The Measurement of Factive Deductivity: a Psychological and Cerebral Review

Abstract

There are normative differences between deduction and induction, but are there factual differences between them? The state of the art offers all logically possi- ble answers to this question. Let the Hypothesis of Factive Deduction state that one and the same deductive phenomenon occurs at normative, psychological and neural levels. A systematic review of psychometrical and neural tests was conducted in the search for measures to empirically confirm or refute the Hypothesis. The review iden- tified 27 psychometrical and 58 neural measures of which 15 psychometrical and 16 neural tests met criteria for inclusion. Deductive properties such as: logical validity, probabilistic validity, logical vs. relational complexity, format invariance, computabil- ity, integration and formality level have been operationalized. For any given deductive component, we determine if it is measured, explicitly assessed, present or absent in each test. Results show the absence of deductive measures and the presence of in- consistent constructs corresponding to distinct notions of deduction. Non-explicitly deductive components (microdeductions) in reasoning tests are identified. The intro- duced deductive variables intend to contribute to a future confirmation or refutation of the Factive Deduction Hypothesis.