Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

Formation of conditioned reflexes and other types of learning provide animals with good behavioral plasticity. They enable each individual of the given species to adapt to the particular local conditions, which can differ from the long-term conditions under which the majority of this kind lives. The individual can even adjust its behavior to stimuli it never experienced before. If an adaptation to a unique lifetime situation is to be created (e.g. the need to recognize its parents), learning may occur in the form of imprinting. If the individual encounters the appropriate stimulus at a given moment, e.g. when a freshly hatched young goose meets a colored ball or Professor Konrad Lorenz, it will imprint the particular object into its memory as its mother and for the rest of its life this stimulus will remain a trigger for particular behavioral patterns. Behavioral patterns created by imprinting are long-term or permanent and do not need strengthening to last. On the other hand, once they are created they are usually irreversible; they can not be changed when the external conditions change. In contrast, standard learned patterns can disappear more or less rapidly. To last, they need to be strengthened continuously by a repeatedly occurring combination of the stimuli that produced the patterns. In a changeable environment, this is advantageous because reflexes that are no longer useful for the organism can give way to new ones. Conversely, imprinting is useful for stimuli that will probably not change during the individual’s life, e.g. recognizing its mother or members of its own species.