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S&P Exam 2
| Question | Answer |
|---|---|
| what are the 3 steps to color perception? | detection, discrimination, appearance |
| what are the 3 types of cone photoreceptors? What kind of wavelengths do they detect? | S-cones (short; blue), M-cones (medium; green), and L-cones (long; red) |
| the L-cone's peak sensitivity is 565 nm, which corresponds to ____ not ______? | yellow; red |
| light intensities that are bright enough to stimulate the cone receptors & bright enough to "saturate" the rod receptors to their max responses (ex: sunlight and bright indoor lighting) | photopic |
| light intensities that are bright enough to stimulate the rod receptors but too dim to stimulate the cone receptors (ex: moonlight and extremely dim indoor lighting) | scotopic |
| an infinite set of different wavelength & intensity combinations can elicit exactly the same response from a single type of photoreceptor | the principle of univariance |
| ______ are sensitive to scotopic light levels? | rods |
| the theory that the color of any light is defined on our visual system by the relationships of 3 numbers (3 #s- the outputs of 3 receptor types now known to be 3 cones) | trichromacy (trichromatic theory of color vision) |
| different mixtures of wavelengths that look identical (more generally, any pair of stimuli that are perceived as identical in spite of physical differences) | metameters |
| a mixture of lights (if light A & light B are both reflected from a surface to the eye, in the perception of color, the effects of those 2 lights add together) | additive color mixing |
| a mixture of pigments (If pigment A & pigment B mix, some of the light shining on the surface will be subtracted by A and some by B- only the remainder contributes to the perception of color) | subtractive color mixing |
| a neuron whose output is based on a difference between sets of cones | cone-opponent cell |
| where are cone-opponent cells? | LGN |
| what are the 3 cone-opponent cells? what colors do they discriminate between? | [L-M] cells & [M-L] cells to discriminate between red and green, [(L+M)-S] cells & [S-(L+M)] cells to discriminate between blue and yellow, [L+M] cells for light onset |
| a 3D space that describes all colors | color space |
| defined by the outputs of long, medium, and short wavelength lights | RGB color space (ie red green blue) |
| defined by hue, saturation, sand brightness | HSB color space |
| what is hue? | the chromatic (color) aspect of light |
| what is saturation? | the chromatic strength of a hue |
| what is brightness? | the distance from black in the color space |
| some colors that we see do not correspond to a single wave length of light (ex: purple & magenta are only perceived when S & L cones are stimulated but M cones are not) | nonspectral colors |
| the theory that perception of color depends on the output of 3 mechanisms (each mechanism based on an opponent between 2 colors: red-green, blue-yellow, black-white) | opponent color theory |
| is there a particular place in the cortex specialized for color processing? | not clear; V1, V2, and V4 are all involved in color perception but not exclusively |
| loss of color vision from brain damage | achromatopsia |
| what happens in step 1 (detection) of color perception? | S, M, and L cones detect light (each cone responds to a different range of wavelengths of light) |
| what happens in step 2 (discrimination) of color perception? | cone opponent mechanisms discriminate wavelengths - [L-M] and [M-L] compute something like red vs green, [(L+M)-S] and [S-(M+L)] compute something like blue vs yellow, [L+M] cells compute something like light onset |
| what happens in step 3 (appearance) of color perception? | further transformation of the signals create fiscal color-opponent appearance |
| single words that describe colors, are used with high frequency and have meanings that are agreed upon by speakers of a language | basic color terms |
| in sensation and perception, the idea that basic perceptual evidence (eg color perception) may be determined in part by cultural environment | cultural relativism |
| a term for what is usually called "color blindness" | color-anomalous |
| what are the 5 types of color blindness? | protanope, deuteranope, tritanope, cone monochromat, and rod monochromat |
| due to absence of L-cones | protanope |
| due to absence of M-cones | deuteranope |
| due to absence of S-cones | tritanope |
| what 2 types of color blindness are red/green color blind? | protanope and deuteranope |
| has only 1 cone type; truly colorblind | cone monochromat |
| has no cones of any type; truly colorblind and very visually impaired in bright light | rod monochromat |
