Do Orangutans Share Early Human Interest in Odd Objects?

Abstract

Archaeological discoveries suggest that human interest in odd objects emerged as early as the end of the Lower Paleolithic with Homo erectus, although it is still difficult to understand why early humans collected these objects. Several studies show that nonhuman primates are able to appreciate the physical characteristics of their tools, but their interest in the physical properties of nonutilitarian objects has, to our knowledge, never been tested. Here, objects of different brightness, color, and shape were proposed to five orangutans to test whether odd objects intrigue orangutans (Pongo pygmaeus) and whether they induce specific and noticeable behavior. This preliminary experiment shows that orangutans are responsive to the physical properties of nonutilitarian objects, particularly visually striking, bright, and colorful objects. Our experiment shows that these are the most manipulated pieces, regardless of their respective proportions. However, unlike (early) humans, orangutans did not show any ten...