DP3

• biological factors - physical, physiological, neurological, genetic conditions that affect an individual
• biological factors are entirely internal, and they influence physiological functioning and the way we perceive the world around us
• depth perception - the ability to see three-dimensional space and to accurately judge distances using environmental cues
• to accurately perceive depth, our visual system needs to be intact.

  • eyes retinas
  • optic nerves
  • brain
• depth perception relies on depth cues - variety of internal and external stimuli that inform the visual system about the depth of an object/ distance from observer
• depth cues:

  • binocular - two eyes
  • monocular - one eye
• binocular cues

  • two eyes
  • provide brain with information about depth/ distance
  • retinal disparity
  • convergence
• retinal disparity is a depth cue created by the small differences between the image that reaches the right eye and the image that reaches the left eye
• convergence involves both eyes simultaneously turning inwards as an object moves closer (within 7 metres) in order to maintain focus on the object
• monocular cues:

  • depth perception cues that rely on information from only one eye
  • accomodation
  • pictorial cues
• accomodation involes the muscles attached to the lens in each eye in/voluntarily relaxing/contracting to alter the shape of each lens in eachbeye so it can focus on objects at varying distances
• pictorial cues are monocular cues present in two-dimensional images that allow the brain to perceive apparent three-dimensional depth
• pictorial cues

  • linear perspective
  • relative size
  • interposition
  • texture gradient
  • height in the visual field
• pictorial cues: linear perspective - the apparent convergence of parallel lines creates the impression of increasing distance
• pictorial cues: relative size - the smaller retinal image of two objects is perceived as further away, and the larger retinal image of the two objects is perceived as being closer
• pictorial cues: interposition - when one object partially blocks another object, its perceived as being infront of and closer than the object it covers
• pictorial cues: texture gradient - the surface features of an object are percevied smaller and less detailed the more distance on object becomes
• pictorial cues: height in the visual field

  • objects close to the horizon line appear further away
  • objects below the horizon line placed higher in a picture appear more distance than objects placed further below the horizon line
  • objects above the horizon line placed lower in a picture appear more distant than objects below, but close to, the horizon line
• psychological factors - processes that operate at the individual level that impact the mental state and cognition of an individual and therefore influencing their behaviours
• psychological factors

  • gestalt principles
  • context
  • motivation
  • past experience
  • memory
• visual perception principles - rules our brains apply automatically to organise and interpret visual stimuli in a consistent and meaningful way.

  • gestalt principles
  • visual constancies
• gestalt principles - when we organise seperate stimuli into meaningful patterns so we have some order to our perceptions

  • figure ground
  • closure
  • similarity
  • proxomity
• gestalt principle: figure-ground - figure is what stands out from its background (foreground)
• gestalt principle: similarity - grouping together things that look similar
• gestalt principle: proximity - objects close together are perceived as being related or part of one thing
• gestalt principle: closure - perceptually completeing an incomplete figure by filling in an imageinary contour line so that the figure has a consistent overall form
• visual constancies - the group of perception principles that allow us to view objects as unchanging in terms of their

  • size
  • shape
  • brightness
  • orientation
  • even when there are changes to the image that the object casts on the retina
• visual constancy: size - even though images get smaller as they move away, we still see them as having the same size
• visual constancy: shape - even if the outline of an object becomes distorted, we can still recognise it
• visual constancy: brightness - even if light levels change, we still see objects as having the same level of brightness
• visual constancy: orientation - even if an object appears tilted, it's still seen as upright
• psychological factors influencing visual perception

  • context
  • motivation
  • past experience
  • memory
• context - how our perceptions may be influenced by what is around us at the time
• motivation - how our perceptions may be influenced by whether or not we want something to happen
• past experience - prior exposure to stimuli creating an internal expectation to intepret similar stimuli in the same way we have already before
• memory - how past experiences can influence current perceptions
• social factors - aspects of interactions with other people, groups, society and culture that influence how we think and behave
• culture involes all the distinctive beleifs that provide context for social behaviours that are handed down from one generation to the next, influncing the how we perceive the environment around us
• culture creates differences in contexts and experiences that individuals draw from when perceiving new information
• some cultures view stimuli more holistically

  westerners - focus on central object

  South Africans - two dimensional