| inability to name objects or colors in spite of the ability to see and recognize them; typically due to brain damage | anomia |
| when 1 stimulus evokes the experience of another stimulus that is not present (ex: letters having colors or sounds having tastes) | synesthesia |
| a color perception effect in which the color of 1 region induces the opponent color in a neighboring region | color contrast |
| the color perception effect in which 2 colors bleed into each other, each taking on some of the chromatic quality of the other | color assimilation |
| a color that can be experienced in isolation | unrelated color |
| a color, such as brown or gray, which is seen only in relation to other colors (a gray patch in darkness appears white) | related color |
| a visual image seen after a stimulus has been removed | afterimage |
| an afterimage whose polarity is the opposite of the original stimulus (light stimuli produce dark negative afterimages; colors are complementary- red produces green afterimage and blue produces yellow afterimages and vise versa) | negative afterimages |
| the tendency of a surface to appear the same color under a fairly wide range of illuminants | color constancy |
| the light that illuminates a surface | illuminant |
| the external world exists | realism |
| the world depends on evidence from the senses; it could be a hallucination | positivists |
| parallel lines remain parallel as they are extended in space | elucidian geometry |
| the increased probability of detecting a stimulus from having 2 or more samples (one of the advantages of have 2 eyes that face forward) | probability summation |
| the combination of signals from each eye in ways that make performant on many tasks better with both eyes than with either eye alone (2 retinal images of a 3D word are not the same) | binocular summation |
| the difference between the 2 retinal images of the same scene | binocular disparity |
| information about the 3rd dimension (depth) of visual spaces | depth cue |
| a depth cue that is available even when the world is viewed with 1 eye alone | monocular depth cue |
| a depth cue that relies on information from both eyes | binocular depth cue |
| a depth que that provides quantitative info about distance in the 3rd dimension | metrical depth cue |
| a depth cue that provides info about the depth order (relative depth) but not depth magnitude | nonmetrical depth cue |
| a cue to relative depth order in which, for ex, 1 object partially obstructs the view of another object | occlusion |
| a depth cue based on the geometric fact that items of the same size form smaller closer spaced images the farther way they get | texture gradient |
| a depth cue based on the implicit understanding that light is scattered by the atmosphere (more light is scattered when we look through more atmosphere thus, more distant objects appear fainter, bluer, and less distinct) | aerial perspective |
| lines that are parallel in the 3D world will appear to converge in a 2D image as they extend into the distance | linear perspective |
| the apparent point at which parallel lines receding in depth converge | vanishing point |
| a comparison os size between items without knowing the absoute size of either one ( all things being equal, we assume that smaller objects are farther away from us than larger objects) | relative size |
| for objects touching the ground, those higher in the visual field appear to be farther away | relative height |
| a cue based on knowledge of the typical size of objects (when you know the typical size of an object, you can guess how far away it is based on how small or large it appears; often works in conjunction with relative size) | familiar size |
| the process by which the eye changes it focus (Lens gets fatter as gaze is directed toward nearer objects ) | accommodation |
| the ability of the eyes to turn inward; often used to focus on nearer objects | convergence |
| the ability of the eyes to turn outward; often used to focus on farther objects | divergence |
| images closer to the observer move faster across the visual field than images farther away | motion paralax |
| points on the retina of each eye where the monocular retina images of a single object are formed are at the same distance from the fovea in each eye | corresponding retinal points |
| the location of objects whose images lie on the corresponding points | horopter |
| the location of objects whose images fall on geometrically corresponding points in the 2 retinas | Vieth-Muller circle |
| region of space, in front of and behind the horopter, within which binocular single vision is possible | Panum's fusional area |
| double vision | diplopia |
| in binocular vision, the problem of figuring out which bit of the image in the left eye should be matched with which bit in the right eye | correspondence problem |
