Chapter 5: Sensation Flashcards
Perception
The process of organizing & interpreting sensory info, enabling us to recognize meaningful objects & events.
Sensation
The process by which our sensory receptors & nervous system receive & represent stimulus energies from our environment.
Bottom-up processing
Analysis that begins with the sensory receptors & works up to the brain’s integration of sensory info.
Top-down processing
Info processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience & expectations.
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 needed to detect a particular stimulus 50% of the time. (Light, sound, pressure, taste or odor)
Signal detection theory
A theory predicting how & when we detect the presence of a faint stimulus (“signal”) amid background stimulation (“noise”). Assumes there is no single absolute threshold & that detection depends partly on a person’s experiences, expectations, motivation & level of fatigue.
Subliminal
Below one’s absolute threshold for consciousness awareness.
Priming
The activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory or response.
Difference threshold
The minimum difference between 2 stimuli required for detection 50% of the time. We experience the difference threshold as a just noticeable difference.
Weber’s Law
The principle that to be perceived as different, 2 stimuli must differ by a constant minimum percentage (rather than a constant amount)
Sensory adaption
Diminished sensitivity as a consequence of constant motion.
Transduction
Encode physical energy as neural signals.
Wavelength
The distance from the peak of one light or soundwave to the peak of the next
Hue
The dimension of color that is determined by the wavelength of light
Intensity
The amount of energy in a light or soundwave, which we perceive as brightness of loudness, as determined by the wave amplitude.
Pupil
The adjustable opening in the center of the eye through which light enters.
Iris
A ring of muscle tissue that forms the colored portion of the eye around the pupil & controls the size of the pupil opening.
Lens
The transparent structure behind the pupil that changes shape to help focus images on the retina.
Accommodation
The process by which the eye’s lens changes shape to help focus images on the retina.
Retina
The light-sensitive inner surface of the eye, containing the receptor rods & cones plus layers of neurons that begin processing visual info.
Acuity
The sharpness of vision
Nearsightedness
Nearby objects are seen more clearly than distant objects because distant objects focus in front of the retina.
Farsightedness
Faraway objects are seen more clearly than near objects because the image of near objects is focused behind the retina.
Rods
Retinal receptors that detect black, white & gray; necessary for peripheral & twilight vision, when cones don’t respond.
Cones
Retinal receptor cells that are concentrated near the center of the retina & that function in daylight or in well-lot conditions. The cones detect fine detail & 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; the brain’s natural mode of info processing for many functions.
Blindsight
Blindness in part of the field of vision due to destruction in the visual cortex - from a stroke or surgery.
Young-helmholtz trichromatic (three-color) theory
The theory that the retina contains 3 different color receptors - red, green & blue - that when stimulated in combinations 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.
Color constancy
Perceiving familiar objects as having consistent color, even in changing illumination alters the wave-lengths reflected by the objects
Audition
The sense or act of hearing
Frequency
The # of complete wavelengths that pass a point in a given time
Pitch
A tone’s experienced highness or lowness, depends on frequency.
Middle ear
The chamber between the eardrum & cochlea, containing 3 tiny bones (hammer, anvil & 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 & vestibular sacs.
Place theory
In hearing, the theory that links the pitch we hear with the place the cochlea’s membrane is stimulated.
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.
Conduction hearing loss
Hearing loss caused by damage to the mechanical system that conducts sound waves to cochlea.
Sensorineural hearing loss
Hearing loss caused by damage to the cochlea’s receptor cells to the auditory; also called nerve deafness.
Cochlear implant
Device for converting sounds into electrical signals & stimulating the auditory nerve through electrodes threaded into the cochlea.
Sensory interaction
The principle that one sense may influence another, as when the smell of food influences its taste.
Kinesthesis
The system for sensing the position & movement of individual body parts.
Vestibular sense
The sense of body movement & position, including the sense of balance.
Olfaction
Sense of smell
Synesthesia
The phenomenon where the senses become joined. (Hear a sound, see a color)
Prosopagnosia
Impairment in the recognition of faces
Bipolar cells
Transmits signals from the photoreceptors to the ganglion cells.
Ganglion ces
Receives visual info from photoreceptors via 2 intermediate neuron types: horizontal cells & ampicrine cells
Cilia
Tiny hairs lining the cochlea
Gate-control theory
Pain asserts that non-painful input closes the “gates” to painful input, which prevents pain sensation from traveling to the central nervous system. Therefore, stimulation by non-noxious input is able to suppress pain
McGurk Effect
Phenomenon that demonstrates an interaction between hearing and vision in speech perception. The illusion occurs when the auditory component of one sound is paired with the visual component of another sound, leading to the perception of a third sound.
