Mod 17 & 18 Flashcards
sensation
the process by which our sensory reeptors 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
psychophysics
the study of relationships beetween 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 percent 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 there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness
subliminal
below one’s absolute threshold for conscious awareness
priming
the activation, often unconsciously, of certain associations, thus pre-disposing one’s perception, memory, or response
difference threshold
the minimum difference between two stimuli required for detection fifty percent of the time. We experience the difference threshold as a just noticeable difference(ind)
Weber’s law
the principle that, to be perceived as dfferent, 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, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret
wavelength
the distance from the 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
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 brightness or loudness, as determined by the wave’s 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 and controls the size of the pupil opening
lens
the transparent struture 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
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 recpetor cells that are concentrated near the cneter of the retina and that function in daylight or in well lit conditions. the cones detect fine detail and give rise to color sensations
optic nerve
the nerve that carries neural impulses from eh eye to 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 brainthat 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 information processing for many functions, including vision. Contrasts with the step by step-serial processing of most computers and f conscious problem solving
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
opponent-process theory
the theory that opposing retinal processes(red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhbited by red’ others are stimulated by red and inhibited by green
