Spatial Representation, Modified by Ecology

Abstract

Performance with the Kohs Block Design and Face Drawing Tests were assessed in two ecologically distinct groups of healthy Indonesians: 196 urbanized subjects and 130 near "hunter-gatherers" (Dani and Asmat from inland West New Guinea). Analysis of subjects' error patterns on the block design construction tasks revealed disproportionally and significantly higher percentages of "nonrandom" configuration-preserving errors by Dani and Asmat subjects (22.18%) than by urbanized subjects, whose errors were fewer but significantly more random and unrelated to the target design. Relations, ratios, and orientation among features within a design pattern tended to be neglected by the Dani and Asmat but rarely by the urbanized subjects (9.78%). On the face drawing task, 81% of Asmat and Dani subjects drew schematized versions (the "neolithic" face pattern), whereas only 39% of urbanized subjects did so. Results suggest that the impact of ecological context on neuropsychologic functioning is profound, influencing even basic visuospatial cognitive processing.