Perceptual Development: Infant Studies

Perceptual Development: Infant Studies

1. Depth Perception

   • Monocular cues
     • Responsiveness to dynamic cues appears earlier than static cues. For example motion paralax (closer object moves quicker in the field of vision) relies on movement and develops quicker than occlusion (one object blocks another appears closer) which is a depth cue viewed in a stationary position.
     • Gibson and Walk
       • Visual cliff. 6 month old babies refused to crawl to mums if they had to cross an apparent cliff edge. This shows depth perception is innate.
     • Hofsten et al
       • Habituation model (showing infants a display until they get used to it, If shown the same display, they should show less interest).
       • Display of 3 rods, whilst the infant is moving in a chair. The rods were the same distance, but the middle rod moved in synchrony with infants creating motion paralax. 2 further displays were shown, 1 3 rods same distance, 1 3 rods, but middle rod further away.
       • Infants showed more interest in the equidistance rods-showing ability to use motion paralax.
     • Granrud and Yonas
       • Response to depth cues of occlusion developed around 6 months of age.
   • Binocular Cues
     • Use of retinal disparity (closer object=more seperate from both eyes).
     • Different info into each eye of infants, the image appeared 3-D. Infants as young as 1 week old tried to grab the object-showing depth perception based on retinal disparity..
   • Age-Related Changes
     • Yonas et al
       • Infants shown 2 toys,equidistance. One appeared closer because of added shadows. 1 eye was also covered to remove binocular information for depth.
       • Older infants were more likely to reach towards seemingly closer object than younger infants-ability to use shadows as depth develops with age.

2. Visual Constancy

   • Shape Constancy
     • Bower
       • Operant conditioning-infants rewarded when viewed one object, so should prefer it in the future.
       • Age 2 months conditioned prefer rectangle slanted at 45 degree angle, so looked like trapezoid. Also, shown other objects.
       • Infants prefered rectangle to trapezoid-showing shape constancy.
   • Size Constancy
     • Slater et al
       • Habituation model. Newborns shown series of cubes to habituate them to cubes. Then shown cubes side-by-side, larger one more distant so they have the same retinal size.
       • Infants looked longer at the unfamiliarised cube-displaying size constancy.

3. Pattern Perception

   • Brennen et al
     • Showed infants checkerboard patterns increasing complexity.
     • 1 month old preferred simple patterns, whilst 3 month old preferred complex patterns. 
     • Younger infants don't have sufficient visual acuity to see smaller aquares in 24x24 display, but older preference complex visual stimuli.

4. Reliable?

   • Researcher mus come up with ingenious methods, so cannot sure the results are reliable. Infants may be susceptible to experimental bias. Lack of reaction due to tiredness, not habituation?

5. Research Support

   • Research supports the view that perception is innate and bottom-up.

6. Perceptual Completion

   • Ghim
     • Infants couldn't detect kanizsa square  at 2 months old. They're unable to integrate seperate angular features into a square until they are older.
   • Importance of research
     • Supports top-down, but the distinction between top-down and bottom-up may lie in deciding what counts as perceptual development and what counts as cognitive development.

7. IDA-RWA

   • Banks et al-children born with squints don't develop binocular vision, and depth perception is impaired. Thus, research on effects of deprivation has important applicantions in decisions of remedial surgery.

8. IDA-Nature vs. Nurture

   • Blackemore and Cooper-newborn kitten were put into vertical stripe environments. When released into the real world at the age of 5 months, they were seemingly blind to horizontal stripes-showing innate visual mechanisms in the brain are shaped by experience-both nature and nurture.