| what are the 3 ways to solve the correspondence problem in binocular vision? | blurring the image (leaving only low spatial freq info helps), uniqueness constraint, (a feature is represented once in each retinal image), continuity constraint (neighboring points lie at similar distances from viewer except at the edges of objs) |
| a way of formalizing the idea that our perception is a combination of the current stimulus and our knowledge about the conditions of the world (this prior knowledge can influence our estimates of the probability of an event) | Bayesian approach |
| the competition between the 2 eyes for control of visual perception | binocular rivalry |
| a measure of the smallest binocular disparity that can generate a sensation of depth | stereoacutiy |
| referring to the presentation of 2 stimuli, 1 to each eye | dichoptic |
| a period of time when the organisms is particularly susceptible to developmental change | critical period |
| a misalignment the 2 eyes such that a single object in space is imaged on the fovea of 1 eye and on a nonfoveal area of the other (turned) eye | strabismus |
| the inhibition of an unwanted image | suppression |
| any of the very large set of selective processes in the brain | attention |
| the form of attention involved when processing is restricted to a subset of the possible stimuli | selective attention |
| attending to a stimuli in the world | external attention |
| attending to 1 line of thought over another or selecting 1 response over another | internal attention |
| directing a sense organ toward a stimulus (ex turning eyes or head) | overt attention |
| attending without giving an outward sign that you are doing so | covert attention |
| splitting attention between 2 different stimuli | divided attention |
| continuously monitoring some stimulus | sustained attention |
| attention is restricted in space and moves from 1 point to the next, area within the spotlight receive extra processing | "spotlight" model |
| attended region can grow or shrink depending on the size of the area to be processed | "zoom lens" model |
| what are the 4 steps in the Poser Cueing Paradigm? | cue, target, task, results |
| what are cues in the Posner cueing paradigm? | can be predictive, nonproductive, or counterpredictive |
| what is the target in the posner cueing paradigm? | neutral trial (target appeared on either location), valid trial (T appeared in indicated location) , invalid trial (T appeared in opposite location) , catch (T didn't appear at all) |
| what is the task in the posner cueing paradigm? | detection task ( target was present/absent) or discrimination task (target appeared to left/right) |
| what are results in the posner cueing paradigm? | reaction time (RT): a measure of the time from the onset of a stimulus to a response |
| the relative difficulty in getting attention (or the eyes) to move back to a recently attn\ended (or fixated) location; | inhibition of return (IOR) |
| the time between the onset of one stimulus and the onset of another | stimulus onset asynchrony (SOA) |
| looking for a target in a display containing distracting elements | visual search |
| what is a target in visual search? | the goal of a visual search / what you are looking for |
| what is a distractor in a visual search? | any stimulus other than the target |
| what is a set size in visual search? | the number of items in a visual search display |
| search for a target defined by a single attribute, such as a salient color or orientation | feature search |
| the vividness of a stimulus relative to its neighbors | salience |
| in visual attention, referring to the processing of multiple stimuli at a time | parallel |
| a search from item to item, ending when a target is found | serial self-terminating search |
| attention is restricted to a subset of possible items based on info about the item's basic features (eg color or shape) | guided search |
| search for a target defined by the presence of 2 or more attributes | conjunction search |
| info in our understanding of scenes that helps us find specific objects in scenes | scene-based guidance |
| the challenge of trying different attributes of visual stimuli, which are handled by different brain circuits, to the appropriate object so we perceive a unified object (eg a vertical red bar moving to the right) | the binding problem |
| hold that a limited set of basic features can be processed in parallel preattentively, but that other properties, including the correct binding of features to objects, require attention | feature integration theory |
| the processing of a stimulus that occurs before selective attention is deployed to that stimulus | preattentive stage |
