attention & perception

• The purpose of describing sensory receptors, attention and perception is to familiarize you with the way our sense organs collect information and how it is processed by our brain
• Five sense organs


  • Eye
  • Ear
  • Skin
  • Nose
  • Tongue
• Sensation


  The process by which neutral impulses are created by stimulation of sensory neurons that results in awareness of conditions inside or outside the body
• Perception


  The elaboration and interpretation of sensory experiences, governed by our past and present experiences
• Sensation is the process of bringing information into the brain, perception is how we use sensations into meaningful patterns
• Stages of perception


  1. Physical object (distal stimulus)

  2. Optical image on retina (proximal stimulus)

  3. Determine distal stimulus from proximal stimulus
• Perception


  • Involves physical properties such as shape or size and past experiences
• Laws of perceptual grouping


  • Proximity
  • Similarity
  • Continuity
  • Closure
  • Common region
• Perceptual constancy


  Perception of an object's shape, size or brightness remains the same even though its image on the retina has changed

  
• Size constancy


  Perceived size of an object remains the same, even though the size of its image on the retina changes
• Shape constancy


  The shape of an object remains stable even though the shape of its retina image changes
• Perceptual organization


  Determinants of how we organize sensory information into meaningful patterns
• Perceptual organization


  • Figure-ground organization
  • Perceptual constancy
  • Depth perception
• Figure-ground organization


  The tendency to perceive objects as distinct from their background
• Figure-ground organization


  • Seeing dots in a circular fashion as a complete circle
• Closure


  The tendency to complete a figure that is incomplete but has a consistent overall form
• Common region


  Stimuli that are found within a common area tend to be seen as a group
• Fig. 5.3 shows the Laws of Perceptual Grouping
• Size constancy


  The perceived size of an object remains the same, even though the size of its image on the retina changes
• Brightness constancy


  The brightness of objects appears to stay the same as lighting conditions change
• Depth perception


  The ability to see three-dimensional space and to accurately judge distances
• Depth perception


  • Partly innate and partly learned
  • Requires monocular and binocular cues
• Monocular cues


  Depth cues that work with just one eye
• Binocular cues


  Depth cues that require two eyes, the most basic source being retinal disparity
• Pictorial cues


  Features found in paintings, drawings and photographs that impart information about space, depth and distance
• Pictorial cues


  • Railway tracks appearing to meet at the horizon
• Illusion


  Distorted perception of stimuli that exist
• Illusions


  • Muller-Lyer illusion
  • Ponzo illusion
  • Horizontal-vertical illusion
• Hallucination


  Perception of objects or events that have no external reality
• Eyewitness testimony is key to decisions in the judiciary, but psychologists believe eyewitness errors are very common</b>
• Perceptual awareness


  Some people perceive things more accurately than others
• Habituation


  Stopping paying attention to familiar stimuli
• Creative people attend to stimuli, even those that are repeated
• Perceptual clarity requires rigorous effort of paying more and more attention
• Breaking perceptual habits and interrupting habituation can lead to good results
• Questioning your own perceptions by bringing another interpretation can lead to marvelous outcomes