Certain kinds of learning are characterized by the fact that they occur only during a specific — and often brief — period of the animal’s lifetime. Furthermore, these kinds of learning have rather dramatic and long-lasting effects on the animal’s subsequent behavior and lifestyle. This kind of learning is generally known as phase-specific learning, in that the behavior changes incurred by it are acquired during what appears to be a well-defined sensitive period of the animal’s development. The effects are durable, often resistant to subsequent manipulation and appear to play an important role in determining many of the animal’s long-term preferences.