perception deveploment

• Perception


  The process by which our minds organise, process and make sense of sensory data
• Sensation


  The actual 'seeing' of what is in the visual field, a passive biological process
• Perception


  An active cognitive process where we construct a picture, not just passively receive it

  
• Illusion


  Figures which appear to be other than they really are
• Visual illusions


  • The horizontal lines appear different lengths
  • The vertical lines appear different lengths
  • The red dot appears on the near or far corner
  • The cube appears to 'jump' (depth reversal)
• Visual illusions are examples of the visual system 'breaking down' and the brain perceiving information differently
• You are not actually 'seeing' the words, you are perceiving them - your brain is making the best possible interpretation

  
• Types of perceptual development in children


  • Pattern perception
  • Face perception
  • Constancies
  • Depth perception
• Pattern perception in infants


  • Prefer complex patterns compared to simple patterns
  • Prefer patterns that resemble a human face
• Face perception in infants


  • Discriminate their mother's face from other female faces
  • Prefer attractive faces over unattractive faces
  • Prefer faces of their own ethnicity
• Face perception development


  1. 1 month - Recognise mother's face frontally but not in profile

  2. 5 months - Differentiate between smiles of different intensity and fear

  3. 7 months - Less likely to prefer upside down faces

  4. 9 months - Recognise female vs male faces
• Size constancy


  The ability to perceive things accurately when they are the same but look different
• Shape constancy


  The tendency to perceive an object as having the same shape regardless of orientation or angle
• Visual cues for depth perception


  • Height in plane
  • Relative size
  • Superimposition
  • Texture gradient
  • Linear perspective
• Closer objects appear in the bottom half of the visual field, further objects in the top half
• Larger objects appear closer due to relative size
• More of an object is visible when it is closer, less detail is visible when further away (texture gradient)
• Linear perspective, with lines getting narrower towards the top, suggests distance
• Methods for studying perceptual development in babies and animals


  • Observation
  • Habituation
  • Deprivation studies
  • Visual cliff
• Observation


  • Allows inter-rater reliability, but validity and ethics questionable
• Habituation


  • Replicable method, objective measure, but ethics questionable
• Deprivation studies


  • Replicable, valid by comparing dark and light-reared animals, but highly unethical
• Visual cliff


  • Reliable? Possible subjectivity in determining 'crossing', valid?, ethical?
• Gibson & Walk (1960) study


  Tested depth perception in babies and young animals at the stage of independent locomotion
• Babies and most young animals stayed on the centre board or moved to the shallow side
• Dark-reared kittens


  Went onto both deep and shallow sides equally, did not show avoidance of deep side
• Gibson & Walk results


  Suggest depth perception is influenced by both nature (innate) and nurture (learned)
• Gibson & Walk study


  • Hypothesis testing, falsifiable, objective
• Roze/circled back if placed on the deep side
• Dark-reared kittens went onto both sides equally, and did not freeze/circle back if placed on the deep side
• Nature


  Depth perception is present at the point of independent locomotion, which provides some support for it being innate as it is a behaviour that is present very early on in life (e.g. the chicks at 1 day old avoided the deep side)
• Nurture


  However, some learning can still have taken place up to this point. E.g. The babies were 6-14 months old – they will have had lots of experience of having to perceive depth so depth perception could be a learned behaviour
• The researchers tested the hypothesis that babies and young animals would prefer the shallow side to the deep side
• Hypothesis testing


  • The researchers tested the hypothesis that babies and young animals would prefer the shallow side to the deep side
• Falsifiability


  • The hypothesis that depth perception is innate can be both proven right and wrong, and is therefore falsifiable
• Objectivity


  • Whether the babies crossed/didn't cross should be an objective measure, although there could be an element of subjectivity – e.g. what if a baby reached an arm out to the deep side, then retracted back?
• Replicability


  • All children and young animals tested using the same visual cliff equipment so highly replicable
• Mothers will have inevitably behaved differently when calling out to their children from the deep side

  This lowers replicability
• Researchers will have tried to treat all animal subjects the same (i.e. placing them on the centre board in the same way)


  But it is unlikely they will have done this in exactly the same way across all the animals
• Face validity


  • It seems to make sense that if the baby/animal doesn't cross to the deep side that this means they can perceive depth