Flashcards
Unit 3 - Module 18: Sensation: Vision
Cards in this deck (35)
- 1Unit Three - Module 18 Sensation: VisionSensation: Vision
- 2wavelengthA wavelength is the distance between successive peaks in a wave.
- 3frequencyFrequency is the number of complete wavelengths that can pass a point in a given time.
- 4amplitudeThe amplitude of a wavelength is its height.
- 5hueHue is the dimension of colour that we experience - red green blue etc....
The hue is determined by the wavelength of light. The shorter wavelengths gives the purple and blue end of the spectrum. The longer wavelengths give the red end of the spectrum. - 6intensityIntensity is the amount of energy in a light wave, which influences what is perceived as brightness. The intensity is determined by the wave's amplitude.
- 7corneaThe eye's clear, protective outer layer, covering the pupil and iris.
- 8pupilThe adjustable opening in the centre of the eye through which light enters.
- 9irisA ring of muscle tissue that forms the coloured portion of the eye around the pupil and controls the size of the pupil opening.
- 10lensThe transparent structure behind the pupil that changes shape to help focus images on the retina.
- 11retinaThe light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the process of visual information.
- 12fovea centralisA small depression in the retina of the eye where visual acuity is highest. The centre of the field of vision is focused in this region, where retinal cones are particularly concentrated.
- 13optic nerveIt carries sensory nerve impulses from the more than one million ganglion cells of the retina toward the visual centres in the brain.
- 14blind spotA spot where there are no receptor cells because this is where the optic nerve is leaving the eye. However, we don't see a black hole created by this blind spot because our brain automatically fills it in.
- 15accommodationThe process of the lens changing its curvature and thickness in order for the lens to focus the light rays.
- 16myopiaif the lens focusses the image on a point in front of the retina, one sees near objects but not distant objects. This is also known as nearsightedness.
- 17rodsA type of retinal receptor cell that detects black, white, and grey, and is sensitive to movement. They are necessary for peripheral and twilight vision, when cones don't respond.
A human retina has about 120 million rods. - 18conesA type of retinal receptor cell that are concentrated near the centre of the retina and function in daylight or well-lit conditions. They detect fine detail and give rise to colour sensations.
A human retina has about 6 million cones. - 19bipolar cellsBipolar cells are interneurons in the retina that transfer neural impulses from rods and cones to ganglion cells.
- 20ganglion cellsGanglion cells receive neural impulses in the retina from the bipolar cells. The axons of the ganglion cells bundle together to form the optic nerve.
- 21visual acuityThe degree of clarity, or sharpness, of visual perception. It is greatest when the visual image projects directly onto the fovea centralis.
- 22Young-Helmholtz Trichromatic TheoryA theory of how humans perceive colour. According to this theory, the human retina contains three different receptors for colour (meaning each one is most sensitive to one color): one is most sensitive to red, one is most sensitive to green, and one is most sensitive to blue.
These colour receptors combine the colours to produce the perception of virtually any color. You notice that there are no receptors specific to orange, but by stimulating the right cones in the right way, orange color is produced. - 23Thomas YoungA nineteenth century English scientist who contributed to our knowledge of vision. His work led in part to the Young-Helmholtz Trichromatic Theory.
- 24Hermann von HelmholtzA nineteenth century German scientist whose work led in part to the Young-Helmholtz Trichromatic Theory.
- 25colour vision deficiency (colour blindness)Colour vision deficiency is the inability to distinguish certain shades of colour.
- 26afterimageVisual illusions in which retinal impressions persist after the removal of a stimulus.
- 27Opponent-Process TheoryThis theory suggests that the way humans perceive colours is controlled by three opposing systems. We need four unique colours to characterize perception of colour: blue, yellow, red, and green. According to this theory, there are three opposing channels in our vision.
- 28Ewald HeringA German physiologist whose work led to the Opponent-Process Theory of colour vision.
- 29feature detector cellsGroups of nerve cells in the brain's primary visual cortex that respond to specific features of a stimulus, such as colour, form (shape, edges, lines), and movement.
- 30David HubelCanadian neurophysiologist who won a Nobel prize for his co-discovery of feature detector cells in the brain.
- 31Torsten WieselSwedish neurophysiologist who won a Nobel prize for his co-discovery of feature detector cells in the brain.
- 32supercell clustersSupercell clusters are clusters of cells that respond to more complex patterns of visual information.
- 33fusiform face areaLocated in the temporal lobe, it is believed to specialize in face recognition.
- 34parallel processingInformation processing in which two or more sequences of operations are carried out simultaneously by independent processors. A capacity for parallel processing in the human brain would account for people’s apparent ability to carry on different cognitive functions at the same time.
- 35blindsightA condition in which a person can respond to a visual stimulus without consciously experiencing it.
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- Grade 12 Psychology (Unit Three - Sensation and Perception) Flashcards on Unit 3 - Module 18: Sensation: Vision, created by Greg MacPherson on 09/01/2022.
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