General

• perception is how we interpret or make sense of the sensory information we receive
• bottom-up process - perception is based solely on info received by your eyes
• top-down process - here our mind generates expectations of what we look at, help to make sense of information recieved
• information you receive through your senses is known as sensation
• perception is trying to make sense of the information received by senses
• depth cues tells us the depth or distance of an object from the viewer's eye
• monocular depth cues - using one eye to determine the depth or distance between things
• binocular depth cues - depth cues that require the use of both eyes - generally more accurate than monocular
• monocular depth cues:

  • height in plane
  • relative size
  • occlusion
  • linear perspective
• height in plane - hen objects often appear higher up to show their distance - monocular depth cue
• relative size - closer things appear to be larger in an image, further things appear to be smaller - monocular depth cue
• occlusion - involves one object covering the other - the object in front will be closer - monocular depth cue
• linear perspective - straight lines point and converge to one point in the horizon, helps to show distance - monocular depth cue
• binocular depth cues:

  • convergence
  • retinal disparity
• convergence - the eyes focus differently on things closer than they due to further - binocular depth cue
• retinal disparity - compares the 2 images received by each eye, if an object is closer there is a difference from each eye
• motion parallax - the way the visual field changes with movement of close objects seem to move faster than further objects
• visual illusions is when the brain incorrectly interprets depth cues
• illusions:

  • ponzo illusion
  • Muller-Lyer illusion
  • Rubin's vase illusion
  • The necker cube
  • the Kanizsa triangle
  • Ames room illusion
• Ponzo illusion

  
• Muller-Lyer illusion

  
• Rubin's vase illusion

  
• the necker cube

  
• the Kanizsa triangle

  
• ames room illusion

  
• the ponzo illusion relies on the depth cue of linear perspective with the 2 outer lines being drawn differently to create an illusion.

  the line further away feels larger than the one closer to them but they are same distance
• the Muller-Lyer illusion where you see the lines as different lengths dependent on the arrow pointing outwards or inwards but lines are equal length
• ambiguity is where an image leaves an uncertainty as to what it actually is
• the rubins vase is an example of ambiguity - the shape in the middle could be a vase, but the shapes at the side could be 2 faces, and is ambiguous as to which it is
• the necker cube - example of ambiguity - the brain cannot decide on the front face of the cube
• fiction - creating something that isn't there but the brain is left to complete the image
• the kanizsa triangle - example of fiction - you see a triangle in the middle but is not actually there, you 'see' it due to its surrounding shapes
• size constancy - keeping the original information about the size of an object even when it moves or changes
• Ames room - example of size constancy - the room isnt actually a cube of the same size, the back wall and floor get bigger so the person in one corner appears much smaller than the other
• perceptual set - the state of readiness for the information we receive from the environment around us
• all cognitive processes, such as memory, decision making, learning and perception are affected by the perceptual set