Jason Shogren, Richard Horan, and Erwin Bulte argue that free trade contributed to humans’ outcompeting Neanderthals.

Archaeological evidence exists to suggest traveling bands of early humans interacted with each other and that inter-group trading emerged, says Shogren. Early humans, the Aurignations and the Gravettians, imported many raw materials over long ranges and their innovations were widely dispersed. Such exchanges of goods and ideas helped early humans to develop “supergroup social mechanisms.” The long-range interchange among different groups kept both cultures going and generated new cultural explosions, Shogren says.

Thanks to Don Boudreaux for the pointer to the summary.

UPDATE: Perry Eidelbus gives this link. The paper has a high ratio of superfluous math to convincing evidence. Also, for more discussion, see Jackson Kuhl.