The ultimate goal of peace education is "to minimise and eventually eliminate various forms of violence through consciousness raising, vision, and action" (Brantmeier, E. (2003) Peace Pedagogy: exposing and integrating peace education in teacher education. Paper presented at the "Association for Teacher Educators" meeting, p. 6). Our position is that we should invest in peace education and prevention of violence by helping preschool children develop cognitive competencies. One of the aspects of cognitive development explored in this text regards children's social representations (SR) of violence. Indeed, a number of psychologists have demonstrated that SR serve to regulate behaviors in relation to social norms, and that a change in a person's SR influences her or his judgments and actions. This study consists of descriptions of children's SR of violence, verifying whether these SR are stable or dynamic at the ages of five and six years, and whether children are or are not stimulated by the Philosophy for Children approach used throughout one school year. Firstly, the results indicate that children's SR of violence can be grouped into four hierarchical perspectives. Secondly, the results indicate that the SR of children in the control groups hardly changed during the year, whereas those of children in the experimental groups showed a more marked reorganization. (Contains 8 tables and 3 notes.)