U2 ALL

• Sensation


  A physiological and passive process in which raw sensory information is detected by receptor cells in sense organs.
• Perception

  A psychological and active process in which raw sensory information is processed by the brain to assign meaning.
• Top-down processing


  A perceptual process that starts with higher level processing in the brain, working from the whole down to the details.
• Bottom-up processing


  Starts with raw sensory information that is sent to the brain for it to be processed , analysed and interpreted.
• Attention


  The process of focusing on specific stimuli or aspects of the sensory environment whilst ignoring and therefore excluding others.
• Sustained Attention 


  Involves maintenance of attention on a specific stimulus or task for a continuous period of time without being distracted.
• Divided Attention 


  Refers to the ability to distribute our attention so that two or more activities can be done simultaneously.
• Selective Attention


  Involves choosing and attending to a specific visual stimuli whilst at the same time excluding other stimuli.
• Bio factors that influence visual perception

  • Binocular depth cues ( Retinal Disparity and convergence ; two eyes )
  • Monocular depth cues ( Accomadation and pictorial depth cues ; Height in the visual field , relative size, interposition, texture gradient and linear perspective ; one eye).
• Retinal Disparity 


  Refers to a very slight difference in the location of the images on the retina because of the slightly different angles of view, which allows to interpret depth or distance of objects.
• Convergence


  Uses both eyes to focus on same object. As object moves closer , the eyes come closer. As object is further , the eyes move further apart to focus.
• Accomodation


  When the shape of lens is adjusted to focus on an object via bulging and flattening to perceive farther away.
• Height in the visual field 


  Objects closer to the horizon line are perceived as being further away , while objects above or below horizon line are seen as closer.
• Relative size


  When something is smaller we perceive it as further away compared to something larger which is perceived as close.
• Interposition 


  When an object partly covers another , the object that is partly covered by another seems more distant from us.
• Texture Gradient


  When we perceive something with a more detailed pattern as closer to us compared to a less detailed pattern which is perceived as further away.
• Linear Perspective


  Where parallel lines appear to meet in the distance, the closer the parallel lines become the more distant we perceive them.
• Depth perception 


  The ability to accurately estimate the distance of objects and therefore perceive the world in three dimensions.
• Psych factors that influence visual perception

  • Gestalt principles ( Figure ground, closure , proximity and similarity)
  • Perceptual set
• Gestalt principles

  Ways in which we organize the features of a visual stimulus by grouping them to perceive a whole, complete form.
• Figure ground


  Images are divided into a focus and a background
• Closure


  Even if parts of an image are missing , the brain fills in the gaps to perceive a complete picture.
• Proximity


  Objects that are close together as seen as more related.
• Similarity


  Objects that look similar are grouped together.
• Perceptual Set


  A temporary readiness to perceive something in accordance with what we expect it to be.
• Perceptual Set Factors

  • Past experience
  • Memory
  • Context
  • Motivation
• Past experience


  Events or situations that have happened in the past, which can influence how we perceive and respond to new situations.
• Memory


  Ability to store and recall information and experiences.
• Context


  The circumstances or environment in which something happens, which can affect how It is perceived or interpreted.
• Motivation


  Influenced by desires, needs or goals. To see what we want to see
• Visual Illusions 


  Perceptual distortions involving a mismatch between the perceptual experience and physical reality.
• Characteristics of visual illusions

  • Perceptual distortion occurs consistently
  • Perceptual distortion is unaffected by prior knowledge ( that its an illusion)
  • Perceptual distortion is unaffected by prior understanding ( why it occurs)
• Synaesthesia


  A perceptual experience in which stimulation of one sense involuntarily produces the experiences of an additional sense.
• Characteristics of synaesthesia

  • Involuntary and automatic
  • Difficult to suppress
  • Remains consistent over time
  • Unique to each individual
  • Highly vivid
• Causes of synaesthesia

  • Genetic predisposition
  • Enhanced brain connectivity
  • Can develop during early childhood , as a cause of brain still forming connections
• Grapheme-colour synaesthesia


  Perceiving colours when viewing a letter or number.
• Spatial Neglect 


  Loss of awareness of one side of body/space ( visual , auditory, touch, motor)
• Causes of spacial neglect

  • Stroke
  • Head injury
  • Brain tumor
  • Dementia
• Characteristics of spatial neglect

  • only attending to one side of their visual field
  • only aware of sounds coming from one side
  • may not feel sensations from neglected side
  • may not use the limbs on neglected side of body
• Social cognition


  Involves how we perceive, think about and use information to understand and make judgements about ourselves and others in different social situations.