Perception

• What is Perception?

  Perception is how we interpret or make sense of the sensory information that we receive. 
• Sensation


  Information we receive through the senses is known as a sensation.
• Perception

  Perception is all about us trying to understand and make sense of all the information our body receives.
• Sensation


  The process of receiving and detecting sensory input from the environment through our sensory organs such as Eyes, Ears, Nose, tongue and skin
• Perception


  The process of organizing and interpreting sensory information into meaningful patterns and representations
• Sensation


  1. Registering stimuli through sensory receptors

  2. Transmitting information to the brain
• Perception


  1. Attention

  2. Memory

  3. Interpretation
• Sensation involves the basic process of registering stimuli and transmitting them to the brain
• Perception involves higher level cognitive processes that enable us to understand and make sense of sensory information
• There is an area of discussion in psychology as to whether there is a clear-cut difference between sensation and perception
• monocular depth cues

  Cues that help us perceive depth and distance using only one eye
• Monocular depth cues

  • Height in plane
  • Relative size
  • Occlusion
  • Linear perspective
• Height in plane

  Placement of objects in a scene in relation to the horizon or ground. Objects higher in the visual field are perceived as farther away, while those low are perceived as close up.
• Relative size

  Using the size of familiar objects as a reference to determine their distance. Objects that appear smaller are perceived as farther away, while those that appear larger are perceived as closer.
• Occlusion

  Using overlapping objects to determine their relative distance. The covered object is perceived as farther away than the object that is covering it.
• Linear perspective

  The way parallel lines appear to converge in the distance, giving an idea of the distance and depth of a scene.
• Binocular depth cues

  Visual cues that rely on the coordination of both eyes and enable us to perceive depth and distance in three-dimensional space
• Binocular depth cues

  • Retinal disparity
  • Convergence
• Retinal disparity

  The slight difference in the image received by each eye due to their slightly different perspectives. The brain combines these two slightly different images to create a single three-dimensional image. The greater the disparity, the closer the object is perceived to be.
• Convergence

  The inward movement of the eyes when focusing on nearby objects. The brain uses the degree of eye convergence to estimate the distance of an object. When an object is close, the eyes have to converge more, and when an object is far away, the eyes converge less.
• Binocular depth cues allow us to accurately judge distances, sizes, and positions of objects in our environment and play an important role in our everyday visual experiences.
• Gibson's direct theory of perception


  A theory that emphasizes the importance of direct perception which refers to the idea that the human visual system can directly perceive and interpret the sensory information from the environment without requiring any mental interference or processing
• Gibson's direct theory of perception


  • The real world provides sufficient information for our perception and this information is available for direct pickup by the sensory systems
  • Affordances are perceived in a direct and non-inferential manner and the information needed to perceive them is available in the environment itself
• Affordances


  Opportunities for Action that are directly perceivable in the environment
• Motion parallax


  An important cue that plays a role in direct perception, providing information about the relative distance and motion of objects in the environment and this information is available for direct pickup by the visual system
• Motion parallax provides direct and reliable information about the layout of the environment without requiring any mental interference or processing
• Motion parallax


  • When we are moving fast say on a train and the objects closer to us appear to move faster than those further away, the things in the distance are much slower in comparison
• Gibson argued that the information in the environment is invariant, meaning that the information remains the same regardless of the observer's position or orientation
• Visual illusions


  Perceptual phenomena in which our perception of an object or scene does not match its physical reality
• Explanations for visual illusions

  • Ambiguity
  • Misinterpreted depth cues
  • Fiction
  • Size constancy
• Ambiguity


  1. Visual information presented is ambiguous

  2. Can be perceived in two different ways

  3. Leads to perception of object flipping back and forth
• Depth cues


  Visual cues that provide information about the relative distance of objects in the environment
• Misinterpreted depth cues


  1. Depth cues are ambiguous or misleading

  2. Perception of the environment can be distorted
• Fiction


  Brains fill in gaps in the visual information presented
• Size constancy


  Perception of an object's size remains constant even when its distance from us changes
• Visual illusions occur because of complex interactions between our sensory organs, the neural processing of information, and our past experiences and expectations
• Ponzo illusion


  • Two horizontal lines of equal length, top line appears longer due to converging diagonal lines
• Muller-Lyer illusion


  • Two lines of same length, one with outward pointing arrows appears longer
• Rubin vase illusion


  • Image can be perceived as either a vase or two faces in profile
• Ames room illusion


  • Specifically designed room creates optical illusion of depth, making one person appear much larger or smaller