Analysing the Conjunction Fallacy as a Fact

Since the seminal paper by Tversky and Kahneman, the ‘conjunction fallacy’ has been the subject of multiple debates and become a fundamental challenge for cognitive theories in decision-making. In this chapter, we take a rather uncommon perspective on this phenomenon. Instead of trying to explain the nature or causes of the conjunction fallacy (intensional definition), we analyse its range of factual possibilities (extensional definition). We show that the majority of research on the conjunction fallacy, according to our sample of experiments reviewed which covers the literature between 1983 and 2016, has focused on a narrow part of the a priori factual possibilities, implying that explanations of the conjunction fallacy are fundamentally biased by the short scope of possibilities explored. The latter is a rather curious aspect of the research evolution in the conjunction fallacy considering that the very nature of it is motivated by extensional considerations.