J. Gibson (1966)

• Who was concerned about her baby crawling off a cliff?

  Eleanor Gibson
• What did James Gibson assure Eleanor about babies?

  Babies are sensitive to depth cues
• What did Eleanor Gibson test in 1960?

  Theory of depth perception in babies
• What was created for the visual cliff experiment?

  A visual cliff with clear perspex
• What did the mothers encourage their babies to do in the experiment?

  Crawl off the cliff from the other side
• What does the direct or bottom-up theory of perception suggest?

  Perception happens directly and is innate
• Who developed the direct or bottom-up theory of perception?

  James Gibson
• What does Gibson suggest about sensation and perception?

  Sensation is perception
• What depth cues from our natural environment did Gibson consider to provide enough information to accurately perceive the world around us?

  Linear perspective, texture, and color gradient
• What is a key feature of Gibson's theory?

  Perception is inherent at birth
• What does the optic array provide according to Gibson?

  Information to judge depth, distance, and movement
• What is optic flow?

  Everything in our field of vision moving as we move towards or away from a certain
• What does the brain determine from optic flow?

  Speed and direction of movement
• What does it mean if optic flow moves away from a point?

  You are moving towards that point
• What does affordance refer to in Gibson's theory?

  Relationship between object's physical properties and user interaction allows us to directly perceive the meaning or 'use' of an object without the need for past experience
• What does the shape of a door handle afford?

  Pushing or pulling
• What is motion parallax?

  A monocular depth cue that provides cues about difference in distance and motion to help us perceive speed of movement
• How do closer objects appear in motion parallax?

  They appear to move faster
• What happens to a tree far away while driving?

  It appears to move past slowly
• What are the strengths of Gibson's theory in terms of realistic development?

  • Developed using real-world research with pilots in the US Army Airforce where Gibson found that all the information a piolet needed to land a plane was in the total pattern of light that reached the eye
  • Explains how everyday perception of things like move,ent and depth occur
  • Relevant for pilot and design applications
• What is the optic array?

  Our field of vision at any one time
• What are optic flow patterns detected by?

  Our eyes and let our brain know we are moving
• What are some strengths for Gibson's theory in terms of support for the role of nature?

  Research with young infants allows for certain there are no past experiences affecting the experiment

  The visual cliff provides strong support for same reason

  Suggests that infants are born with the ability to perceive depth
• What are some weaknesses of Gibson's theory?

  Unethical research methods-experiment involved young infants who could not express consent themselves

  Theory explains perception solely in terms of environment but there is evidence to show that the brain and experience can influence perception

  Cannot explain visual illusions- direct theory does not explain perceptual errors where the brain draws the wrong conclusions from the environment

  In relation to affordances- what about objects that have less obvious meaning or use?
• What research did Gibson's theory use for realistic development?

  Research with pilots in the US Army Airforce
• What did Gibson find about the information needed to land a plane?

  It is in the total pattern of light
• How does Gibson's theory explain everyday perception?

  It explains movement and depth perception
• In what applications is Gibson's theory relevant?

  Pilot and design applications
• What does research with young infants suggest about perception?

  Infants are born with depth perception
• Why does the visual cliff provide strong support for Gibson's theory?

  It shows infants' innate depth perception
• What is a weakness of Gibson's theory regarding research methods?

  Unethical methods with infants lacking consent
• What does Gibson's theory explain about perception?

  It explains perception solely in terms of environment
• What evidence challenges Gibson's theory about perception?

  Brain and experience can influence perception
• What limitation does Gibson's theory have regarding visual illusions?

  It cannot explain perceptual errors
• What question arises about affordances in Gibson's theory?

  What about objects with less obvious meanings?