Abstract
Many of the phenomena underlying shape recognition can be derived from an assumption that objects are represented as an arrangement of simple, regular, 2D or 3D geometrical shapes, such as circles, squares, bricks, and cones. The shapes, termed geons, are distinguished by contrasts of nonaccidental properties (NAPs), such as curved vs. straight or parallel vs. not parallel, that are invariant with orientation in depth. The detailed neural connectivity that enables this capacity is believed to develop out of early experience with the visual world. But what comprises this experience? By one assumption, a rich experience with extended contours—a characteristic of all naturally varying (i.e., non laboratory) visual worlds —would be sufficient to develop the appropriate representations. An alternative assumption is that the tendency for geon-like representations derives from our immersion in a manufactured world. Would individuals from a culture with only minimal exposure to developed-world artifacts show the same kinds of perceptual representations as those evidenced by typical artifact-immersed laboratory subjects? Would they, instead, have greater sensitivity for distinguishing among highly irregular shapes, such as bushes? The Himba are a people in northern Namibia with little contact with the regular, simple artifacts so prevalent in the daily life in developed societies. Their language includes few of the terms for the simple shapes and shape characteristics (e.g., “parallel”) common in languages in developed societies. Similar to Western observers, the Himba showed greater sensitivity in distinguished shapes differing in NAPs compared to metric properties (i.e., quantitative variations such as aspect ratio or degree of curvature that do vary with rotation in depth). Moreover, the Himba's sensitivity to variations in shape similarity in distinguishing both simple regular shapes and highly irregular blobs resembled that of Western observers.