| the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. | sensation |
| the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events. | perception |
| analysis that begins with the sense receptors and works up to the brain’s integration of our sensory information. | bottom-up processing |
| information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations. | top-down processing |
| the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them | psychophysics |
| the minimum stimulation needed to detect a particular stimulus 50% of the time | absolute threshold |
| a theory predicting how and when we detect the presence of a faint stimulus (“signal”) amid background stimulation(“noise”) | signal detection theory |
| below one’s absolute threshold for conscious awareness | sublimial |
| the activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response | priming |
| the minimum difference between two stimuli required for detection 50% of the time. | difference threshold |
| the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount) | Weber's Law |
| diminished sensitivity as a consequence of constant stimulation | sensory adaptation |
| conversion of one form of energy into another. In sensation, the transforming of stimulus energies into neural impulses. | transduction |
| the distance from the peak of one light or sound wave to the peak of the next | wavelength |
| the dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, and so forth | hue |
| the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave’s amplitude | intensity |
| the adjustable opening in the center of the eye through which light enters. | 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 | iris |
| the transparent structure behind the pupil that changes the shape to help focus images on the retina | lens |
| the process by which the eye’s lens changes shape to focus near or far objects on the retina | accomodation |
| 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 | retina |
| the sharpness of vision | acuity |
| a condition in which nearby objects are seen more clearly than distance objects because distant objects focus in front of the retina | nearsightedness |
| a condition in which faraway objects are seen more clearly than nearby objects because the image of near objects is focused behind the retina | farsightedness |
| retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don’t respond. | rods |
| receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. Detect fine detail and give rise to color sensations. | cones |
| the nerve that carries neural impulses from the eye to the brain. | optic nerve |
| the point at which the optic nerve leaves the eye. | blind spot |
| the central focal point in the retina, around which the eye’s cones cluster. | fovea |
| the processing of several aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions, including vision. Contrasts with the step-by-step processing of most computers and of conscious problem solving. | parallel processing |
| 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. | Young-Helmholtz trichomatic theory |
| the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. | opponent process theory |
| perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object | color constancy |
What is the difference between Weber's law and difference threshold?
The just noticeable difference, also known as the difference threshold, is the smallest possible difference between two stimuli that can be detected at least half the time. According to Weber's law, this difference threshold is a constant proportion of the original threshold size.
Which of the following describes Weber's law?
Correct answer: The just-noticeable difference between any two stimuli is proportional to the magnitude of those stimuli. Explanation: Weber's law states that the just-noticeable difference between any two stimuli is proportional to the magnitude of those stimuli.
What percentage of time must we be able to detect a stimulus for it to be our absolute threshold for that stimulus?
The absolute threshold is the minimum amount of stimulation required for a person to detect the stimulus 50 percent of the time.
Who developed both the two point threshold and the concept of the just noticeable difference?
Found by Ernst Weber, "the threshold at which two points of stimulation can be distinguished as such."