Question

-       The difference between sensation and perception. The difference between bottom-up and top-down processing, this is as important as it can get. Examples of top-down processing related factors such as visual context, expectations effects, regularities in the environment, and the Gestalt rules of perceptual grouping. Examples of depth cues must be familiar and they could be discussed in relation to bottom-up and top-down processing. The role of top-down processing in the hollow-face illusion and the Ames room illusion is important.

Answer 1

Sensation is the impression by by sense organs. As for example, the scent of a flower, the appearance of a bird etc. On the other hand, perception is the comprehension of sensory stimuli. With perception we can differentiate various types of stimuli. We can distinguish red flower from white flower for perception.

In the bottom-up processing the process starts from the sensory levels and goes to the brain. The process from sensory level to brain is called bottom-up process. On the other hand, top-down process refers to the process from brain to the sensory organs. After bottom-up process, There is processing and then top-down processing starts. When we see a snake our visual senses receive the stimuli and it is called bottom-up process. Then we are frightened and ne cautious. It is called top-down process.

Gestalt rules of perception says that human eyes detect visual object on the basis of shape. It is said the human eyes make simplification of complex shape with some patterns. These patterns are universal and the shape is recognized with similarities. The shape of various points can be lined in different ways and the patterns are detected by the depth perception of visual sensation. On the other hand, a simple shape can be recognized with many complex shapes. This is called proximity. With the rules of continuation the points are recognized with many points. With continuation there is an autonomous effort of the visual sense to complete the shape.