Christine Gilles, age 16, of Concord, N.H., for his question:
WHAT IS COMPARATIVE PSYCHOLOGY?
Comparative psychology is the study of animals' intelligence, needs, sensory capacities and characteristic behavior.
Animals are studied in their natural environments and in special environments like laboratories and zoos. The natural environment is the most interesting because animals are equipped by nature to survive there.
Scientists study the psychology of animals for curiosity's sake and also for practical reasons. For example, information about the migration and spawning of salmon is not only interesting in itself, but is also good for economic reasons.
Experiments with animals provide information about humans under conditions in which human experiments are not practical. The brains of rats, as an example, can be stimulated with electrical currents passing through surgically embedded wires. This type of experiment has yielded much information about how the brain regulates basic drives such as hunger and thirst.
Experiments with rats have also provided a great deal of valuable information about the psychological effects of drugs.
Results of animal experiments can be applied to humans only when it can be assumed that experiments with human beings would yield the same results. Often, whether they would or not is uncertain. But the assumption that they would can be justified sometimes because of the structural resemblance between humans and the higher animals, and from similar results of experiments that (ITAL) can (UNITAL) be performed on both human beings and animals.
Comparative psychologists are particularly interested in the ability of animals to learn about their environments and discover new ways of dealing with them.
These scientists have discovered that an animal's intelligence is closely related to the structure of its brain. Environments change and some animals adjust more easily than others to these changes.
Some of the most penetrating insights into the behavior of animals have been achieved by making radical changes in their natural environments. For instance, by isolating baby chickens, it was discovered that they need social stimuli for normal development. Isolation prevented this development.
Some findings of comparative psychology, however, can't be applied to humans.
Jellyfish, for example, were found to be absolutely incapable of learning. The behavior of this animal is determined entirely by its inherited structure. If that behavior is not appropriate to the environment in which the jellyfish finds itself, the animal simply will not be able to survive.