Computational neuroscience began in the 1930s and 1940s with two groups of researchers. The first group consisted of Alan Turing, Alonzo Church and John von Neumann, who were working to develop computing machines and the mathematical underpinnings of computer science. This work culminated in the theoretical development of so-called Turing machines and the Church–Turing thesis, which formalized the mathematics underlying computability theory. The second group consisted of Warren McCulloch and Walter Pitts who were working to develop the first artificial neural networks. McCulloch and Pitts were the first to hypothesize that neurons could be used to implement a logical calculus that could explain cognition. They used their toy neurons to develop logic gates that could make computations. However these developments failed to take hold in the psychological sciences and neuroscience until the mid-1950s and 1960s.