AP psych Unit 4

Sensation

Sensation

the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

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

Inattentional blindness

failing to see visible objects when our attention is directed elsewhere

Change blindness

failing to notice changes in the environment

Transduction

conversion of one form of energy into another

Psychophysics

the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

Absolute threshold

the minimum stimulation necessary to detect a particular stimulus 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)

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

the minimum difference between two stimuli required for detection 50 percent of the time - just noticeable difference (jnd)

Weber’s Law

the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)

Sensory Adaptation

diminished sensitivity as a consequence of constant stimulation

Perceptual set

a mental disposition to perceive one thing and not another

Extrasensory Perception (ESP)

the controversial claim that perception can occur apart from sensory input

Parapsychology

the study of paranormal phenomena, including ESP and psychokinesis

Wavelength

the distance from the peak of one light or sound wave to the peak of the next

Intensity

the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave’s amplitude

Hue

the dimension of color that is determined by the wavelength of light

Cornea

outer covering of the eye

Pupil

adjustable opening in the center of the eye through which light enters

Iris

ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

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

Accommodation

process by which the eye’s lens changes shape to focus near or far objects in 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; Function in daylight/well-lit conditions; Detect fine detail and give rise to color sensations

Optic nerve

the nerve that carries neural impulses from the eye to the brain

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

Feature detectors

nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement

Parallel processing

the processing of many aspects of a problem simultaneously

Young-Helmholtz trichromatic (three color) theory

the theory that the retina contains three different color receptors (red, green, blue) which, when stimulated in combination can produce the perception of any color

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)

Gestalt

an organized whole

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, Continuity, and Closure

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

a laboratory device for testing depth perception in infants and young animals

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 between the two images, the closer the object)

Binocular cues

depth cues (ex. retinal disparity) that depend on the use of two eyes

Monocular cues (definition)

depth cues (ex. interposition, linear perspective) available to either eye alone

Monocular cues (examples)

Relative height, Relative size, Interposition, Linear perspective, Relative motion, and Light and shadow

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

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

Audition

the sense or act of hearing

Pitch

a tone’s experienced highness or lowness (depends on frequency)

Amplitude of sound waves

determines their loudness

Frequency

the number of complete wavelengths that pass a point in a given time (i.e. per second)

Eardrum

tight membrane that vibrates when struck by sound waves

Middle ear

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

Oval window

where the stirrup connects to the cochlea

Cochlea

a coiled, body, 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

Auditory nerve and Auditory cortex

Auditory nerve

nerve which sends the auditory message to the brain via the thalamus

Sensorineural hearing loss

loss caused by damage to the cochlea’s receptor cells or to the auditory nerves (aka nerve deafness)

Conduction hearing loss

hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea

Cochlear implant

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea

Place theory

in hearing, the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated (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 its pitch (low pitched sounds); Volley principle

Types of touch

Pressure, Warmth, Cold, and Pain

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

Nociceptors

a sensory receptor for painful stimuli

types of taste

Sweet, sour, salty, bitter, and Umami (savory)

sweet

energy source

salty

sodium essential to physiological processes

sour

potentially toxic acid

bitter

potential poisons

umami

proteins to grow and repair tissue

Olfaction (smell)

Chemical sense, Odor molecules, Olfactory bulb, and Olfactory nerve

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 (semicircular canals)

Sensory interaction

the principle that one sense may influence another, as when the smell of food influences its taste

Embodied cognition

in psychological science, the influence of bodily sensations, gestures, and other states of cognitive preferences and judgments

Volley Principle

Hearing things at a high frequency