Comparative Psychology, taken in its most usual, broad sense, refers to the study of the behavior and mental life of animals other than human beings. It is synonymous with animal psychology, but although the latter would be a more accurate term, it is less often used. Veterinarians sometimes use the phrase "animal psychology" to refer specifically to the study of disordered behaviour in animals, discussed below.
Comparative Psychology and the Comparative Method
Strictly speaking, comparative psychology ought to involve the use of a comparative method, in which similar studies are carried out on animals of different species, and the results interpreted in terms of their different phylogenetic or ecological backgrounds. Throughout the long history of comparative psychology, repeated attempts have been made to enforce this more disciplined approach, especially since the rise of ethology in the mid twentieth century. Behavioral ecology in the 1970s gave a more solid base of knowledge against which a true comparative psychology could develop. However, the broader use of the term "comparative psychology" is enshrined in the names of learned societies and academic journals, not to mention in the minds of psychologists of other specialisms, so it is never likely to disappear completely.
A persistent question with which comparative psychologists have been faced is the relative intelligence of different species of animal. Much effort has gone into explaining that this may not be a good question, but it will not go away. Indeed, some early attempts at a genuinely comparative psychology involved evaluating how well animals of different species could learn different tasks. These attempts foundered; in retrospect it can be seen that they were not sufficiently sophisticated, either their analysis of the demands of different tasks, or in their choice of species to compare. More recent comparative work has been more successful, partly because it has drawn upon studies in ethology and behavioral ecology to make informed choices of species and tasks to compare. Application of modern phylogenetic comparative methods has also helped to improve the rigor of statistical analyses and evolutionary inferences.Comparative Neuropsychology refers to an approach used for understanding human brain functions. It involves the direct evaluation of clinical neurological populations by employing experimental methods originally developed for use with nonhuman animals.
Over many decades of animal research, methods were perfected to study the effects of well-defined brain lesions on specific behaviors, and later the tasks were modified for human use. Generally the modifications involve changing the reward from food to money, but standard administration of the tasks in humans still involves minimal instructions, thus necessitating a degree of procedural learning in human and nonhuman animals alike.
Currently, comparative neuropsychology is used with neurological patients to link specific deficits with localized areas of the brain.
The comparative neuropsychological approach employs simple tasks that can be mastered without relying upon language skills. Precisely because these simple paradigms do not require linguistic strategies for solution, they are especially useful for working with patients whose language skills are compromised, or whose cognitive skills may be minimal.
Comparative neuropsychology contrasts with the traditional approach of using tasks that rely upon linguistic skills, and that were designed to study human cognition. Because important ambiguities about its heuristic value had not been addressed empirically, only recently has comparative neuropsychology become popular for implementation with brain-damaged patients.
Within the past decade, comparative neuropsychology has had prevalent use as a framework for comparing and contrasting the performances of disparate neurobehavioral populations on similar tasks.
Differences and similarities with comparative psychology.
Comparative psychology also studies animal behavior, but, as opposed to ethology, construes its study as a branch of psychology rather than as one of biology. Thus, where comparative psychology sees the study of animal behavior in the context of what is known about human psychology, ethology sees the study of animal behavior in the context of what is known about animal anatomy, physiology, neurobiology, and phylogenetic history. Furthermore, early comparative psychologists concentrated on the study of learning and tended to look at behavior in artificial situations, whereas early ethologists concentrated on behavior in natural situations, tending to describe it as instinctive. The two approaches are complementary rather than competitive, but they do lead to different perspectives and sometimes to conflicts of opinion about matters of substance. In addition, for most of the twentieth century, comparative psychology developed most strongly in North America, while ethology was stronger in Europe, and this led to different emphases as well as somewhat differing philosophical underpinnings in the two disciplines. A practical difference is that early comparative psychologists concentrated on gaining extensive knowledge of the behavior of very few species, while ethologists were more interested in gaining knowledge of behavior in a wide range of species in order to be able to make principled comparisons across taxonomic groups. Ethologists have made much more use of a truly comparative method than comparative psychologists ever have. Despite the historical divergence, most ethologists (as opposed to behavioural ecologists), at least in North America, teach in psychology departments.