YACS: A new learning classifier system using anticipation. A new and original trend in the Learning Classifier System (LCS) framework is focussed on latent learning. These new LCSs call upon classifiers with a ( condition ), an ( action ) and an ( effect ) part. In psychology, latent learning is defined as learning without getting any kind of reward. In the LCS framework, this process is in charge of discovering classifiers which are able to anticipate accurately the consequences of actions under some conditions. Accordingly, the latent learning process builds a model of the dynamics of the environment. This model can be used to improve the policy learning process. This paper describes YACS, a new LCS performing latent learning, and compares it with ACS.