Professor Steve Wisecarver
October 25, 2010
(a) Date published – 1960
(b) Volume number – 202(4)
(c) Title of article – The “Visual Cliff”
(d) Journal (or book) – Scientific American
(e) Name of author(s) – Gibson, E.J. & Walk, R.D.
(f) Page Numbers – 67-71
The purpose of this study was to determine what point in the development process one is able to perceive depth; and to decide whether this ability is learned, or given at birth. Some assumed that this skill is known at birth, as a survival instinct. But the researchers pointed out the idea that infants are known to be prone to falls. They decided a way to conduct a test for this would be to put them on the edge of a cliff, and see if they would be able to avoid falling off. Of course for ethical reasons, they couldn’t use a real cliff. So they came up with a mechanism known as the visual cliff. It uses what appears to be a drop off, when there actually isn’t. The reason this is used, is both animals and humans can be placed on this to see if they can perceive depth. But, if they are unable to do so, there is no danger for fall. Gibson and Walk believe on this topic that depth perception of a drop off is known from birth, and not learned as the opposing, empiricist view. This allowed them to ask how the subject could react to the stimuli of depth, or a fall.
The subjects used for this test were a group of 36 infants, aged between 6 and 14 months. As well as the infants, their mothers also participated in aid. As well as human infants, baby animals were also used. They ranged between chicks, turtles, rats, lambs, baby goats, pigs, kittens, and also puppies. The reason these subjects were used, is whether human or animal, infants cannot be asked whether or not they perceive depth.
The method used was rather simple. It was composed of a table about 4 feet high, with a top made of clear, thick glass. It had both a “deep” side, and a “shallow” side....