Lecture notes- Cognitive Psychology: Vision for action

L10- Vision for action

Why do we see?




Information in ‘active vision’
 Spatial structure of scenes
- Orientation + layout of objects + surfaces

 Motion
- Direction + speed of moving objects (obstacles)
- Optic flow

 Depth
- Distance information

 Affordances
- Action-inducing objects properties

Affordances




 Properties of the environment
- Surfaces of object in scenes

 Potential functional relations
- For acting upon- for behaviour

 Surfaces as the essence of our environment

Gibson (1986) on affordance
 It implies the complementarity of the animal + the environment

 “The affordances of the environment are what it offers the animal, what it provides or
furnishes- either for good or ill”

, Redefining the study of vision
 How is vision possible?
- Mechanics of processing visual input
- Psychophysics, computational theories
- Interfacing with memory e.g. recognition

 How does vision guide our behaviour?
- Actions in scenes + towards objects
- Selection of objects for action




Neuropsychological evidence
 Hypothesis- selective damage to dorsal/ventral stream should generate deficits specific
to that stream’s function

 Patients with visual cortical damage show selective deficits that match the
dorsal/ventral interpretation

Ventral stream deficits
 Category-specific deficits
- Naming living vs non-living objects
- Often temporal lobe deficit i.e. ventral stream

 Visual object agnosia
- Problems recognising objects/forms