When asked to solve a problem, the adolescent can imagine many possible solutions to the problem. These imagined solutions are called hypotheses. Adolescents can then plan ways to test each of those hypotheses. This kind of reasoning from the hypothetical is known as hypothetico-deductive reasoning and is the same kind of reasoning used in scientific experiments. This newfound ability allows adolescents to use systematic planning when solving problems. In contrast, children in the concrete operational stage are more likely to problem solve through trial and error. They reason from the actual, not the hypothetical.