  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 article, 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
analyze 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 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.
