perception

• Perception


  The processing, organization and interpretation of the detected information by the brain to make sense of it
• Visual cues


  • Tricks the brain uses to understand from limited information how objects and collections of objects are related to each other in three-dimensional space
• Consistencies


  • The way the brain sees objects as the same despite changes in perspective and size
• Monocular depth cues


  • Cues that can be judged using only one eye, such as height in a plane, relative size, occlusion, and linear perspective
• Binocular depth cues


  • Cues that rely on the fact that we have two eyes, such as convergence of the eyes and binocular disparity
• Size consistency


  The brain's assumption that far away objects are smaller than closer ones, which can lead to misinterpretation of depth cues in visual illusions
• Ambiguity


  When the brain doesn't have enough visual cues to suggest features like depth or distance, leading it to jump back and forth between interpretations
• Fiction


  When the brain perceives something that is not actually detected by the senses, as in the Kanizsa triangle illusion
• Constructivist theory of perception


  Top-down theory suggesting our cognitive processes actively construct our perception using sensory information, stored knowledge, schemas, and expectations
• Direct theory of perception


  Bottom-up theory suggesting we passively and accurately perceive the world directly using information from our senses
• Constructivist theory


  • Sensory information is incomplete, so the brain has to make inferences and guesses to construct a model of reality based on visual cues
  • This model of reality is influenced by factors like experience and culture
• Direct theory


  • Accurate direct perception has evolved in animals to help them navigate the environment
  • We directly perceive the affordances (usefulness) of objects without needing inferences
• Motion parallax


  Provides direct information about features like motion and depth
• The speed of perception is better explained by the direct theory as it requires less mental processing
• The direct theory struggles to explain visual illusions, but the constructivist theory can account for them
• The concept of affordances is rejected by some researchers as many things we use are learned rather than directly perceived
• Perceptual set


  Our brains are thought to be biased in the way they perceive information as sensory information is detected, we focus on some bits of information and ignore all the parts we have a group or a set of expectations based on previous experience that we use to make inferences altering our perception
• Factors influencing perceptual set


  • Culture
  • Motivation
  • Emotion
  • Expectation
• Culture


  Influences the development of people through socialization, we learn norms and values and we tend to share the same mental schemas as other people in our society, this means people with different cultures will perceive the world differently
• Cultural differences in perception


  • Black South Africans were more likely to say the man was hunting the elephant, white Westerners said the antelope
• Motivation


  Can influence perceptual set, if we want an object it will be highlighted in some way in our perception, motivation might be to satisfy basic needs like hunger or thirst or because the object gives us status
• Emotion

  Can influence how we perceive the world and objects in it, for example you might receive someone else's body language as aggressive if you're already in a bad mood or a movie is particularly sad if you're depressed
• Expectation


  Our perception is based on previous experience, so we'll tend to focus on what matches our expectations and then filter out what we're not expected
• Gilchrist and Nezberg study

  1. Assigned participants to either be deprived of food for 20 hours or not

  2. Showed images of food for 15 seconds

  3. Turned off image and showed again with reduced brightness

  4. Participants adjusted image to original brightness

  5. Found food deprived participants adjusted image to be brighter
• Motivation for food


  Changes perceptual set, making food appear brighter to hungry people
• Bruner and Minturn study


  1. Told participants they were recognizing numbers and letters

  2. Flashed a series of numbers or letters onto a screen

  3. Participants wrote down what they saw

  4. Broken B could be interpreted as 13 or B

  5. When primed with numbers, participants more likely to write 13

  6. When primed with letters, participants more likely to write B
• Expectations


  Influence perceptual set, changing how ambiguous stimuli are interpreted