Psychology

1. What is a percept' (1) A percept is the mental representation of actually seeing an object that is perceived through the senses, although the object is seen in two dimension by the proximal stimulus the visual system converts this into a three dimensional percept. 2. What is another name for the retinal image' (1) Another name for retina image is proximal stimulus. 3. This picture is called Leeper’s lady. It is an example of an ambiguous figure. Using the picture as an example, explain what is meant by an ambiguous figure. (2) The term ambiguous figure refers to an image that can be perceived in more than one way. This perception of the image appears to flip between the two alternative images; one interpretation of the image will completely exclude the other image while it persists. In the example of the Leepers Lady you can see either an image of a young lady or an old woman; although both perceptions are there you can only see one of the interpretations at any time, so while viewing the image as the picture of the old women you cannot see the image of the young lady.   4. What do ambiguous figures tell us about visual perception, according to Gregory' (4) According to Richard Gregory ambiguous figures tell us that our visual perceptions can form more than one percept from a single image, which shows us that it requires more than just sensory input to be able to see alternative precepts. When the brain develops two plausible hypotheses for a single image, the image will flip between the two perceptions as the brain is unable to decide them Richard Gregory believed that perception is an active constructive process which relies on top-down processing as well as the visual system receiving input from sensory receptors. When we look at an image we interpret it using cognitive knowledge primary based on prior knowledge and previous experience not just by the image captured by the proximal stimulus, therefore using knowledge and external stimulus and cues we can develop a perceptual hypothesis. 5. Suppose you were going to draw a picture of a landscape or a street scene. Describe three ways in which you could give an impression of depth or distance in the picture. (3) Three ways you can give the impression of depth or distance in a picture is * Linear perspective: Parallel lines that point away from us and gradually get closer together as they recede into the distance, this convergence of line can give the impression of depth in a two dimensional drawing. An example is a path or road where as it goes further away the path/road gets closer together. * Texture gradient: Changing the appearance of the texture of the surface can provide the cue for the perception of a contour and gradual change and therefore giving the impression of distance in a two dimensional picture. An example of this is flowers in a field appearing widely spread in the foreground of a picture and increasingly closer together toward the background of the landscape. * Superimposition: We see an object is further in the distance as it partly hidden by a closer object given the illusion of distance and depth in a two dimensional picture. An example of this is a house being partly covered by a closer house giving the impression that the closer one is being superimposed on the further one. 6. This is the Ponzo illusion. Using the idea of constancy scaling, try to explain how this distortion works. (5)   The Ponzo Illusion is based on our ability to see in three dimensions although the image in seen in two dimension by the retina. It involves appropriate size constancy scaling and linear perspective. In the Ponzo illusion it uses linear perspective with the two converging parallel lines that we interpret those lines as receding into the distance. Size Constancy scaling is the way we tend to perceive objects as remaining the same size despite change in distance, this is an illusion produced by the brain to make objects of relative size to each other. Although the image remains the same size the perception of it can be altered due to the background and retina image is multiplied by the assumed distance making two identical objects look quite different. Now when you put all this together with the Ponzo Illusion it can concluded that the brain judges objects based on its background and with the two parallel lines converging making them appear to be going into the distance and with size constancy scaling making the upper line look larger as it also closer to the parallel lines than the lower line due to the angling of the converging parallel lines. Although both lines are identical in size it appear the lower line is smaller than the upper line.