We do not understand the way neural circuitry works. One of the chief lacks is the understanding of reverberation. A second lack is understanding the dynamics of learning and how this is affected by reverberation. CAs use reverberation and learning, so CAs can be used to study them. By simulating computational and psychological tasks with networks of neurons that have CAs, we can better understand human intelligence. Moreover, by understanding systems of CAs we can build systems with novel capabilities.