| an erroneous combination of 2 features of a visual scene (ex seeing a red X when the displays has red letters and Xs but no red X) | illusory conjunction |
| experimental prodecure in which stimuli appear in a stream at 1 location (typically the point of fixation) at a rapid rate ( typically about 8 per sec) | rapid serial visual presentation (RSVP) |
| the difficulty in perceiving and responding to toe 2nd of 2 target stimuli amid a RSVP stream of distracting stimuli | attentional blink |
| what are 3 ways responses of a cell could be changed by attention | response enhancement, sharper tuning, and altered tuning |
| a portion of the visual field with no vision or with abnormal vision, typically resulting from damage to the visual nervous system | visual-field defect |
| in visual attention, the inability to attend to or respond to stimuli in the contralesional visual field | neglect |
| what are the 2 pathways to scene perception? | selective pathway ans noselective pathway |
| permits the recognition of 1 or a very few objects at a time; passes through the bottleneck of attention | selective pathway |
| contributes info about the distribution of features across a scene as well as info about the 'gist" of the scene (does not pass through the bottleneck of attention); computes ensemble statistics | nonselective pathway |
| the average and distribution of properties, such as orientation or color, over a set of objects or a region in a scene | ensemble statistics |
| the description of the structure of a scene (eg enclosed, open, rough, smooth) without reference to the identity of specific objects in the scene | spatial layout |
| the failure to notice a change between 2 scenes | change blindness |
| a failure to notice - or at least to report- a stimulus that would be easily reportable if it were attended | inattention blindness |
| illusion of motion of stationary objects that occurs after prolonged exposure to a moving object; exhibits interocular transfer; occurs in V1 or later because input from both eyes is combined there | motion aftereffect (MAE) |
| the transfer of an effect (such as adaptation) from 1 eye to the other | interocular transfer |
| the illusory impression of smooth motion resulting from the rapid alteration of objects that appear in different locations in rapid succession | apparent motion |
| in the context of motion perception, the problem faced by the motion detection system of knowing which feature in frame 2 corresponds to which feature in frame 1 | correspondence problem |
| an opening that allows only partial view of an object | aperture |
| the fact that when a moving object is viewed through an aperture (or a receptive field), the direction of motion of a local feature or part of an object may be ambiguous | aperture problem |
| the motion of an object that is defined by changes in luminance | first order motion |
| an object that is delineated by differences in reflected light | luminance defined object |
| the motion of an object that is defined by changes in contrast or texture, but not by luminance | second order motion |
| an object that is defined by changes in contrast or texture, but not by luminance | texture defined (contrast defined) object |
| a rare neurophysiological disorder in which the affected individual has no perception of motion; caused by disruptions to cortical area MT | akinetopsia |
| the changing of angular position of points in a perspective image that we experience as we move through the world | optic flow |
| the point in the center of the horizon from which, when we are in motion, all points in the perspective image seem to emanate | focus of expansion (FOE) |
| the pattern of movement of all animals | biological motion |
| moving dots that are correlated (video from class) | Johansson's point-light displays |
| a moving surface can cause stationary objects to "disappear" | motion induced blindness (MIB) |
| what are the types of eye movements? | saccade, smooth pursuit, reflexive, vergence |
| type of eye movement, made both voluntarily and involuntarily, in which the eyes rapidly change fixation from 1 object or location to another | saccade |
| voluntary eye movement in which the eyes move smoothly to follow a moving object | smooth pursuit |
| automatic/involuntary eye movements (eg vestibular eye movements & optokinetic nystagmus) | reflexive |
| a type of eye movement, both voluntary and involuntary, in which the 2 eyes move in opposite directions (convergent->inward, divergent-> outward) | vergence |
| a structure in the midbrain that is important in initiating and guiding eye movements | superior colliculus |
| the reduction of visual sensitivity that occurs when we make saccadic eye movements (eliminates the smear from retinal image motion during an eye movement) | saccadic suppression |
Created by:
abbeysmith20122