perception

• Sensation


  Fundamental raw experiences associated with a stimuli
• Perception


  Integration and meaningful interpretation of those raw sensory experiences
• Levels of Sensation vs Perception

  • Psychological
  • Biological
• Sensory Processes


  • Involve the sense organs and the neural pathways that emanates from them which are concerned with the initial stages of acquiring stimulus information
• Perceptual Processes


  • Involve higher levels of the cortex, which are more related to meaning
• Attention


  The process by which we select some stimuli for further processing while ignoring others
• Eye Movements


  • Fixations - brief periods during which the eyes are relatively stationary
  • Saccades - quick jumps of the eye from one place to the next
• Unusual object in a scene


  More eye fixations directed to it compared to normal objects
• Weapon Focus


  Rapt attention on a weapon in a scene
• We can selectively attend to some visual stimulus without moving our eyes
• Attention is multi-modal. It can move within a modality or between modalities
• We are consciously unaware of and remember little, if anything about unattended information
• Shadowing


  Repeating back one auditory message
• Localization


  Determining an object's position in the up-down and left-right dimensions
• Figure


  Contains the object of interest, which appears more solid than the ground and appears in front of it
• Ground


  Region that appears to be behind the figure
• Gestalt


  German word meaning "form" or "configuration"
• Gestalt Laws of Organization

  • Similarity
  • Proximity
  • Closure
  • Good Continuation
  • Common Movement
• Depth Cues


  Different kinds of visual information that provide information about an object's depth
• Binocular Cues


  • Binocular Disparity - difference in the views seen by each eye
• Monocular Cues


  • Relative Size
  • Interposition
  • Relative Height
  • Perspective
  • Shading and Shadows
  • Relative Motion
• Stroboscopic Motion


  Produced by flashing a light in darkness and then flashing another light near the location of the first light
• Real Motion


  Movement of an object through all intermediate parts in space
• Agnosia


  Breakdown or disorder in recognition who have suffered from certain kinds of brain damage
• Associative Agnosia


  Patients with damage to temporal lobe region of the cortex have difficulty recognizing objects only when they are presented visually
• Prosopagnosia


  Unable to recognize familiar faces as a result of damage to a particular region on the right side of the brain
• Abstraction


  The process of reducing the vast amount of information that comes in from the physical world through our senses to a more manageable set of categories
• Perceptual Constancies


  The brain's ability to maintain a perception of the underlying physical characteristics of an object such as shape, size, or color even when the sensory manifestations of the these objects change critically
• Color Constancy


  Ability of the visual system to perceive the reflectance characteristics - an inherent property of the object no matter what the source wavelength
• Brightness Constancy


  The perceived lightness of a particular object changes very little, if at all, even when the intensity of the source changes drastically
• Shape Constancy


  The perceived shape is constant while the retinal image change
• Size Constancy


  An object's perceived size remains relatively constant no matter how far away it is
• Illusions


  A perception of something that differs systematically from physical reality
• Cross Modal Illusions


  Illusions that occur because of conflicting information
• McGurk Effect


  Results from conflicting auditory and visual information, producing a perception of "da-da"