PubMed1998
The paper reported four experiments on explicit standard order conditional selection tasks, which permit more direct inference of subjects' strategies than do other conditional selection tasks. The experiments allowed plausible rational support-seeking strategies to be reduced from nine to three, disproof strategies from six to three. The main strategy in early adolescence was either (1) models-based deduction, as suggested by Johnson-Laird and Byrne in 1991 or (2) rules-based deduction, as suggested by Rips in 1994, with a factual attitude to hypothesis and offered information. In late adolescence a substantial minority adopt a hypothetical attitude to both these things, which may be applied with either of these strategies or with (3) the nondeductive strategy suggested by Langford and Hunting in 1994. This general picture of developmental possibilities can be extended to Inhelder's and Piaget's problems requiring information search to test conditional and biconditional hypotheses, in particular their chemicals, pendulum, and rods problems. This extension is obtained by assuming that adolescents acquire a range of strategies for problems requiring more or less focussed information search, conditional selection tasks requiring the former, Piagetian formal operations tasks tending towards the latter. Current evidence does not indicate whether strategies (1) or (2) are dominant in younger adolescents or whether strategies (1) or (2) or (3) are dominant in older adolescents. Thus, the Piagetian argument that formal operations thinking passes from factual rules-based deduction to hypothetical rules-based deduction is only one of several styles of theory that can readily accommodate current evidence in this area.