Two additional articles, one comparing aggressiveness between men and women and the other examining the propensity for peacefulness in humans, have been added to the article archive in this website.

Douglas Fry, comparing the nature and extent of violence among Zapotec women and men in 1992 found that the women tended to use more indirect approaches to aggressiveness than men do. He reviewed other literature about the Zapotec people and from other cultures in his examination of male and female violence.

Four years later, Leslie Sponsel published a thorough review of the literature from ethology, paleontology, archaeology, and ethnology that related to the role of peace and peacefulness in human societies. He found that, while violence in history and the contemporary world is obvious and cannot be denied, the extensive evidence about peacefulness in many scientific disciplines shows that human societies can also be peaceful—that violence is not inevitable. The literature about the peaceful societies plays an important role in his analysis.