1 On Weapons, Combat, and Ecology.- On Some Strategies of Overt Aggression.- Reproduction and Resources.- Weapons and Defenses.- Retaliation as a Control on the Evolution of Agonistic Behavior and Organs.- Threats and Displays.- Attention Fixation and Guidance.- Weapons, Defenses, and Displays in Relation to Ecological Adaptive Strategies.- Summary.- References.- 2 Communication Mechanisms in New World Primates with Special Reference to Vocalizations in the Black Spider Monkey (Ateles fusciceps robustus).- The Complexity of Communication Systems and the Auditory Channel.- The Natural History of Ateles.- Nonauditory Communication.- The Analysis of Auditory Communication.- The Problem of Comparative Studies.- Chorusing and Group Synchrony.- Discussion and Summary.- References.- 3 Aggression, Dispersal, and Cyclic Changes in Populations of Small Rodents.- Fence Effect.- Pulsed Removal Experiment.- Methods.- Results.- Discussion.- Summary.- References.- 4 Bird Song and Territorial Behavior.- Territory.- The Role of Song.- Evidence of the Sexual Function of Song.- Evidence of the Territorial Function of Song.- Information Communicated by Song.- Species Recognition.- Individual Recognition.- Features of Song Used in Recognition.- Repertoires.- Conclusion.- References.- 5 Crowding and Behavior: The Effects of High Density on Human Behavior and Emotions.- Effects on Animals.- Experimental Research on People.- Crowding and Social Behavior.- Crowding Intensifies Responses.- Crowding and Laughter.- Crowding and Crime.- Summary and Implications.- References.- 6 Preschool Social Organization: Agonistic, Spacing, and Attentional Behaviors.- Aggression, Conflict, and Social Dominance.- The Langara Project.- The Waterloo Project.- The Arbor Hill Project.- Social Dominance and Proximity.- Social Attention, Dominance, and Proximity.- Attention and Proximity.- Attention and Rank.- Function and Importance of Attention.- Summary.- References.- 7 Communication, Affect, and Social Behavior.- Emotions as Ritual Displays.- Judgment of Emotions.- Relations among Emotions.- Topography of Expression.- Structure of Social Behavior.- Appendix: Behavior Inventory.- Facial Expression.- Utterances.- Contact Behaviors.- Other Behaviors.- References.- 8 The Psychology of Evil: On the Perversion of Human Potential.- Empirical Research on Evil.- Dispositional versus Situational Attribution.- Seven Unpleasant Thoughts.- The Banality of Evil.- Blind Obedience to Authority.- Obedience in Real World Settings.- Anonymity and Aggression.- Vandalism.- The Evil of Inaction.- Justifying Evil Deeds.- The Evil of Roles and Rules in a Prison.- The Final Solution Revisited.- Business as Usual.- An Optimistic Conclusion after All That?.- Appendix: Ways We Can Go Wrong.- References.