Tools underfoot: Human trampling as an agent of lithic artifact edge modification

A series of eight replication experiments tests the proposition that human trampling of stone flakes can produce edge damage that mimics deliberate retouch. Retouchlike edge damage, breakage, and other forms of macroscopic mechanical damage were observed on large numbers of pieces in all trampled sets. Experiments measured the relative contributions of three variables-raw material, artifact density, and substrate-in generating damage. Results indicate that while all three factors contribute to some degree, substrate plays the most decisive role, and that artifacts are more likely to exhibit damage if trampled on an impenetrable substrate. It was further found that trampling transforms flakes into pseudo-tools that can be classified as formal tools using a standard typology. Many of these are notched and denticulate pieces, indicating that special caution is needed in behavioral interpretations based on these tool types, and that the European Paleolithic Denticulate Mousterian industry requires critical reassessment.