The episode also showed a clip of a fight in a Yanomami village from the film The Ax Fight by Napoleon Chagnon and Tim Asch. According to Chagnon the fight is an example of the impact of kin selection on humans, since the people fighting chose sides on the basis of kinship. Curtis interviews Chagnon and puts to him the assertion of fellow anthropologist Brian Ferguson that much of the Yanamamo violence, particularly its intensity, was very strongly influenced by the presence of Westerners handing out goods which the tribesmen fought over; in this case the goods were highly prized and useful machetes. Chagnon, however, insists that his presence had had no influence whatsoever on the situation, citing the fact that similar fights happened when he wasn't present, which he also documented through informants. Curtis asked, "You don't think a film crew in the middle of a fight in a village has an effect?" Chagnon replied, "No, I don't," and immediately stopped the interview.