Introduction: In the late 1950s and early 1960s, an anthropologist, C.M. Turnbull, travelled to the Ituri Forest in the present-day country of the Democratic Republic of the Congo (formerly Zaire) to study the life and culture of the BaMbuti Pygmies. Turnbull travelled from one village to another. A 22-year-old man named Kenge from a local Pygmy village accompanied and assisted him. Kenge had spent all of his life living in the dense forests surrounding his village. He was accustomed to seeing only the images contained within the forests. 

Hypothesis: Because Kenge had been isolated by the forests all of his life, the sight of new images would appear complex and confusing. The thick forests blocked the local villagers view of distant objects such as animals, mountains, and the sun and moon on the horizon. Because Kenge had never seen these things, his perceptual development (in this case, size constancy, or the ability to perceive a familiar object as being the same size regardless of its distance from you) was limited. He understood only what he could see directly in front of him. The information collected from Turnbulls experience with Kenge raised the question of whether perceptual understanding is a learned ability or biological mechanism: a question of nature versus nurture.

 

Method: The discovery of Kenges perceptual limitations took place when Turnbull and Kenge came to a clearing on the eastern edge of the Ituri Forest. At that point Kenge and Turnbull enjoyed a clear view of the Ruwenzori Mountains. Confused by the sight of the mountains, Kenge asked Turnbull if the mountains were hills or clouds. Turnbull explained that they were hills but much larger than any Kenge had seen before. Kenge agreed to ride with Turnbull to the mountains for further inspection. A passing thunderstorm obstructed the travelers view and did not clear until the two reached the mountains. When Kenge peered up at the enormous mountain range, he was amazed.

 

As Turnbull and Kenge turned to leave, Kenge noticed a wide open plain on which stood a herd of buffalo. Kenge wanted to know what type of insects the buffalo were. Turnbull explained that the animals were not insects but buffalo. When the two arrived close to the herd of buffalo, Kenge now knew that the insects were buffalo all along, but he still could not understand why they had appeared to be so small.

 

Results: Turnbulls accounts support the idea that human perception develops (at least in the case of size constancy) as we use the environment around us, or by nurture. However, some research with infants supports the nature side of perception. For example, individuals who were blind at birth and later gained their sight were able to perceive figure-ground relationships. Are we born with certain perceptual abilities and not others, or is perception something we learn? In Kenges case, perceptual ability was a learned phenomenon. Certain perceptual skills may be necessary for our survival. In Kenges case, he did not need a wide range of size constancy to survive in the dense jungle.

 

 

 

Analyzing the Case Study 

 

1. Why did some images seem confusing to Kenge? 

 

2. According to Turnbull, how do we learn size constancy? 

 

3. Critical Thinking Do you think that Kenge could adjust to life in your city or town? Explain the difficulties he might encounter.