The purpose of this study was to determine if an effective conservation training procedure would be one in which a child was confronted with opposing points of view. Subjects were 108 children with a mean age of 6.7 years. In two experiments, a group of three children (generally one nonconserver and two conservers) was required to respond with one group answer to a series of standardized conservation problems. When tested again individually, all subjects made significant gains in conservation judgments and explanations on the same problems, on a parallel form of those problems, and on new problems. Nonconservers made the greatest gains. Conservation was found to be related to an analytical cognitive style in one study. (Author/AJ)