Term
| Just Noticeable Difference (JND) |
|
Definition
| Fechner: The smallest possible difference between two stimuli that an organism can reliably detect. Describes an observer's ability to discriminate. |
|
|
Term
|
Definition
| The observation that the size of the difference threshold is proportional to the intensity of the standard stimulus. |
|
|
Term
|
Definition
In Weber's Law, the fraction given by the change in stimulus intensity (Δ I) divided by the standard intensity (I) required to produce a just noticeable difference. ΔI / I = C |
|
|
Term
|
Definition
| the assertion that the strength of a sensation is proportional to the logarithm of a physical stimulus intensity. S = k log I. |
|
|
Term
|
Definition
| the theory that the act of perceiving or not perceiving a stimulus is actually a judgment about whether a momentary sensory experience is due to background noise alone or to the background noise plus a signal. The theory also includes a procedure for measuring sensory sensitivity. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the participant is guided by her perception of the "payoffs" built into the situation. Will the experimenter think she is insensitive or uncooperative is she misses any of the signals? |
|
|
Term
|
Definition
Sensory coding is the process through which the nervous system represents the qualities of the incoming stimulus -- whether auditory of visual or red light or a green light, a sour taste or a sweet taste. A code is a set of rules through which info. is transformed from one format into another. |
|
|
Term
|
Definition
| the magnitude of a stimulus as it is perceived, not in terms of its physical attributes. (changes in loudness and changes in loudness and brightness) |
|
|
Term
|
Definition
| a distinguishing attribute of a stimulus. ex: brightness, hue, pitch (the difference in the neural code that tells us we are hearing rather than seeing, or tasting something sweet rather than smelling something rotten) |
|
|
Term
| Doctrine of Specific Nerve Energies |
|
Definition
| Johannes Muller: Differences in sensory quality are not caused by differences in the stimuli themselves, but by the different nervous structures that these stimuli excite. Thus, stimulating the retina will produce sensations of light, whether the retina is stimulated by a beam of light or pressure to the eye ball. |
|
|
Term
|
Definition
| an approach to sensory experience which asserts that different sensory qualities are signaled by different neurons. These neurons are somehow labeled with their quality, so that whenever they fire, the nervous system interprets their activation as that particular sensory quality. (Labeled line theory) (nervous system acts as if these quality specific neurons were somehow "labeled" with their quality. |
|
|
Term
|
Definition
| the theory that a stimulus attribute is not coded by being sent along specific sensory fibers, but rather by a specific pattern of firing of all the relevant sensory fibers. |
|
|
Term
|
Definition
| a general term for sensory information generated by receptors in the muscles, tendons, and joints which informs us of our skeletal moveement. |
|
|
Term
|
Definition
three half-circular, interconnected tubes located inside each ear.
* Horizontal semicircular canal; detects rotation of the head around a vertical axis (i.e. the neck), as when doing a pirouette.
* Superior semicircular canal; detects rotation of the head around a rostral-caudal (anterior-posterior) axis, as when cartwheeling.
* Posterior semicircular canal; detects rotations of the head in the sagittal plane, as when nodding. |
|
|
Term
|
Definition
| Vestibular senses are a set of receptors that provide info. about the orientation and movements of the head, located in the semicircular canals and the vestibular sacs of the inner ear. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the process by which the sensitivity to a stimulus declines if the stimulus is continually presented. |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
|
Definition
| successive pressure variations in the air that vary in amplitude and wavelength. |
|
|
Term
|
Definition
| the height of a wave crest, used as a measure of intensity of a sound or light wave. it is determined by the amount of pressure exerted by eah air particle on the next. |
|
|
Term
|
Definition
| the number of wave peaks per second. it governs the perceived pitch of the sound or the perceived hue of the light. |
|
|
Term
|
Definition
| the distance between the crests of two successive waves and the major determinant of pitch or hue. |
|
|
Term
|
Definition
| the psychological dimension of sound that corresponds to frequency. as frequency increases, pitch appears to rise. |
|
|
Term
|
Definition
| the logarithmic units used to describe sound intensity (or amplitude) |
|
|
Term
|
Definition
| (Hz) a measure of frequency in number of cycles per second. |
|
|
Term
|
Definition
| a coiled structure in the inner ear that contains the basilar membrane. |
|
|
Term
|
Definition
| the portion of the ear that includes the ear flap, auditory canal and the outer surface of the eardrum. |
|
|
Term
|
Definition
| the taut membrane that transmits vibrations caused by sound waves across the middle ear to the inner ear. |
|
|
Term
|
Definition
| the tube that carries sound from the outer ear to the eardrum. |
|
|
Term
|
Definition
| the membrane separating the middle ear from the inner ear. |
|
|
Term
|
Definition
| an antechamber to the inner ear which amplifies the sound-produced vibrations of the eardrum and transfers them to the cochlea. |
|
|
Term
|
Definition
| the portion of the ear in which actual transduction of sound takes place. |
|
|
Term
|
Definition
| the three bones of the middle ear that transmit vibrations from the eardrum to the oval window. |
|
|
Term
|
Definition
| deformation by the sound-produced pressure stimulates the auditory receptors. |
|
|
Term
|
Definition
| a theory of pitch proposed by Hermann von Helmholtz which states that different regions of the basilar membrane respond to different sound frequencies. the nervous system interprets the excitation from different basilar regions as different pitches. |
|
|
Term
|
Definition
