The success of graphic models to visualize conditional probabilities

Why is training of conditional probabilities necessary? - Conditional probabilities play an important role within the statistics curriculum and in decision making under uncertainty (Bayesian inference). - People often have problems to use conditional probabilities in the right way (many examples in the literature of cognitive psychology). So it is important that - although there exist a lot of didactical suggestions - there has been no empirical research dealing especially with the improvement of the understanding of conditional probabilities. So we made a first try to close this gap.