Four experiments comparing behavior of children from Los Angeles, California, and Nuevo San Vicente, Baja California, Mexico, were conducted to analyze cooperative and competitive behavior of Anglo American city and Mexican rural children. Eighty children from each setting, 40 of age 7-9 and 40 of age 10-11, equally divided by sex, served as subjects for all 4 experiments. Results of Experiment I, which was designed to assess motivation and ability of children to cooperate in a problem situation with no obvious conflict of interest cues, failed to support the hypothesis of a cultural difference in motivation and ability to cooperate. In Experiment II, which assessed the degree to which children are competitive and rivalrous in a situation without direct social interaction and the necessity of mutual assistance, both groups appeared highly motivated to take a toy away from a peer when they could keep it. Anglo children, however, were more highly motivated than Mexican children to lower another child's outcomes, even when it meant no gain to themselves. In Experiment III, which examined rivalrous behavior in the presence of direct social interaction, Anglo more than Mexican children responded with conflict to a peer's rivalrous intents in an interpersonal interaction situation; Mexican children were more submissive. In Experiment IV, which measured tendencies to engage in and avoid direct interpersonal conflict, Mexican children were more avoidant of conflict than Anglo children. (Author/NQ)