HOW TO IMPROVE BAYESIAN REASONING WITHOUT INSTRUCTION - FREQUENCY FORMATS

Is the mind, by design, predisposed against performing Bayesian infere nce? Previous research on base rate neglect suggests that the mind lac ks the appropriate cognitive algorithms. However, any claim against th e existence of an algorithm, Bayesian or otherwise, is impossible to e valuate unless one specifies the information format in which it is des igned to operate. The authors show that Bayesian algorithms are comput ationally simpler in frequency formats than in the probability formats used in previous research. Frequency formats correspond to the sequen tial way information is acquired in natural sampling, from animal fora ging to neural networks. By analyzing several thousand solutions to Ba yesian problems, the authors found that when information was presented in frequency formats, statistically naive participants derived up to 50% of all inferences by Bayesian algorithms. Non-Bayesian algorithms included simple versions of Fisherian and Neyman-Pearsonian inference.