Unit 4- Sensation And Perception Flashcards
Sensation
The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment
Prosopagnosia
Face blindness- sensation is fine but her perception is off (Heather Sellers)
Perception
The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events
Bottom-up processing
Analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information
Top-down processing
Information processing guided by higher level mental processes, as when we construct perceptions drawing on our experience and expectations
Selective attention
The focusing of conscious awareness on a particular stimulus
Cocktail party affect
Ability to attend to only one voice among many
Inattentional blindness
Failing to see visible objects when our attention is directed elsewhere
Change blindness
Failing to notice changes in the environment (giving directions, change people)
There is also change deafness–not noticing change in voices
Choice blindness
We fail to notice when we are presented with something different than what we want/choose and we come up with reasons to defend that choice
Pop-out phenomenon
We don’t choose to attend to these stimuli, they draw our eye and demand our attention
Psychophysics
The study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them
Absolute threshold
- Gustav Fechner studied our awareness of faint stimuli and called them our absolute threshold
- the minimum stimulation needed to detect a particular stimulus 50% of the time
Subliminal stimuli
Stimuli we detect less than 50% of the time
Signal detection theory
A theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes their is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivations, and alertness
Subliminal
Below one’s absolute threshold for conscious awareness
Priming
The activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response
Difference threshold (just noticeable difference)
The minimum difference between two stimuli required for detection 50% of the time
Weber’s law
The principle that, to be perceived as different, two stimuli must differ by a constant percentage (rather than a constant amount)
Sensory adaptation
Diminished sensitivity as a consequence of constant stimulation
Jumpy eye
Sights don’t vanish because our eyes are always moving, gaze jumps from one spot to another every third of a second
Transduction
Conversion of one form of energy into another (transform). In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret
Electromagnetic spectrum
Ranges from short waves of gamma rays (violet), to the narrow band we see as visible light, to the long waves (red) of radio transmission
Wavelength
The distance from the peak of one light or sound wave to the peak of the next
Hue
The dimension of color that is determined by the wavelength of light; what we know as the color names, blue, green, and so forth
Intensity
The amount of energy in a light or sound wave, which we perceive as brightens or loudness. As determined by the wave’s amplitude
Cornea
Light enters the eye through the cornea, which protects the eye and bends light to provide focus
Pupil
Light then enters the pupil, which is the small, adjustable opening in the center of the eye thought which light enters
Iris
Surrounds the pupil, a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening
The iris dilates or constricts in response to light intensity and inner emotions
Lens
The transparent structure behind the pupil that changes shape to help focus images on the retina
Retina
The light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information
The retina doesn’t see a whole image, the brain reassembles the pieces into a whole upright image
Accommodation
The process by which the eye’s lens changes shape to focus near or far objects on the retina
Rods
Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don’t respond
Cones
Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions, they detect fine detail and give rise to color sensations
Optic nerve
The nerve that carries neural impulses from the eye to the brain (thalamus receives and redistributes info)
Blind spot
The point at which the optic nerve leaves the eye, creating a blind spot because no receptor cells are located there
Fovea
The central focal point in the retina, around which the eye’s cones cluster (detail)
Feature detectors
Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement
Supercell clusters
Teams of cells that integrate info and fire only when cues collectively indicate the direction of someone’s attention and approach
Parallel processing
The processing of many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions, including vision
Contrasts with step-by-step serial processing of computers and conscious problem solving
Blindsight
A localized area of blindness in part of their field of vision as result of stroke or surgery damage
Young-Helmholtz trichromatic (three-color) theory
The theory that the retina contains three different color receptors (one most sensitive to red, one to green, one to blue) which when stimulated in combination can produce the perception of any color
Afterimage effect
See opponent colors when look at certain color combinations for a certain amount of time
Color deficient Vision
Their vision is monochromatic or dichromatic
Opponent-process theory
The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision
Some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green
Audition
The sense or act of hearing (highly adaptive)
Amplitude of sound waves
Strength of sound waves that determines their loudness
Frequency
The number of complete wavelengths that pass a point in a given time (for example, per second)
Pitch
Determined by frequency, a tone’s experienced highness or lowness
Long waves have low frequency and low pitch
Short waves have high frequency and high pitch
Decibels
Measurement of sound, every ten decibels corresponds to a tenfold increase in sound intensity
Outer ear
Channels sound waves through the auditory canal to eardrum
Eardrum
Tight membrane that vibrates with sound waves
Middle war
The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window
Cochlea
A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses
