Ethological Theories of Conrad Lorenz In 1935, Konrad Lorenz proposed imprinting differed from true associative learning in several important ways. First, susceptibility to imprinting is confined to very limited period in bird's life, the critical period. Second, Lorenz argued that once developed, imprinting is irreversible. For instance, if a bird was imprinted to a bird of another species, later contact with its own species would not eliminate effects of early experience. Third, Lorenz viewed imprinting as …showed first 75 words of 1005 total…

…showed last 75 words of 1005 total…experiment, and handling of the animals is kept to a minimum. These investigations have shown that imprinting is neither rapid nor irreversible, and also not restricted to a critical period, as was claimed by Lorenz and his followers. It has been also discovered that imprinting occurs in other species, and that learning components are more important than previously thought (Hoffman, 1996). There is evidence that this cumulative process entails the release of endorphins in the brain.