Child Topic 3 Flashcards
Gibson & walk aims
To see if depth perception is learnt or innate. Whether it occurs before/ after ability to move independently & variations in different species. To se if motion parallax or pattern density is more important in depth perception.
Method
Lab experiment, repeated measures. IV= mum calls from deep or shallow side. DV= crawling across visual cliff. Animal study is a quasi experiment
Sample
36 6-14 month old crawling babies, chicks, lambs, kids, piglets, puppies etc
Materials
Visual cliff table 1 metre high, red & white chequered pattern attached to the floor & underside of half the glass.
Procedure
Babies placed on centreboard individually, mums called from deep or shallow side. Animals placed on raised centreboard to see which side they would step on
Controls
1- Pattern density (PD) controlled by increasing deep side square size.
2- Motion parallax (MP) controlled by making shallow side squares bigger so they appeared closer.
MP= close things move faster than far things, PD= far things have less detail
Results
-3/37 babies crawled on deep side, 9 refused to move, 27 crawled on shallow side. Many cried in frustration about the deep side, kids, lambs, chicks refused deep side or froze if placed on it.
- Hooded rats= no preference and use whiskers to perceive. Normal rats 95% shallow side
Conclusions
- depth perception has an evolutionary advantage (safety) there is an innate predisposition to develop it by the time of independent locomotion, too risky to be left to trial & error learning.
- precocial animals have it innate from birth, altricial animals develop it when mobile, so its dependent on a species ecological niche.
- can’t prove depth perception is innate in humans as exp requires them to crawl; 6 months= could have learned depth perception in this time. Human depth perception occurs before controlled movement= risky to leave babies
