The Quarterly Journal of Experimental Psychology vol:69 issue:4 pages:728-751
When solving a simple probabilistic problem, people tend to build an incomplete mental representation. We observe this pattern in responses to probabilistic problems over a set of premises using the conjunction, disjunction and conditional propositional connectives. The Mental Model Theory of Extensional Reasoning explains this bias towards underestimating the number of possibilities: In reckoning with different interpretations of the premises (logical rules, mental model theoretical, and specific to conditional premises, conjunction and biconditional interpretation) the Mental Model Theory accounts for the majority of observations. Different interpretations of a premise result in a build-up of mental models that are often incomplete. These mental models are processed using either an extensional strategy relying on proportions amongst models, or a conflict monitoring strategy. The consequence of considering too few possibilities is an erroneous probability estimate akin to that faced by decision makers who fail to generate and consider all alternatives, a characteristic of bounded rationality. We compare our results to the results published Johnson-Laird, Legrenzi, Girotto, Legrenzi, and Caverni (1999), and observe lower performance levels than in the original article.