Artificial intelligence (AI) is a computer-based model of intellectual processes. AI scientists build computer programs to simulate human intelligence. Their implicit assumption is that psychology can be reduced to mathematical algorithms, the set of mathematical rules from which computer programs are built. As of yet, AI has been restricted to relatively simple aspects of human psychology, such as visual perception and object recognition. Nonetheless, AI models have become increasingly sophisticated and have taken on the complex problem of learning. How can a computer program modify itself in the face of new information? Pattern recognition software depends on a kind of teaching. The programs are designed to respond to incoming feedback from the outside world. Responses that are reinforced are strengthened and those that are not reinforced are weakened. In this way, AI is similar to the both behaviorist and evolutionary models of psychology.