What are illusions?

a visual illusion is a conflict between reality and what we perceive
fiction illusions are caused when a figure is perceived even though it is not present in the stimulus
1. these often involve an illusory contour - a boundary that is perceived in a figure that is not present in the stimulus
after-effects are like fictions in the way that they involve perceiving something like movement or a shape that is not in the stimulus, this happens when we look at a stimulus for a long time and then look away
1. a motion after-effect is an illusion caused by paying attention to movement in one direction and perceiving movement in the opposite direction immediately afterwards
2. a colour after-effect is an illusion caused by focusing on a coloured stimulus and perceiving opposite colours immediately afterwards
3. the retina has red, blue and green cones, red and green cones tell us about yellow, these works in pairs, red and green, blue and yellow
  1. looking at something red for a long time means the cells that detect red will get tired and the green cells will be more active
ambiguous figures are stimuli with 2 possible interpretations, in which it is possible to perceive only one of the alternatives at any time
1. eg. Leeper's Lady and the Necker Cube
distortion illusions are where our perception is deceived by some aspect of the stimulus, this can affect the shape or size of an object
1. eg. the Ponzo iIlusion, the Muller-Lyer illusion, the Herring illusion and the Ebbinghaus illusion

Resource summary

	Created by sophieisnotakise about 10 years ago