Sensible Reasoning: A Hypothesis about Hypotheses

Abstract

TsCHmcI, JUDrTH E. Sensible Reasoning: A Hypothesis about Hypotheses. CHILD DEVELOPMENT, 1980, 51, 1-10. This study investigated the asserted differences in reasoning between adults and second, fourth, and sixth graders in a manipulation-of-variables task using common everyday situations. It is proposed that hypothesis-testing skills used in this task do not necessarily develop from an understanding of the logic of classes. These skills may develop through experience in manipulating elements in those naturally occurring situations where it is desirable to eliminate negative outcomes or reproduce positive outcomes. Subjects were given 8 multivariate stories with different outcomes, either good or bad, and asked to choose a test to determine which element caused the outcome. Subjects were expected to choose a test systematically on the basis of considerations of the outcome value of any situation, not on purely logical grounds. For all age groups the general pattern of responses was the same. A logical disconfirming test (vary only the hypothesized variable) was preferred in bad-outcome situations, and a logically inappropriate confirming test (repeat the hypothesized variable in a different context) was preferred in good-outcome stories. The main developmental trend was a shift in choice of strategy to eliminate the hypothesized variable in bad-outcome stories. There was no relation between children's performance on class-inclusion problems and their story-problem solutions. These results are discussed in terms of sensible reasoning and problem-solving skills.