Waorani life histories challenge benefits of aggression.
Among some isolated South American indigenous groups, aggressive, vengeful behavior was seen as the way for men to gain status and family. Now an international team of anthropologists says the macho guy does not always get the girl.
"In 1988, Napoleon Chagnon published evidence that among the famously warlike Yanomamo of Venezuela, men who had participated in a homicide had significantly more wives and children than their less warlike brethren," says Stephen Beckerman, associate professor of anthropology at Penn State. Working among the Waorani of Ecuador, however, Beckerman and colleagues have found the opposite to be true.
The Waorani forage and grow manioc in the lush rainforest of the Amazon basin. At their first peaceful contact with the outside world, in 1958, they numbered about 500 people, and were known to be even more bellicose than the Yanomamo. Warfare and murder were common, and they practiced their violence on each other as well as on outsiders. Over a period of 14 years, missionaries pacified the entire population, to the point where aggressive warfare and raiding are now almost gone.
Courtesy Stephen Beckerman
For the Waorani Life History Project, Beckerman and his colleagues interviewed 95 men in 23 settlements, including any man old enough to have experienced warfare before the pacification. They collected genealogies, reproductive history, warfare history, and individual life stories. Their findings? More aggressive men did not acquire more wives than milder men. They did not have more children, and their wives and children did not survive longer. In fact, warlike men had fewer children who survived to reproductive age.
Why did aggression and warlike behavior work for Yanomamo men, but not for the Waorani? One cultural difference suggests a clue. While both the Yanomamo and the Waorani used violence for revenge, the researchers say, the Yanomamo's warfare cycles had peaceful interludes during which warriors could reap the benefits of battle, and accrue wives and children. The Waorani men, in contrast, did not incorporate these lulls. Waorani were even known to initiate fresh mayhem based on something that had occurred in their grandparent's generation.
No doubt as a result, another difference between the Yanomamo and the Waorani is that even with chronic warfare, the Yanomamo population had grown over the two centuries before Chagnon's investigation. In contrast, "The Waorani, as far as we could tell, were well along in the process of killing themselves off at the time of peaceful contact," Beckerman says.
Stephen Beckerman, Ph.D., is associate professor of anthropology at Penn State; stv@psu.edu. Other researchers involved in the Waorani Life History Project are Pamela I. Erickson of the University of Connecticut; James Yost; Jhanira Regalado of the Museo de Historia Natural, Escuela Politécnica Nacional, Ecuador; Lilia Jaramillo of the Carretera Panamericana, Cotopaxi, Ecuador; Corey Sparks of the University of Texas, San Antonio; Moises Iromenga of the Organización de la Nacionalidad Huaorani de la Amazonia Ecuatoriana, Ecuador; and Kathryn Long of Wheaton College.
The National Science Foundation supported this work, which was reported in the Proceedings of the National Academy of Science on May 19, 2009.
