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Ask a biologist, "What is biology?" and you are likely to get a relatively unambiguous response. Biology is the science of life. In contrast ask a psychologist, "What is psychology?" and if the individual has considered the question in depth, you are likely to get something along the lines of the following: "It is basically the science of the mind, except for the fact that there still are a number of psychologists who think of it as the science of behavior, and argue that 'the mind' is not a helpful scientific construct. So you can call it the science of behavior and mental processes, but that glosses over the basic philosophical problems that initially pitted behaviorism against mentalism. It currently deals primarily with human behavior, although historically many psychologists studied animals, perhaps most notoriously the lab rat. And yet, the line between humans and other animals-if there is one at all-is not generally agreed upon. Some scholars believe that psychology is really a loose federation of subdisciplines and that as our scientific knowledge becomes more advanced it will break up into fields like neuroscience, cognitive science, linguistics, and other areas. And now there are quite a few psychologists, especially those studying culture and continental philosophy, who question whether natural or even social science epistemologies are appropriate. They argue that psychology is best thought of as a collection of studies and belongs as much with the humanities as the sciences. Finally, there is the issue of whether the discipline is mainly a science like biology or is mainly a healing profession like medicine, or is simultaneously both. Given all of this controversy, it is probably best just to think of psychology as an institution, a human construction that doesn't necessarily map directly onto nature. Rather than worry about definitions, we should spend our energy conducting studies on phenomena of interest." Such is the current state of our knowledge on the question of "What is psychology?"
If you have any doubts about the importance of effectively defining the discipline, I recommend the pointed essay, At War With Ourselves, by Cummings and O'Donohue (2008). They point how, for the first half of the 20th Century in America, psychology was dominated by behavioral experimentalists who were "obsessed with learning theory...with most of the so called discoveries deriving from rats and pigeons, not humans" (p. 118). The term 'clinical' was frowned upon, and even an applied emphasis was looked at by many with suspicion. Although psychoanalysis was in ascendancy in practice, it was off campus and still practiced mostly by psychiatrists. Reporting on his own training experience in the late 1940s and early 1950s, Cummings, who wanted to be a professional practitioner, stated that he...
experienced the shock of [his] life: Psychology did not have anything to do with people. Psychotherapy training was nonexistent, as was the very word itself. We got all our training in psychotherapy off campus...Had our graduate faculty learned of this, we would have been drummed out of the program.
Cummings and O'Donohue (2008) go on to recount the rise of professional practice and the ensuing battle for ownership over the discipline. They articulated the conflicts between scientists and practitioners regarding licensure and the professionalization of the discipline, the role of evidence and the scientific method in informing practice, and the way that practitioners became the more dominant force in the American Psychological Association, and how this ultimately resulted in many scientifically oriented psychologists leaving the association and forming the Association for Psychological Science. For me, additional evidence regarding the enormous confusion about psychology is seen in the fact that although psychologists in America were originally scientists experimenting with animals in the lab, with the rise of professional psychology, it has now evolved to the point where the only people that can legally call themselves psychologists are licensed practitioners. In most states, a social psychologist working at a university cannot legally refer to herself as a psychologist! Instead, she must identify herself as a professor of psychology. All of this shows just how much confusion there is regarding the nature and place of the discipline in society.
It does not have to be this way. The unified theory of psychology (UT) paves a way to logically and coherently define the field of psychology, resolve the longstanding philosophical problems, and weave together key insights from various paradigms into a coherent whole. So, according to the unified theory, what exactly is the definition of psychology?
Psychology is the science of mental behavior and the human mind, and the professional application of such knowledge toward the greater good.
How is this definition different than the normal definition of psychology as the science of behavior and mental processes? Its benefit is that resolves the three primary areas of controversy regarding what exactly psychology is, specifically, it resolves the problem of mind-behavior dualism, the animal-human problem, and the science versus profession problem.
First, defining psychology as the science of behavior and mental processes has some major ambiguities. Consider it this way. Atoms behave. Cells behave. If this is so, then psychology cannot be the science of behavior, but has to be the science of a particular type of behavior. Also, consider the question of what are mental processes if they are not behaviors? Skinner considered thoughts as internalized, covert behaviors and in that regard it is hard to argue with him. The UT posits that animal behaviors are a unique kind of behavior, depicted as the third dimension of complexity on the Tree of Knowledge System and labeled 'Mind". Mind consists of the set of mental behaviors, which are clearly defined as animal behaviors mediated by the nervous system that produce a functional effect on the animal environment relationship. Now, we can divide mental behaviors into two broad domains: 1) overt (changes between the animal and the environment) and 2) covert (changes within the nervous system). These two domains correspond to what is generally meant by 'behaviors' and 'mental processes', but puts them together in a clear, nondualistic way.
Second, the definition separates basic (animal) psychology from human psychology. John Watson famously declared there was no dividing line between man and brute. This justification legitimized the work of the behaviorists, but the UT (along with much observational data) argues that in fact humans are a very unique kind of animal. The UT claims that human behavior is defined by the functional intersection of language, culture, and self-consciousness (i.e., justification systems) and this makes studying humans a fundamentally different problem. Not only that, but because humans will use theories about them that scientists generate, human psychology is a social science and must contend with problems of value much more than basic psychology. Consider, for example, there would be little controversy if psychologist found one strain of rats learned to run mazes faster and more accurately than others. Now, think about the very legitimate controversies surrounding race and IQ and you will have a clear understanding of why the science of human psychology is fundamentally more intertwined with human values.
Third, the definition draws a much needed line between the science and the profession. That line is crucial to understand because the science has a fundamentally different mission than the profession. The goal of the science side of psychology is to describe and predict animal and human behavior. The goal of the profession is the advancement of human (and animal) well-being. Different goals lead to different competencies and different identities. Of course, science and application overlap and science should inform practice and vice versa (I was trained in the scientist-practitioner model), but they are conceptually separate and that separation should be made clear (think of physics and engineering, biology and medicine, sociology and social work...we should not have psychology and psychology).
Psychology has been around for well over a 100 years. Yet, it has never been effectively defined. I believe that with the UT we can remedy the age-old conceptual confusions and move the discipline into a much more coherent state of being.
