when does a baby's vision fully develop
Infant visual development One of the important discoveries of infant depth perception is thanks to researchers Eleanor J. Gibson and R.D. Walk.[18] Gibson and Walk developed an apparatus called the visual cliff that could be used to investigate visual depth perception in infants. In short, infants were placed on a centerboard to one side which contained an illusory steep drop (“deep side”) and another which contained a platform of the centerboard (“shallow side”). In reality, both sides, covered in glass, was safe for infants to trek. From their experiment, Gibson and Walk found that a majority of infants ranging from 6–14 months-old would not cross from the shallow side to the deep side due to their innate sense of fear to heights. From this experiment, Gibson and Walk concluded that by six months an infant has developed a sense of depth. However, this experiment was limited to infants that could independently crawl or walk.[18] To overcome the limitations of testing non-locomotive infants, Campos and his colleges devised an experiment that was dependent on heart rate reactions of infants when placed in environments that reflected different depth scenarios. Campos and his colleagues placed six week-old infants on the “deep end” of the visual cliff, the six week-old infants' heart rate decreased and a sense of fascination was seen in the infants. However, when seven month-old infants were lowered down on the same “deep end” illusion, their heart rates accelerated rapidly and they started to whimper. Gibson and Walk concluded that infants had developed a sense of visual depth prior to beginning locomotion. Therefore, it could be concluded that sometime at the spark of crawling around 4–5 months, depth perception begins to strongly present itself.[19]