Melpa-speaking children do very poorly on cognitive tasks, in general, and as compared to children from another traditional society in Papua New Guinea. Causes for this difference are sought in an analysis of the tasks which shows them to require a taxonomic strategy for successful performance and in an analysis of the folk taxonomies of the respective societies which shows them to vary in complexity. Further study of Melpa representation reveals that this can better be represented as a pairing rather than a taxonomizing tendency This finding allows a reinterpretation of the cognitive task results.