All organisms receive signals from environment and perform appropriate behavior. The evolution of optimal behavior for signals have been discussed in signal detection theory and decision theory (Willey 1994). However many organisms can remember and learn signals and they can change their behavior to the same signals. Some mathematical model about signal learning are also reported (Sherratt 2011), but there are no discussion about the relationship between evolution and learning. In this presentation, I talk about the model which explains behavior against repeated signals including both evolution and learning. I compare the results with past models and discuss the relationships between evolutionary models and learning models.