ABSTRACT
It is widely agreed now that there has been a major paradigm shift in the psychology of deductive reasoning: the general topic area for most of the papers in this book. The field as I entered it c. 1970 was dominated by logic: in fact, a particular kind of standard logic, based on the idea that all propositions are either true or false. Logic was also an unquestioned normative standard for reasoning, as we saw in the previous section on rationality. Experiments were designed specifically to test whether participants untrained in formal logic, could nevertheless make valid deductive inferences. As I write now, early in 2013, the field has a very different look to it both in terms of research methods and theoretical concepts. The majority of researchers in the field now consider that people reason with beliefs held with degrees of uncertainty, or subjective probability. They use a much wider range of research methods and different approaches (if any) to the assessment of rationality. Binary (true/false) logic is no longer the driving concept for the field.
