Humans do lots of things that make them unique among living beings. What properties of our species explain its uniqueness? While there may never be a complete answer to this question, and certainly there is not one single answer, progress has been made to try to characterize some of them. Here, we focus on the ability to take decisions under (strategic) uncertainty, and on our understanding of their neural basis. We will then explore whether signatures exist for the presence of some primitives of reasoning, perhaps already available in early infancy, which ground the ability to represent the world, conceive alternative situations, frame hypothesis, think and solve problems.