Gibson and Walk (KEY RESEARCH)

• What is the study called?

  The Visual Cliff
• What was the aim?

  See if young children and young animals - able to perceive depth innately (and therefore know not to crawl or walk over a visual cliff edge)
• Who were the participants?

  36 children

  6-14 months
• What was the basic procedure

  2 sides to board:

  
  

  -Shallow end, sheet of patterned material placed directly under surface of glass

  -Deep end -> same sheet laid on floor underneath the glass

  
  

  -Each child = placed on board on either side.

  -Childs mum - stand at one end of the box (shallow or deep) + encourage child to crawl towards them
• What did they concluded on the child study?

  Children can perceive depth buy the time they can crawl
• What were some of the animals that they used for the animal part of the study?

  -Chicks

  -Kittens

  -Dark reared kittens

  -Aquatic turtles
• How old were the animals?

  Between less than 24 hours to 27 days
• What were the results from the chicks, goat kids and lambs and kittens?

  Chicks = never crossed deep side - always hopped off on the shallow side

  
  

  Goat kids and lambs = stand on shallow side. When put on deep side = refuse to put legs down or made them go limp

  
  

  Kittens = freeze when placed on deep side or crawl aimlessly in a circle
• What were the results for the dark-reared kittens, rats and aquatic turtles?

  Dark-reared kittens = had no preference for either side - 1 week later avoided the deep side.
• Why did G and W later want to test depth cues?

  Wanted to see which of the two visual cues played in the animals decisive role in depth perception (motion parallax and relative size)
• How did G and W test relative size?

  -Animals could've been judging depth based on size of two sets of squares = deep side (appeared smaller and closer together unlike shallow)

  
  

  -To test if the cue was being used -> Deep side = patterns squares were smaller and closer, shallow side = patterned squares bigger and more spaced.
• What did G and W find after testing relative size?

  -Light-reared young and adult rats - preferred shallow side - large pattern - signified surface being nearer = suggests they used relative size to signify depth

  
  

  -Day-old chicks and dark-reared rats - no significant preference for larger patterns (shallow) - ability to use relative size as depth cue isn't innate in animals (not born with)
• What is motion parallax?

  Nearby objects seen from moving train appear to pass quicker than distant ones
• How did G and W test motion parallax?

  -Larger, more spaced out squares = lowered in depth.

  -Smaller, more close together squares = placed directly under glass surface.

  -Both appear same size, but squares under glass would've moved quicker under their FOV as animals moved head or around board.
• What were G and W finding from the Motion Parallax exp?

  -Day old chicks + dark reared-rats = nearly 100% chose the shallow side - suggests MP was the depth cue they used and that it was innate to them.

  
  

  -Infant rats also chose shallow side nearly 100% time even though deep and shallow side would've appeared the same size on their retinas - shows they also used MP as their depth cue.
• What did G and W conclude about Motion Parallax and Relative Size?

  -It's an innate depth cue

  -Image size is a learned depth cue.