•Our visual world is constantly changing as we move yet we perceive our environment as stable. •The image on our retina is constantly changing yet we don’t think objects are growing, changing shape or colour as we move, or our eyes move •visual constancies – the tendency for objects to provide the same visual experience despite changes in the viewing conditions.
•The perception that an object remains the same size even though the image on our retina changes as it moves. •Even though an object or person appears smaller as it moves away, we know it is not shrinking.
Gregory’s constructionist theory:
experience tells us people don’t shrink or grow so we infer they are coming closer or moving away.
Gibson’s direct theory:
we use the cue of relative size, we judge things within the context of their surroundings. All information for size constancy is located within the stimulus
The ability to perceive objects as having a stable shape even if their orientation changes (they change direction or angle)
Gregory's and Gibson’s explanations
•Constructivist view: Our experience of seeing doors open in the past. •Direct perception: there is enough information in the background and texture of the door to know it is still the same object. •But ..... The bottom up approach has difficulty explaining visual errors.
•Understanding things stay the same colour in different levels of light.