| the proposal that the perception of a tone's pitch is coded by the rate of firing of neurons in the auditory system. this is probably correct for the perception of lower pitches but certainly false for higher pitches. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the range of wavelengths to which our visual system can respond. 400 nanometers (violet) to 750 nanometers (reddish orange) |
|
|
Term
|
Definition
| the eye's transparent outer coating. |
|
|
Term
|
Definition
| visual-pigment-filled light-sensitive cells at the back of the retina. Rods or Cones. theses are the cells that transduce light energy into neural impulses, launching the processes of vision. |
|
|
Term
|
Definition
| the portion of the eyes that bends light rays and thus can focus an image on the retina. |
|
|
Term
|
Definition
| the process by which the lens is thickened or flattened to focus on a subject. |
|
|
Term
|
Definition
| photoreceptors in the retina that respond to lower light intensities and give rise to achromatic sensations. |
|
|
Term
|
Definition
| visual receptors that respond to greater light intensities and give rise to chromatic sensations. |
|
|
Term
|
Definition
| the area of the retina on which an image falls when the viewer is looking directly at the source of the image. acuity is greater when the image falls on the fovea than when it falls on any other portion of the retina. |
|
|
Term
|
Definition
| the bundle of fibers that proceeds from each eyeball to the brain. made up of axons whose cell bodies are retinal ganglion cells. |
|
|
Term
|
Definition
| the region of the retina that contains no visual receptors and therefore cannot produce visual sensations. (where it meets the optic nerve) |
|
|
Term
|
Definition
| the theory that rods and cones handle different aspects of vision. the Rods are receptors for night vision; they operate at low light intensities and lead to achromatic sensations. the Cones are used in day vision; they respond at higher illumination levels, have greater acuity and are responsible for sensations of color. |
|
|
Term
|
Definition
| colors, such as black white and natural grays, that do not have the property of hue. |
|
|
Term
|
Definition
| the ability to distinguish between separate points projected on the retina. It is greatest in the fovea, where the receptors are closely bunched together. |
|
|
Term
|
Definition
| the pattern of a receptor's or pigment's reactions to different wavelengths of light. |
|
|
Term
|
Definition
| the chemical inside a photoreceptor that, when exposed to light, changes form, thus releasing some energy and triggering a neural impulse. the chemical is then restored to its original form so that it becomes ready to respond to the next bit of incoming light. |
|
|
Term
|
Definition
| the photo pigment used in the rods within the retina. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| the perceivers tendency to exaggerate the physical difference in the light intensities of two adjacent regions. as a result, a gray path looks brighter on a black background, darker on a white background. |
|
|
Term
|
Definition
| the accentuated edges between two adjacent regions that differ in brightness. this sharpening is maximal at the borders where the s distance between the two regions is smallest and the contrast more striking. |
|
|
Term
|
Definition
| the tendency of adjacent neural elements of the visual system to inhibit each other; it underlies brightness contrast and the accentuation of contours. |
|
|
Term
|
Definition
a perceived dimension of visual stimuli whose meaning is close to the term color (ex: red, blue) the property of wavelengths of light known as color; different wavelengths correspond to our subjective experience of different colors. |
|
|
Term
|
Definition
| colors that have a discernible hue. colorful |
|
|
Term
|
Definition
| a perceived dimension of visual stimuli that describes the "strength" of a color. the extent to which it appears rich or pale. (light pink vs. hot pink) |
|
|
Term
|
Definition
| when an artist mixes pigments or when color filters are placed on top of each other, each pigment or filter absorbs its own set of wavelengths and the only wavelengths that emerge are the ones not absorbed by any of the pigments of filters. each pigment of filter "subtracts" its set of wavelengths from the initial set and the perceived color depends on what is left over after the subtraction. (a subtractive mixture of 3 different colors produces gray) |
|
|
Term
|
Definition
| when lights are mixed together, each light contributes its own wavelengths and the resulting mix can be thought of as the "sum" of these contributions. (a mixture of appropriately chosen colors produces white) |
|
|
Term
|
Definition
| color vision occurs through the operation of three sets of cones, each maximally sensitive to a different wavelength of light. red blue and green |
|
|
Term
|
Definition
| a theory of color vision which holds that each of the three receptor types (short wave, medium wave and long wave) gives rise to the experience of one basic color (blue, green or red) |
|
|
Term
|
Definition
| a visual experience that occurs after the original source of stimulation is no longer present. |
|
|
Term
| Simultaneous Color contrast |
|
Definition
| the effect produced by the fact that any region in the visual field tends to induce its complementary color in adjoining areas. Ex: a gray patch will tend to look blueish if surrounded by yellow and yellowish if surrounded by blue |
|
|
Term
|
Definition
| in color vision, the persistence of an image that possesses that hue complementary to that of the stimulus resulting from the operation of opponent processes. Ex: Seeing a yellow afterimage after staying at a blue lamp. |
|
|
Term
|
Definition
| a theory of color vision that proposes three pairs of color antagonists: red-green, blue-yellow and white-black. Excitation of one member of a pair automatically inhibits the other member. |
|
|
Term
|
Definition
| deficiencies in color vision. red-green color blindness. |
|
|
Term
|
Definition
| the retinal area in which visual stimulation affects a particular cell's firing rate. |
|
|
Term
|
Definition
| neurons in the retina or brain that respond to specific features of a stimulus, such as moment, orientation. |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| After effect of visual movement |
|
Definition
|
|
