vocabs from Chap. 5: Sensation [David Myer's Psychology book 8th edition]

Chap. 5

• Sensation- process where our sensory receptors and nervous system receive & represent stimulus energies from our environment
• Perception- process of organizing & interpreting sensory info, enables to recognize meaningful objects and events
• Bottom-up processing- analysis that begins with the sensory receptors and works upto the brain’s integration of sensory info. [ex. 1st looking at the details then concluding the object to be something]
• Top-down processing- information processing guided by higher-level mental process, as when we construct perceptions drawing on our experience and expectation [ex. 1st given the object then looking at the details]
• Psychophysics- the study of relationship between the physics characteristics of stimuli, such as intensity, and our psychological experience of them
• Absolute threshold- the minimum stimulation needed to detect a particular stimulus 50% of time
• Difference threshold- the minimum difference between two stimuli required for detection 50% of the time aka JND- just noticeable difference
• Signal detection theory- predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends party on a person’s experience, expectations, motivation, and level of fatigue
• Subliminal- below one’s absolute threshold for conscious awareness
• Prime- activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response
• Weber’s law- 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
• Transduction- conversion of one form of energy into another. In sensation, stimulus energies, such as sights, sounds, smells, are transformed into neural impulses that brains can interpret

VISION
• Wavelength- distance from peak of one light or sound wave to the peak of the next, electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission
• Hue- dimension of color that is determined by the wavelength of light—what we know as color names such as blue and green
• Intensity- the amount of energy in light of sound wave, which we perceive as brightness or loudness, as determined by the waves amplitude
• Pupil- the adjustable opening in the center of the ye 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
• 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
• Lens- the transparent structure behind the pupil that changes shape to help focus images on the retina
• Accommodation- process where eye’s lenses changes shape to help focus image on the retina
• Acuity- sharpness of vision
• Nearsightedness- nearby objects are seen more clearly that distant objects bc distant objects focus in front of the retina
• Farsightedness- far away objects are seen more clearly that nearby objects bc image of near objects is focused behind 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. Detects fine detail and give rise to color sensation
• Optic nerve- carries neural impulses from eye to brain
• Blind spot- point where the optic nerve leaves the eye; no receptor cells are located
• Fovea- central focal point in the retina, around which the eye’s cones cluster
• Parallel processing- brain’s natural mode of information processing for many functions, including vision—contrasts with the step by step processing
• Young-Helmholtz trichromatic theory- says 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
• Opponent-processing theory¬- theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. [ex. Some cells are stimulated by green and inhibited by red, vise versa]
• Color constancy- perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object [ex. Leaf stays green and branch stays brown even though they both reflect the same light energy]

HEARING
• Audition- the sense or act of hearing
• Frequency- number of complete wavelengths that pass a point in a given time [ex.per second]
• Pitch- a tone’s experienced highness or lowness; depends on frequency
• Inner ear- the innermost part of the ear, containing the cochlea, semicircular canals and vestibular sacs
• Cochlea- a coiled, bony, fluid-filled tube in the inner ear where sound waves trigger nerve impulses
• Middle ear- the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, & stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window
• Place theory- presumes that we hear different pitches bc different sound waves trigger activity at different places along the cochlea’s basilar membrane [credit to Hermann von Helmholtz]
• Frequency theory- alternative explanation for how we detect pitch, that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling sense of pitch
• Conduction hearing loss- hearing loss caused by damage to the mechanical sytem that conducts sounds waves to the cochlea
• Sensorineural hearing loss- hearing loss caused by damage to the cochlea’s receptor cell or to the auditory nerves aka nerve deafness
• Cochlear implant- a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea

• Gate-control theory- 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 information coming from the brain
• 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 and movement of individual body parts
• Vestibular sense- sense of body movement and position, including the sense of balance