
Kinetic Depth Effect
object rather than the perceiver moves, the motion of that object gives us cues about relative dept of parts of the object, special kind of motion parallax
Binocular Disparity/Stereopsis/Binocular Depth Cue
depends on the fact that distance between the eyes provides us with two slightly disparate views of the world
Binocular Parallax
degree of disparity bewtween the retinal images of the eyes due to the slight differences in the horizontal position of each eye
figure
perception of form, integrated visual experience that stands out at the center of attention
Ground
background against which the figure appears, perception of form
Law of proximity
elements close to one another tend to be perceived as a unit
Law of similarity
objects taht are similar tend to be grouped together
law of good continuation
elements that appear to follow the same direction tend to be grouped together
Subjective contours
shapes that are not present in the physical stimulus
Law of closure
when a space is enclosed by a contour it tends to be perceived as a figure, certain figures tend to be perceived as more complete than they really are
Law of pragnanz
encompasses the other gestalt laws that explain form perception, says that perceptual organization will always be regular, simple and symmetric as possible
Theory of Isomorphism
Wolfgang Kohler, one-to-one correspondence between teh object int eh perceptual field and the pattern of stimulation in the brain, hasn’t faired well empirically
Bottom up processing
data-driven processing, object perception that responds directly to the components of incoming stimulus on the basis of fixed rules, sums up the componenents to arrive at the whole pattern, such as in feature detection
Top-down processing
object perception that is guided by conceptual processes such as memories and expectations that allow the brain to recognize the whole object and then recognize the componenets
Apparent motion
illusion that occurs when two dots flashed in different locations on a screen seconds apart are perceived as one moving dot (stroboscopic movement)
Induced motion
illusion of movement occurring when everything around the spot of light is moved
autokinetic effect
illusion that occurs when a spot of light appears to move erratically in a dark room simply because there is no frame of reference
motion aftereffect
you first view a moving pattern, such as stripes moving off to the right and then you view a spot of light and the light appears to move in teh opposite direction
distal stimulus
actual object or event out there in the world
proximal stimulus
information our sensory receptors receive about the object
Emmert’s Law
size constancy depends on apparent distance, farther away the object appears to be, the more the scaling device in the brain will compensate for its retinal size by enlarging our perception of the object
Ames Room
difference in distance creates difference in size perceived
Moon illusion
moon on horizon appears larger than at zenith, distance cues
Shape constancy
door is a rectangle no matter if open or closed
Lightness constancy
despite changes in the amount of light falling on an object, apparent lightness remains unchanged
Color constancy
perceived color of an object does not change when we change hte weavelength of the light we see
Illusions
Muller Lyer, Hering, Ponzo, Wundt, Poggendorff
ePreferential Looking
two different stimuli are presented side by side, amount of time spent looking at each is recodrded, if theres a difference it can be inferred that the infant can discriminate between the two stimuli
Habituation
new stimulus is presented to an infant, infant will orient toward it, infant remains disinterested with new stimulus if he cannot differentiate
Visual Cliff
1960s, Eleanor Gibson and Richard Walk, table set up to create the illusion tha thte left half of the table is much lower than the right half, even small infants perceive cliff, do not try and cross
Frequency
number of cycles per second measured in Hz, inversely related to wavelength, human sensitivity is 20 to 20000
Intesnity
amplitude or height of the air pressure waver, measured in bels, tenths of a bel is a decibel, loudness
Timbre
quality of a particiular sound
Pinna
fleshy part of the ear visible from the outside, where sound wave first reaches
Tympanic Membrane
eardrum, vibrates in phase with incoming sound waves, moving back and forth at a high rate for high-frequency sounds and more slowly for low-frequency sounds
Ossicles
tiny bones in middle ear, hammer, anvil and stirrup, malleus, inclus and stapes, transmit vibrations of the tympanum to the inner ear
Oval window
entrance to the inner ear
Cochlea
filled with saltwater like fluid, inner ear
Basilar membrane
in cochlea, organ of Corti which is composed of thousands of hair cells which are receptors for hearing, when the bend electrical signal to nerve fiber to auditory nerve
`Auditory Pathway
auditory nerve to the superior olive to the inferieor colliculus to the medial geniculate nucleus in the thalamus to the temporal cortex
Helmholtz’s Place-Resonance Theory
each different pitch causes a different place on the basilar membrane to vibrate, each causing a different hair cell to bend - tones higher than 4000 hz, 500 to 4000
Frequency theory
basilar membrane vibrates as a whole, rate of bivration equals the frequency of teh stimulus - tones up to 500 hz and up to 4000
Von Bekesy’s Travelling Wave Theory
early 1960s movement of the basilar membrane is maximal at a different place along hte basilar membrane for each different frequency, whole thing vibrates for any given stimulus, high frequencies vibrate close to the oval window, low near the apex or tip of the cochlea
Papillae
taste buds found on these little bumps
olfactory epithelium
holds smell receptors
Smell Information
Ofactory Bulb in brain
Taste information
taste center in thalamus
SOmatosensory cortex
touch, parietal lobe
two-point theory
refers to the minimum distance necessary between two poitns of stimulation on the skin such athat the points will be felt as two distinct stimuli
Physiological zero
temperature is judged relative to temperature of the skin or
Gate theory of pain
Ronal d Melzach, Patric Wall, gating turns pain on and off, spinal cord
Proprioception
sense of boldily position
Vestibular sense
sense of balance and our bodily position relative to gravity inner ear above and behind the cochlea
Kinesthetic sense
awareness of body movement and position, muscle,tendon and joint receptors are at or near them
Donald Broadbent
selective attention acts as a filter between sesnory stimuli and processing systems, all or nothing
dichotic listening
listeneres can listen to one stim and dampen out the thother
