psych aoss2

• Sensation


  The process by which our sensory receptors and sense organs detect and respond to sensory information that stimulates them
• Perception


  The process by which we give meaning to sensory information
• Stages of sensation and perception

  1. Reception

  2. Receptive fields

  3. Transduction

  4. Transmission

  5. Interpretation
• Reception


  The process of detecting and responding to incoming sensory information
• Receptive fields


  The area of space in which a receptor can respond to a stimulus
• Transduction


  The process by which the receptors change the energy of the detected sensory information into a form which can travel along neural pathways to the brain as action potentials
• Transmission


  The process of sending the sensory information (as action potentials) to relevant areas of the brain via the thalamus
• Interpretation


  The process in which incoming sensory information is given meaning so that it can be understood
• Visual sensory system


  • All the parts of the eyes
  • The neural pathways that connect the eyes and the brain
  • The areas of the brain that process visual information
• Pupil


  Dilates to allow more light into the eye when there is low light, and contracts to restrict the amount of light entering the eye when there is bright light
• Iris


  The coloured part of the eye, a ring of muscles that expand or contract to change the size of the pupil and control the amount of light entering the eye
• Lens


  A transparent, flexible, convex structure located immediately behind the pupil that focuses light onto the retina
• Vitreous humour


  A jelly-like substance that helps to maintain the shape of the eyeball and also helps focus light
• Retina


  Receives and absorbs light and also processes images, consisting of several layers of nerve tissue made up of different types of neurons including light-sensitive visual receptor cells called photoreceptors
• Rods


  Photoreceptors that respond to very low levels of light and are primarily responsible for night vision, but are poor at detecting fine details and colour
• Cones


  Photoreceptors that respond to high levels of light, are primarily responsible for vision in bright conditions, and detect fine detail and colour
• From the retina to the brain

  Photoreceptors convert light into signals processed by neurons in the retina, which then generate action potentials transmitted to the brain via the optic nerve
• Optic nerve


  Carries the visual information from the retina to the primary visual cortex
• Blind spot


  The area of the retina where the optic nerve exits, with no photoreceptors so light cannot be detected there
• Optic chiasm


  The point where the axons from the left and right sides of the retinas cross over, transmitting visual information to the opposite sides of the brain
• Light


  Visible light is a part of the electromagnetic energy spectrum, with wavelength determining colour and amplitude determining intensity
• Visible light spectrum


  The narrow range of electromagnetic waves that photoreceptors in the human eye are sensitive to
• Distal stimulus


  Stimuli outside the body
• Proximal stimulus


  The energies that reach the sensory receptors
• Gestalt principles of visual perception

  • Figure-ground organisation
  • Closure
  • Similarity
  • Proximity
• Figure-ground organisation


  Part is viewed as a defined figure, the rest becomes the ground that surrounds the figure
• Closure


  Tendency to mentally 'close up', fill in or ignore gaps to perceive objects as complete
• Similarity


  Tendency to perceive stimuli or parts of a stimulus that have similar features as belonging together
• Proximity


  Tendency to perceive parts of a visual stimulus that are positioned close together as belonging together in a group
• Depth perception


  The ability to accurately estimate the distance of objects
• Depth cues


  • Binocular depth cues
  • Monocular depth cues
• Binocular depth cues


  Require the use of both eyes to provide information about depth and distance, including convergence and retinal disparity
• Convergence


  The brain detecting and interpreting depth or distance from changes in tension in the eye muscles as they turn inwards to focus on close objects
• Retinal disparity


  The slight difference in the location of visual images on the retinas, enabling judgments about depth and distance
• Monocular depth cues


  Provide information about depth and distance using only one eye, including accommodation and pictorial cues
• Accommodation


  The automatic adjustment of the shape of the lens to focus an object in response to changes in distance
• Pictorial depth cues


  • Linear perspective
  • Interposition
  • Texture gradient
  • Relative size
  • Height in the visual field
• Linear perspective


  The apparent convergence of parallel lines as they recede into the distance
• Interposition


  When one object partially blocks or covers another, the partially blocked object is perceived as further away
• Texture gradient


  The gradual reduction of detail in a surface as it recedes into the distance