Behavioral Genetics and Animal Science - Genetics and the Behavior of Domestic Animals - page 12

suppressed during the early stages of training and sometimes for long into
the training, but as training progressed, instinctive food-getting behaviors
gradually replaced the conditioned behavior. The animals were unable to over-
ride their instincts and thus a conflict between conditioned and instinctive
behaviors occurred.
ETHOLOGY
While Skinner and his fellow Americans were refining the principles of
operant conditioning on thousands of rats and mice, ethology was being
developed in Europe. Ethology is the study of animal behavior in natural
environments. The primary concern of ethologists is instinctive or innate
behavior ( Eibl-Eibesfeldt and Kramer, 1958 ). Essentially, ethologists believed
that the secrets to behavior are found in the animal's genes, and the way genes
were modified during evolution to deal with particular environments. The
ethological trend originated with Whitman (1898) , who regarded behavioral
reactions to be so constant and characteristic for each species that, like morpho-
logical structures, they may be of taxonomic significance. A similar opinion
was held by Heinroth (1918, 1938) . He trained newly hatched fledglings in iso-
lation from adults of their own species and discovered that instinctive move-
ments, such as preening, shaking, and scratching, were performed by young
birds without observing other birds.
Understanding the mechanisms and programming of innate behavioral
patterns and the motivation underlying behavior is the primary focus of etholo-
gists. Konrad Lorenz (1939, 1965, 1981) and Niko Tinbergen (1948, 1951)
catalogued the behavior of many animals in natural environments. Together
they developed the ethogram. An ethogram is a complete listing of the beha-
viors an animal performs in its natural environment. The ethogram includes
both innate and learned behaviors.
An interesting contribution to ethology came from studies on egg-rolling
behavior in the graylag goose ( Lorenz, 1965, 1981 ). When a brooding goose
notices an egg outside her nest, Lorenz observed that an instinctive program
triggers the goose to retrieve it. The goose fixates on the egg, rises to extend
her neck and bill out over it, then gently rolls it back to the nest. This behavior is
performed in a highly mechanical way. If the egg is removed as the goose begins
to extend her neck, she still completes the pattern of rolling the nonexistent egg
back to the nest. Lorenz (1939) and Tinbergen (1948) termed this a “fixed action
pattern.” Remarkably, Tinbergen also discovered that brooding geese can be
stimulated to perform egg rolling on such items as beer cans and baseballs.
The fixed action pattern of rolling the egg back to the nest can be triggered by
anything outside the nest that even marginally resembles an egg. Tinbergen
realized that geese possess a genetic-releasing mechanism for this fixed action
pattern. Lorenz and Tinbergen called the object that triggers the release of a
fixed action pattern “sign stimuli.” When a mother bird sees the gaping mouth