PSYC 230 Module 7 Study Guide PDF

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Module 7 study guide and answers...

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Important concepts to know – Module 7 The concepts listed below are the most important ones for you to understand in this module. You can use this list to help you with notetaking while you watch the videos.

Unit 11 – Color Perception § Wavelengths of Light and Color o Heterochromatic light: white light, consisting of many wavelengths o Monochromatic light: light consisting of one wavelength o Spectral reflectance: the ratio of light reflected by an object at each wavelength § Achromatic Lightness § Hue: the color quality of light, corresponding to the color names we use, such as orange, green, indigo, and cyan; hue is the quality of color § Saturation: the purity of light § Lightness: the psychological experience of the amount of light that gets reflected by a surface § Brightness: the perceived intensity of the light present § Additive color mixing: the creation of a new color by a process that adds one set of wavelengths to another set of wavelengths § Subtractive color mixing: color mixing in which a new color is made by the removal of wavelengths from a light with a broad spectrum of wavelengths § Metamer: a psychophysical color match between two patches of light that have different sets of wavelengths § Color-Matching Experiments § The Retina and Color o S-cone: the cone with its peak sensitivity to short wavelength light, around 420 nm (blue) o M-cone: the cone with its peak sensitivity to medium wavelength light, around 535 nm (green) o L-cone: the cone with its peak sensitivity to long wavelength light, around 565 nm (yellow) o The response of cones to a 500-nm light § Univariance: the principle whereby any single cone system is color blind, In the sense that different combinations of wavelength and intensity can result in the same response from the cone system o Why More Than One Receptor is Necessary to See in Color? § The Trichromatic Theory of Color Vision: the theory that the color of any light is determined by the output of the three cone systems in our retinae o Three cone systems in our retinae § The Opponent Theory of Color Perception o Hering’s model of opponent processes § Findings That Support Opponent Theory o Perception of color combinations o (Spontaneous) sorting into four groups, across all cultures o Afterimages: visual images that are seen after an actual visual stimulus has been removed o Simultaneous color contrast: a phenomenon that occurs when our perception of one color is affected by a color that surrounds it § Opponent Cells in the LGN and V1 o Cone-opponent cells in LGN: neurons that are excited by the input from one cone type in the center but inhibited by the input from another cone type in the surround o Color-opponent cells in V1: neurons that are excited by one color in the center and inhibited by another color in the surround, or neurons that are inhibited by one color in the center and excited by another color in the surround

o Double-opponent cells: cells that have a center, which is excited by one color and inhibited by the other; in the surround, the pattern is reversed § Color Processing in the Brain § Why are our veins GREEN? § Color Deficiency: the condition of individuals who are missing one or more of their cone systems o Rod Monochromacy: a rare form of color deficiency, have no functioning cones of any kind and therefore can be described as truly colorblind. See the world in shades of gray, high reflectance objects are white, low reflectance objects are black, and intermediate reflectance objects are various shades of gray o Cone Monochromacy: lack two cone types but have one present. Have poor acuity and high sensitivity to bright light. World appears in blacks, whites, and grays. o Dichromacy: only have two working cone systems, they can see colors, though a much lesser range of colors than do trichromats § A Description of Different Types of Color Vision o Tritanopia: a lack of S-cones, leading to blue-yellow color deficiency; this trait is rare and not sex linked o Protanopia: a lack of L-cones, leading to red-green deficiency, this trait is sex-linked and this more common in men o Deuteranopia: a lack of M-cones, leading to red-green deficiency; this trait is rare and not sex linked § Cortical Achromatopsia: loss of color vision due to damage to the occipital lobe § Color Demo § Light source: monochromatic light source, yellow light. § Under these conditions, only the yellow-blue opponent channel can help us do color discriminations. You will experience the world as a color deficient individual does. § Let’s examine the errors we made: § Brown-blue: look alike § Red-green: difficult to tell them apart § Yellow-orange: look alike § Yellow surfaces: this color is reflected and coded along the yellow-blue channel. § Red and green surfaces: these surfaces reflect a little bit of yellow light, however red and green cannot be coded by the yellow channel. § Why? § Blue surfaces: blue is the opponent color of yellow. So, the yellow light will remove or “kill” the blue (go back to the Hue Cancellation experiments). Blue surfaces reflect only very little light, so they will look very dark. § Brown surfaces: these surfaces don’t reflect a lot of light in general, so they will look dark. § Orange surfaces: what is orange? Yellow + red. Yellow is reflected but red is not and cannot be coded by the yellow channel. § What is constancy? The ability to perceive an object as the same under different conditions § What is color constancy? The ability to perceive the color of an object despite changes in the amount and nature of illumination § What is lightness constancy? The ability to perceive the relative reflectance of objects despite changes in illumination § Color-Based Acuity § Does Everyone See Colors the Same Way? o Cultural Relativism § Eleanor Rosh vs. Debi Roberson § Synesthesia

o Watercolor illusion in synesthesia

Unit 12 – Movement and Action § Which parts of the fovea are seeing the motion? How Slow and How Fast? § Real motion: motion in the world created by continual change in the position of an object relative to some frame of reference § Apparent motion: the appearance of real motion from a sequence of still images § The correspondence problem: how the visual system knows if an object seen at time 1 is the same object at time 2 § How does the visual system correctly perceive the overall motion of objects? § Induced motion: an illusion whereby one moving object may cause another object to look as if it is moving § The Neuroscience of Vision and Motion § Motion Detection in the Retina § Reichardt detectors: neural circuits that enable the determination of direction and speed of motion by delaying input form one receptive field, to determine speed, to match the input of another receptive field, to determine direction § Corollary Discharge Theory: the theory that the feedback we get from out eye muscles as our eyes track an object is important to the perception of motion § Eye Movements o Saccades: most common eye movements, are used to look from one object to another, saccades are very rapid o Smooth-pursuit eye movements: the voluntary eye movements we use to track moving objects, can only do these when there is an actual moving object in the environment § MT: The Movement Area of the Brain o Akinetopsia (motion blindness): a rare condition in which an individual is unable to detect motion despite intact visual perception of stationary stimuli, caused by damage to area MT o Stimuli used in Newsome and Paré’s (1988) experiment o Weigelt et al.’s (2013) results o fMRI results from Kaas et al. (2010) § Motion Aftereffects: a motion based visual illusion in which a stationary object is seen as moving in the opposite direction of real or apparent motion just observed § Form Perception and Biological Motion § How do we interpret point-light walker display? § What is the concept of Affordance? Information in the visual world that specifies how that information can be used § Optic flow § Gradient of flow: the difference in the perception of the speeds of objects moving past us in an optic flow display § Focus of expansion: the destination points in an optic flow display, from which point perceived motion derives § Visually Guided Eye Movements o Lateral intraparietal (LIP) area: an area of the primate parietal cortex involved in the control of eye movements § Visually Guided Eye Movements o An experiment showing the function of the LIP region of the parietal lobe. § Visually Guided Grasping

o Medial intraparietal (MIP) area: an area of the posterior parietal love involved in the planning and control of reaching movements of the arms o Anterior intraparietal (AIP) area: a region of the posterior parietal love involved In the act of grasping...