Inner ear
The innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs
Basilar membrane
Ripples in this membrane cause hair cell movement which triggers impulses in the nerve cells, whose axons converge to form auditory nerve, which sends neural messages to auditory cortex
Place theory
Hermann Von Helmholtz’s hearing theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated (explains high-pitched sounds)
Frequency theory
In hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense it’s pitch (explains low-pitched sounds)
Volleyball principle
Neural cells can alternate firing, by firing in rapid succession, they achieve a combined frequency above 1000 waves per second
Conduction hearing loss
Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea (if eardrum is punctured or tiny bones lose their ability to vibrate)
Sensorineural hearing loss
Hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve; also called nerve deafness
Cochlear implant
A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea
Rubber-hand illusion
Researcher simultaneously touches a fake and real (hidden) hand, the volunteer feels as if the fake hand is their own
Kinesthesis
The system for sensing the position and movement of individual body parts
Vestibular sense
The sense of body movement, and position, including the sense of balance
Novice pried
Sensory receptors that detect hurtful temperatures, pressure, and chemicals
Gate-control theory
The theory that the spinal cord contains a neurological gate that blocks pain signals or allows them to pass on to the brain. The gate is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by informations coming from the brain
Taste
Chemical sense, each younger bump has 200 or more taste buds, their pores catch food chemicals
Sweet taste
Indicates energy source
Salty taste
Indicates sodium essential to physiological processes
Sour taste
Indicates potentially toxic acid
Bitter taste
Indicates potential poisons
Umami taste
Indicates proteins to grow and repair tissue
Sensory interaction
The principle that one sense may influence another, as when the smell of food influences it’s taste
McGurk Effect
If we hear a speaker say one syllable while we see another being said, we percieve a 3rd syllable that blends both inputs
Synaesthesia
The senses become joined and one sort off sensation (such as hearing a sound) produces another (such as seeing color)
Smell
Chemical sense, molecules of substance carried in the air reach a tiny cluster of receptor cells at the top of each nasal cavity
Bypass the brain’s sensory switchboard (the thalamus)
Anosmia
Unable to smell
Gestalt
An organized whole. Gestalt psychologists emphasized our tendency to integrate pieces if information into meaningful wholes
Figure-ground
The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)
Grouping
The perceptual tendency to organize stimuli into coherent groups
Proximity
Grouping nearby figures together
Similarity
Grouping similar figures/shapes together
Continuity
Grouping and perceiving continuous patterns
Connectedness
Grouping and perceiving things as uniform and linked
Closure
Grouping where we fill in gaps to complete an image
Depth perception
The ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance
Visual cliff
Gibson and walk- a laboratory device for testing depth perception in infants and young animals
Binocular cues
Depth cues, such as retinal disparity, that depend on the use of two eyes
Retinal disparity
A binocular cue for perceiving depth by comparing images from the retinas in the two eyes, the brain computes distance- the greater the disparity (difference) between the two images, the closer the object
Monocular cues
Depth cues, such as interposition and linear perspective, available to either eye alone
Horizontal-vertical illusion
Perceive vertical dimensions as longer than identical horizontal dimensions (St. Louis Gateway Arch)
Relative height
We perceive objects higher in our field of vision as farther away
Relative size
Perceive object that casts smaller retinal image as farther away
Interposition
If one object partially blocks view of another, we perceive it as closer
Linear perspective
Parallel lines appear to converge with distance
Relative motion
As we move, objects that are actually stable may appear to move as well
Light and shadow
Nearby objects reflect more light thus the dinner object seems farther away
Stroboscopic movement
Brain perceives continuous movement in rapid series of slightly varying images
Phi phenomenon
An illusion of movement created when two or more adjacent lights blink on and off in quick succession
Perceptual constancy
Perceiving objects as unchanging (having consistent shapes, size, lightness, and color) even as illumination and retinal images change
Shape constancy
We perceive the form of familiar objects as constant even as retinal image changes
Size constancy
We perceive objects as having a constant size, even while our distance from them varies
Moon illusion
Cues to objects’ distances make horizontal moon appear larger than moon high in the night sky
Ponzo illusion
Human mind judges an objects’ size based on its background and monocular cues
Ames illusion
Distorted room (trapezoidal)
Lightness (brightness) constancy
We perceive an object as having a constant lightness even when illumination varies
Relative luminance
The amount of light an object reflects relative to its surroundings
Color constancy
Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
Perceptual adaptation
In vision, the ability to adjust to an artificially displaced or even inverted visual field
Perceptual set
Our experiences, assumptions, and expectations give it to us
A mental predisposition to perceive one thing and not another
Extrasensory perception (ESP)
The controversial claim that perception can occur apart from sensory input; includes telepathy, clairvoyance, and precognition
Parapsychology
The study of paranormal phenomena, including ESP and psychokinesis
Telepathy
Mind-to-mind communication
Clairvoyance
Perceiving remote events-friends house is on fire
Precognition
Perceiving future events
Psychokinesis
“Mind over matter” levitating a table or influencing the roll of a die
