Gregory (1970) and Top Down Processing Theory
Psychologist Richard Gregory (1970) argued that perception is a constructive process which relies on top-down processing.
Stimulus information from our environment is frequently ambiguous so to interpret it, we require higher cognitive information either from past experiences or stored knowledge in order to makes inferences about what we perceive. Helmholtz called it the ‘likelihood principle’.
For Gregory perception is a hypothesis, which is based on prior knowledge. In this way we are actively constructing our perception of reality based on our environment and stored information.
A lot of information reaches the eye, but much is lost by the time it reaches the brain (Gregory estimates about 90% is lost).
Therefore, the brain has to guess what a person sees based on past experiences. We actively construct our perception of reality.
Richard Gregory proposed that perception involves a lot of hypothesis testing to make sense of the information presented to the sense organs.
Our perceptions of the world are hypotheses based on past experiences and stored information.
Sensory receptors receive information from the environment, which is then combined with previously stored information about the world which we have built up as a result of experience.
The formation of incorrect hypotheses will lead to errors of perception (e.g. visual illusions like the Necker cube).