From reading Tierney's article "Darkness in El Dorado" the main problems is in how Chagnon conducted his research. He has been accused of using bribery and questionable trade tactics in order to obtain information from the Yanonami people. Much of this information, such as names of dead relatives, was seen as taboo in the culture, and many villagers had to go against their customs in order to do this. Chagnon states that he is going into these villages in order to only observe the peoples and their customs, however he seems to be doing a lot of instigating and causing more problems. Tierney puts out many different accusations, many of which may be exaggerated, but if there is some truth in his research than Chagnon has definitely overstepped his boundaries with the Yanonami.