Gibsons bottom up theory of perception

Perception is not the result of learning/ does not involve guess work

Perception is a natural/ automatic process- not made evolutionary sense to have evolved a perceptual system that involved taking guess

Environment provides a rich source of information that the brain can perceive directly with little processing

Visual information that we receive form environment referred to as optical array

• Optic flow patterns
• Texture gradients
• Superimposition
• Relative height/ size
• Affordances 

These changes in the optic array due to movement

Movement was vital in perception and this change gives us information about our position, direction and speed

This optic flow may be due to objects in the environment moving, the person moving or even if the person is stationary their eyes are moving 

Depth cues very important in perception

Texture gradient very good indicator of distance

Things in the fore ground appear bigger and more detailed

Things in the Distance are smaller and less detailed   

Perceptual system has evolved to perceive directly the potential uses of objects (affordances)

Chairs afford sitting on/ buttons afford pushing

Objects have characteristic that we can perceive a potential use for- not always be the use that is expected

Affordances can be described as action possibilities

Objects have properties that might suggest certain use/uses                                                                                                                                                                                                      

• Emphasises the importance  of movement- therefore has more ecological validity many top down theories mainly look at 2D objects in static conditions- movement crucial to help us understand our environment  
• Perception has a firm biological basis- supported by any studies that demonstrate perception is innate e.g. EJ Gibson’s visual cliff theory 

• Dose not explain why visual illusions occur- maintained that they were not important studies with visual illusions lack ecological validity
• The idea of affordances is questionable- dose a chair really afford sitting on- would a person automatically know what to do with it- however as he mentioned before objects do not afford just one use