Visual illusions

• What is size constancy in visual perception?

  The brain perceives objects as constant size
• How does the brain handle familiar objects at different distances?

  It perceives them as a constant size
• What happens when objects in the distance appear smaller?

  They are scaled up by the brain to normal size
• What can create a visual illusion regarding distance?

  The brain perceives distance when there isn’t any
• What does the Ponzo illusion illustrate?

  Converging lines create an illusion of distance
• How does the brain interpret the lines in the Ponzo illusion?

  It scales up the distant line and down the closer line
• What is the Müller–Lyer illusion based on?

  Shapes of fins resembling building corners
• How do ingoing and outgoing fins affect perception in the Müller–Lyer illusion?

  Ingoing fins suggest distance, outgoing fins suggest nearness
• What does the brain do with the line that appears closer in the Müller–Lyer illusion?

  It mentally scales it up to appear longer
• What are ambiguous figures in visual perception?

  Images with two possible interpretations
• What happens when the brain encounters ambiguous figures?

  It cannot decide which interpretation to choose
• How can the Necker cube be perceived?

  As pointing upwards or downwards
• What is fiction in the context of visual illusions?

  Perception of something that is not there
• What does the Kanizsa triangle illustrate?

  Illusory contours creating an overlapping triangle
• How does the Kanizsa triangle create its effect?

  By using illusory contours