One of the most important features of the human mind is its ability to make generalisations based on sparse data. Our brain accomplishes this task by using probability information to represent statistical regularities in our environment and guiding our actions. As adults, we have a vague understanding of which events are likely to happen. But so far, it has not been clear when in our lifespan we begin to estimate which events are more likely to occur than others. Scientists at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in Leipzig have now shown that even six-month-old babies have a sense of probability.