The structure of all vertebrate brains is basically the same. At the same time, during the course of evolution, the vertebrate brain has undergone changes, and become more effective. In so-called 'lower' animals, most or all of the brain structure is inherited, and therefore their behaviour is mostly instinctive. In mammals, and especially in man, the brain is developed further during life by learning. This has the benefit of helping them fit better into their environment. The capacity to learn is seen best in the cerebral cortex.