Differences in mental representations spontaneously adopted for reasoning

Retrospective reporting was used to show that people spontaneously adopt different mental representations for reasoning. In two experiments, subjects solved a large number of threeterm series reasoning problems and then gave retrospective reports (verbal protocols, drawings, and forced-choice strategy selections) about their solutions. A majority of subjects’ reports could be classified reliably into two groups. One group (abstract directional thinkers) claimed to construct a mental ordering of the three geometric figures used as the terms in the problems. A second group (concrete properties thinkers) claimed to attribute physical properties to mental geometric objects. In both experiments, abstract directional thinkers made few errors and were sensitive to the number of pivot-first premises in a problem. Concrete properties thinkers made more errors and were sensitive to the use of inverse relations and the number of alternations between a relation and its inverse as a problem was read. Quantitative models of the two kinds of reasoning are presented. Implications are discussed concerning theories of reasoning, tests of reasoning, and the usefulness of retrospective reporting as a general method.