End state copying by humans (Homo sapiens): implications for a comparative perspective on cumulative culture.

It has been proposed that the uniqueness of human cumulative culture may be attributable to humans' greater orientation toward copying the process of behavior (imitation), as compared with the products (emulation), resulting in particularly high fidelity transmission. Following from previous work indicating that adult human participants can exhibit cumulative learning on the basis of product copying alone, we now investigate whether such learning involves high fidelity transmission. Eighty adult human (Homo sapiens) participants were presented with a task previously shown to elicit cumulative learning under experimental conditions, which involved building a tower from spaghetti and modeling clay. Each participant was shown two completed towers, ostensibly built by previous participants, but actually built to prespecified designs by the experimenter. This end state information was provided either in the form of photographs, or the presence of actual towers. High fidelity matching to these end states was apparent in both demonstration conditions, even for a design that was demonstrably suboptimal with regard to the goal of the task (maximizing tower height). We conclude that, although high fidelity transmission is likely to be implicated in cumulative culture, action copying is not always necessary for this to occur. Furthermore, since chimpanzees apparently copy behavioral processes and well as products, and also transmit behavior with high fidelity, the stark absence of unequivocal examples of cumulative culture in nonhumans may be attributable to factors other than imitative ability.