Middle School Students’ Approaches to Reasoning about Disconfirming Evidence

This study investigated differences in how middle school children reason about disconfirming evidence. Scientists evaluate hypotheses against evidence, rejecting those that are disconfirmed. Although this instant rationality propels empirical science, it works less for theoretical science, where it is often necessary to delay rationality – to tolerate disconfirming evidence in the short run. We used behavioral measures to identify two groups of middle-school children- strict reasoners who prefer instant rationality and quickly dismiss disconfirmed hypotheses, and permissive reasoners who prefer delayed rationality and retain disconfirmed hypotheses for further evaluation. We measured their scientific reasoning performance as well as their cognitive ability and motivational orientation. What distinguished the groups was not overall differences in these variables, but their predictive relation. For strict reasoners, better scientific reasoning was associated with faster processing, whereas for permissive reasoners, better scientific reasoning was associated with more deliberate thinking – slower processing and broader consideration of both disconfirmed and alternate hypotheses. These findings expand our understanding of “normative” scientific reasoning.