Conflict theory has its roots in the writings of Karl Marx, who asserted that capitalist society breeds hostility between two antagonistic classes which results in crime. This theory postulates that police officers are assaulted when their responsiblities require them to intervene in class-based tensions and hostility. Other research has indicated that ecological factors, namely the stresses and strains associated with lower-class life, contribute to a disproportionate crime rate in lower-class areas and a high incidence of assault on officers. In addition, lower-class subcultural values which encourage violence tend to perpetuate assaults on police. Various interactionist variables including the relationships between police and the general population, psychological motivations for assault, and manner of interaction in police- citizen encounters also help determine violent versus non- violent outcomes. 20 references (Author abstract modified)