Johanna Eckert: University of California, Los Angeles

Intuitive statistics is the capacity to draw intuitive probabilistic inferences based on an understanding of the relations between populations, sampling processes, and resulting samples. This capacity is fundamental to our daily lives and one of the hallmarks of human thinking. We constantly use sample observations to draw general conclusions about the world, use these generalizations to predict what will happen next and to make rational decisions under uncertainty. Historically, statistical reasoning was thought to develop late in ontogeny and to remain error-prone throughout adulthood. In the last decade, however, evidence has accumulated from developmental research showing that even pre-verbal infants can reason from populations of items to randomly drawn samples and vice versa. These new insights raise a fundamental question concerning the phylogenetic origins of intuitive statistics: Is it a uniquely human capacity, perhaps accounting for our unprecedented cognitive flexibility? Or do we share it with other animals, most notably our closest living relatives, the nonhuman great apes? We adapted a paradigm previously used in developmental research to study intuitive statistical abilities in sanctuary- and zoo-living apes. Specifically, we explored the generality and flexibility of apes´ statistical capacities, their cognitive structures and limits, and their interaction with knowledge from other cognitive domains. Our findings indicate that apes possess statistical capacities on a par with those of human infants. Intuitive statistics, therefore, antedate language and mathematical thinking not only ontogenetically, but also phylogenetically. Hence, humans´ statistical abilities are most likely founded on an evolutionary ancient capacity shared with our closest living relatives.