J.J. and Richard are arguing about how we come to know the world around us. Richard says, “The way we perceive our environment is heavily influenced by our thinking processes, expectations and past experiences.” J.J. replies, “You’re wrong. We perceive our environment directly, by taking in information about shadows, texture, convergence and so on. Expectation and experience play only a minor role.” Who do you agree with more, and why?

We are learning about...We are learning how to... Theories of visual perception. Gibson’s theory of direct perception; Gregory’s constructivist theory of perception. Compare and contrast psychological theories. Construct psychological arguments.

Two experts on perception... J.J. Gibson ( ) believed that we perceive the world directly, and ‘high level’ cognitive processes play a minimal role. Richard Gregory ( ) believed that perception involves constructing a mental model of the world using our beliefs, expectations and experiences.

What is a theory?

Theory A theory is an explanation of some process or phenomenon. It should incorporate and account for what is known about something and should be capable of predicting what will happen under particular circumstances.

Theories of perception A theory of visual perception should be able to explain how we perceive the world. It should also be able to account for the facts we know about visual perception and be able to predict what/how people will perceive under specific conditions.

Gibson’s (1966) theory Perception is a data driven process. We take in information from a constantly changing visual array: – Line & shadow – Texture & texture gradient – Movement (e.g. flow, parallax) Sensory info in the visual array gives affordances (understanding of the nature and possibilities of things in the environment)

Gibson’s (1966) theory What are the affordances of this object?

Gregory’s (1966) theory Perception is a concept driven process We perceive the world by combining incoming sensory information with previously stored information: – Past experiences – Expectations – Knowledge about the world This results in perceptual hypotheses that we modify in the light of updated sensory information

Gregory’s (1966) theory How do we know that this is (a) smooth; (b) plastic; and (c) a chair?

Comparing and contrasting This is a skill based around identifying and explaining the similarities and differences between things. Practising this skill will give you a better understanding of psychological ideas, allowing you to think about them in more complex ways.

Things that are true of Gibson’s theory Things that are true of Gregory’s theory Things that are true of both theories Things that are true of neither theory The Venn diagram method

Homework Compare and contrast Gibson’s and Gregory’s theories of perception (10 marks) – Identify areas of agreement and disagreement – Explain them, referring to what each psychologist said about perceptual processes – Structure your essay around the similarities and differences