Different Visual Illustrations in Perception

Different Visual Illustrations in Perception How can visual illusions illustrate top down processes in perception?

Contrast this with a visual illusion that can be explained through

bottom up processes.

Text Box:

Figure 1 Muller Lyer illusion

There are many

suggestions to explain how visual illusions can be perceived. These

suggestions include physical illusions, bottom up illusions and top

down illusions. An example of a physical illusion is how a straight

stick when placed in water appears bent. Here the illusion has

occurred before the light has entered the eye and so is a physical

illusion. Bottom up and top down illusions however involve the

processing after the light has entered the eye. Bottom up processes

are processes which take information into the eye and then make

judgements about the nature of the visual world based solely on this

information. Hering who suggested that it was the innate ability of

the visual system that led to how things were perceived illustrates

this. Top down processing however involves using prior knowledge and

experience about the structure of the world to influence how something

is perceived. Helmholtz who felt that the perception of a stimulus

was based on visual experience illustrated this. The following

illusions show examples of how both processes can be used to explain

perceptions.

Text Box:

Figure 2 shows how the Muller ...

... middle of paper ...

... bottom up and top down processes combined to

perceive an illusion. And so as it is hard to provide an adequate and

clear-cut explanation for an illusion and these explanations remain

different for each illusion, the perception of illusion becomes

subjective.

References

S Coren, L M Ward & J T Enns 2004 Sensation and Perception 6th edn

W N Dember & J S Warm 1979 Psychology of Perception 2nd edn

Purves & Andrews 1997 The Perception of Transparent Three Dimensional

Objects Proc. Natl. Acad. Sci. USA Vol 94

Mach Bands 1965 Quantitative Studies on Neural Networks in the Retina

Holden Day

M W Eysenck 2004 Principles of Cognitive Psychology 2nd edn Psychology

Press

Bruner, J. S., Postman, L., & Rodrigues, J. (1951). Expectations and

the Perception of Colour. American Journal of Psychology, Vol 64