Transcript Powerpoint
DO NOW 1. While ____ involves the stimulation of sense organs, ____ involves the selection, organization, and interpretation of sensory input. a. sensation; perception b. activation; perception c. perception; sensation d. activation; sensation 2. The smallest difference in stimulus intensity that a specific sense can detect is a. a Weber fractional difference b. a detection difference c. a just noticeable difference d. an absolute difference 3. The gradual decline in sensitivity to stimuli that follows prolonged stimulation is a. perceptual adaptation b. sensory adaptation c. sensory overload d. perceptual overload Vision • Our most dominating sense. • Visual Capture What humans see as visible light is a thin slice of the whole spectrum of electromagnetic energy The spectrum of electromagnetic energy Differing Eyes Bee detects reflected ultraviolet wavelengths Phase One: Gathering Light Short wavelength=high frequency (bluish colors, high-pitched sounds) Great amplitude (bright colors, loud sounds) Long wavelength=low frequency (reddish colors, low-pitched sounds) Small amplitude (dull colors, soft sounds) • The light’s wavelength gives us its hue (color). • The height/amplitude of a wave gives us its intensity (brightness). Colors of the Rainbow R O Y G B I V • Color is determined by wave length • Red is the longest wavelength of visible light. Violet is the shortest Unit IV. Sensation and Perception Structure of the Eye Vision Pupil- adjustable opening in the center of the eye, lets light in Iris- a ring of muscle that forms the colored portion of the eye; controls the size of the pupil opening Vision Cornea- layer that protects the eye and bends light to provide focus Lens- transparent structure behind pupil that changes shape through accommodation to focus images on the retina Vision Retina- the light-sensitive inner surface of the eye, containing photoreceptors – rods and cones – and other neurons that begin the processing of visual information Optic nerve- nerve that carries neural impulses from the eye to the brain Vision Blind Spot- point at which the optic nerve leaves the eye, creating a “blind spot” because there are no receptor cells located there Fovea- central point in the retina, around which the eye’s cones cluster Visual Acuity- the sharpness of vision (can be affected by distortions in the eye’s shape) Nearsightedness- condition in which nearby objects are seen more clearly than distant objects because distant objects in front of retina Farsightedness- condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind retina Normal Vision Nearsighted Vision Farsighted Vision How do we correct vision? • Glasses, contact lenses, or LASIK surgery reshape the cornea (which is involved in bending light to provide focus) to correct the problem Light energy Rods and Cones Bipolar Cells Ganglion Cells Retina’s Reaction to LightReceptors Rods peripheral retina detect black, white and gray twilight or low light Cones near center of retina fine detail and color vision daylight or well-lit conditions Light energy striking the rods and cones produces chemical changes that generate neural signals Vision- Receptors Receptors in the Human Eye Cones Rods Number 6 million 120 million Location in retina Center Periphery Sensitivity in dim light Low High Color sensitive? Yes No Pathways from the Eyes to the Visual Cortex Visual Information Processing Feature Detectors nerve cells in the brain that respond to specific features as shape angle movement We have specific cells that see the lines, motion, curves and other features of this turkey. These cells are called feature detectors. DO NOW 1. What is the function of the retina? 2. As people grow older, they are most likely to need glasses because: the iris loses its ability to contract the pupil. the blind spot increases in diameter. the lens loses its ability to change shape readily. the feature detectors progressively decrease in number. the cornea loses much of its transparency. 3. Giulio's bag of marbles is twice as heavy as Jim's. If it takes 5 extra marbles to make Jim's bag feel heavier, it will take 10 extra marbles to make Giulio's bag feel heavier. This best illustrates: a. the opponent-process theory. d. sensory adaptation d. accommodation. e. Weber’s law c. the McGurk effect. Vision • The human eye is much like a camera • Light enters eye & is projected onto a surface Vision Rods & Cones - are Photoreceptors. Rods allows us to see in B/W. sensitive to only light. Cones - color vision. Retina - Takes focused light & image & acts like the film of a camera. It contains photoreceptors which carry the info to the brain via the optic nerve. Pupil - opening in eye • changes shape based on light and emotions. Lens - (Adjusts to the distance of an object by changing its thickness (focuses) Iris – colored portion that controls the size of pupil opening Blind Spot - Spot where optic nerve leaves the eye. - No photoreceptors here. Vision- Receptors Receptors in the Human Eye Cones Rods Number 6 million 120 million Location in retina Center Periphery Sensitivity in dim light Low High Color sensitive? Yes No Vision • Optical Nerve – transmits info from the eye to the brain •Visual acuity - the sharpness of vision Farsighted Nearsighted Normal Vision BURT B. IS YOUR SUPREME COMMANDER Color Vision Two Major Theories Trichromatic Theory Three types of cones: – Red – Blue – Green • These three types of cones can make millions of combinations of colors. • Does not explain afterimages Color-Deficient Vision People who suffer red-green blindness have trouble perceiving the number within the design They lack functioning red- or green- sensitive cones, or sometimes both Opponent-Process Theory The sensory receptors come in pairs. • Red/Green • Yellow/Blue • Black/White • If one color is stimulated, the other is inhibited. Opponent Process- Afterimage Effect