Johnson, E. 1 & Tubau, E. 1, 2
1 Departament de Psicologia Bàsica, Universitat de Barcelona, Barcelona, Spain
2 Institute for Brain, Cognition and Behavior, Universitat de Barcelona, Barcelona, Spain
Understanding probabilistic information is essential for success in school and in the job market, as well as for making good health and financial decisions. Despite its importance, probabilistic reasoning remains difficult even for mathematically informed university students. Recent studies have shown that individual differences in numeracy modulate the effects of numerical format in the context of risk perception, decision-making, and Bayesian reasoning. Inconsistent results have been found, however, in the direction of this interaction, with frequency formats sometimes benefiting those higher in numeracy and at other times facilitating performance for the less numerate. The present research addresses these inconsistencies through a series of Bayesian reasoning problems differing in numerical complexity, a standard measure of numeracy, and a number comparison task thought to index basic numerical representation. Extending previous studies using the same numeracy scale, results reveal an interaction between individual numeracy and problem structure: the effect of numeracy only clearly arises in problems involving more complex numerical relations. Preliminary results also indicate that higher-level probabilistic reasoning ability can be at least partially explained in terms of basic numerical representation. Accordingly, the current research provides a more complete account of the role of individual numerical ability in reasoning with probabilistic information.