THE VISUAL CLIFF! A man that went by the name S.B for short was a man that had a corneal transplant completed. Once completed, doctors quickly realized that he didn’t perceive depth like the rest of us. This allowed the argument of perceptual abilities being innate or learned to kick off. Two psychologists by the names of Gibson and Walker decided to perform an experiment involving a visual cliff in 1960. They set out to prove that perceptual abilities were innate and not learned. Logic quickly told these researchers that they can’t just put humans/animals at the edge of a cliff and be considered a humane study.
THE METHOD That lead to the two creating a table that stood
approximately 4 ft tall by 8ft wide. This table
consisted of thick, clear glass, directly under half of the table was a red and white checkered pattern. On the other half there was the same pattern, but it was at the floor level, and a 12 in board in the middle. This created the illusion of a cliff and a “shallow” side.
THE FINDINGS The experiment started with the testing of 36 children that ranged from the ages of 6 months to 14 months of age. The test started with the kids being placed on the 12 in. board, and their mother calling them from the deep side, then the shallow side. Nine of the children in this study refused to move from the board in the middle of the table, the researchers referred to this as the stubbornness of the children. 27 of the children moved across the glass onto the shallow side, with only 3 of the children, with hesitation, went over the “cliff.” On top of testing the children, they wanted to see how different animals of different species reacted to this test as well. They tested a bunch of different animals from rats, chicks,
kids (baby goats), pigs, kitten, puppies and many more. The reason they wanted to study animals, is due to the fact their motor skills develop much quicker than that of humans. The chicks were placed on the table 24 hours after birth and immediately recognized the depth and would not go in that direction. The lambs acted the same way as the chicks, and they were visibly terrified of the deep side on the table. This allows for the argument that depth perception is present at birth. The turtles were the worst performers out of every species tested. This test is widely respected throughout the field, but it was still not able to definitively prove that perceptual abilities were nature over nurture. The inventiveness of Gibson and Walker allows researchers to study depth perception in a clear and systematic way.