1. Description of the obstacle

It is now time to acknowledge that the scientific specificity of physiological psychology separates it from the rest of psychology. Although some psychologists would like to overcome the differences and reunite the science of psychology, most of us realize that this goal is not only impossible but also undesirable. The old ideal of unified knowledge has long been abandoned in the practice of modern science (Bachelard 1934, Kuhn 1962, Refinetti 1983). Instead of a coherent, integrated body of knowledge, what we have today is a dispersion of sciences that are only partially related to each other (Refinetti 1989).

Once we accept the fact that physiological psychology is irreconcilably separated from at least some of the remaining forms of psychological science, it is not difficult to realize that general psychology may be an epistemological obstacle to the advancement of physiological psychology. This was indirectly mentioned in Chapter 6, where the mentalist (or behaviorist) nature of some forms of psychology was described as an obstacle to physiological psychology. In the present Chapter, three new obstacles that emanate from psychology will be described, namely: bidimensionalism, innatism, and environmentalism.

Bidimensionalism refers to the idea that some phenomena are bidimensional, that is, have two distinct dimensions of being. This bidimensionality takes place in the temporal sphere (thus generating the past-present dichotomy) as well as in a topological sphere (thus generating the endogenous-exogenous dichotomy). Let's examine these concepts in a little more detail.

The endogenous-exogenous dichotomy refers to causal mechanisms as they relate to the organism, and is closely related to an obstacle previously studied (viz., psychophysical complementarism). A typical explanation in psychology indicates the fact that a strongly emotional event may lead to psychological distress and eventual neurotic symptoms. Although the neurotic symptoms may affect bodily functions (e.g., hysteric immobilization), they are determined by psychodynamic mechanisms. This means that an exogenous event (the emotional situation) is assimilated as an endogenous element in the physiology of the body and can affect the operation of several organs. For the behavioral neuroscientist (i.e., the physiological psychologist), organisms are topologically unidimensional. This means that, when a stimulus is presented to an organism, what "enters" the organism is not an image of the proximal stimulus but the nervous impulses generated at the sensory receptors. Inside the organism, everything has a single dimension: the neural dimension. Psychologists, as we just saw, often endorse the endogenous-exogenous dichotomy and argue that an exogenous stimulus can simply migrate into the organism. Thus, when the proximal stimulus is a "traumatic experience", the psychologist claims that this stimulus somehow enters the body and can lead to psychological disorders and mental illness. For the behavioral neuroscientist, a traumatic experience must have a neural correlate which enters the body as a series of action potentials. That is, the exogenous stimulus is always translated into endogenous activity. Consequently, when a psychologist shows that some form of mental illness results from a psychological conflict, he is not describing the etiology of the disease; rather, he is obstructing the study of what causes the disease.

In a similar way, the psychosomatic physician claims that a situation of psychological tension enters the body and eventually reaches the stomach to produce ulcers. For the neuroscientist, however, psychological tension is a condition of the central nervous system developed by a series of nervous inputs, and it is this condition of the nervous system that leads to nervous stimulation of the stomach to produce ulcers. As Le Grand noticed wisely, phenomena of a physical dimension and phenomena of a mental dimension cannot coexist inside the same organism (Le Grand 1974).

The temporal form of bidimensionalism is similar to the topological form. While making an analogy between the nervous system and a computer, G. C. Quarton described well the behavioral neuroscientist's view. According to him, past input and present input, as well as programming instructions, are codified together in one single language that controls the machine (Quarton 1967). That is, organisms are temporally unidimensional and have their past experiences incorporated in their nervous systems. On the other hand, psychologists often endorse the past-present dichotomy and claim that the past may come back to haunt a patient. For the psychologist, the remembrance of past incidents may unleash mental disorder. For the behavioral neuroscientist, the only way the past can haunt an organism is if the sensory inputs from the past episode were stored in the nervous system and can now be used to alter the current functioning of the brain.

Innatism, the second obstacle, is the opposite of the third obstacle, environmentalism. Needless to say, innatism is the conception that all important behavioral characteristics of an organism are genetically inherited and do not change appreciably as a result of experience. Environmentalism is the conception that all important behavioral characteristics of an organism are determined by experiencing the environment. Although many psychologists would defend one of these conceptions, behavioral neuroscientists believe that both innate disposition and environmental stimulation are essential for the causation of behavior (e.g., Hebb 1949, Kandel 1976, Piaget 1970). For the behavioral neuroscientist, the nature-nurture dichotomy is a fallacy.

2. Examples of the obstacles

Joseph Wortis (1967) provided us with a good example of bidimensionality when he described what he considers to be two types of mental retardation: the biological type and the non-biological type. The causes of non-biological retardation would be poverty, psycho-social deprivation, frustration, etc. Now, how can these factors affect the functioning of the brain? They certainly cannot cross the skull and attack neurons. If poverty, for instance, is a cause of mental retardation, it is not so as "poverty" but as damage to neurons and glial cells resulting from inadequate nutrition, lack of environmental stimulation, etc. Non-biological types of retardation cannot exist. To insist on their existence is to support the endogenous-exogenous dichotomy and, therefore, to obstruct the progress of behavioral neuroscience.

Innatism has traditionally been associated with ethology (e.g., Eibl-Eibesfeldt 1970, Ewer 1968). As Lorenz acknowledged, many ethologists believe that the machinery of behavior houses a considerable number of self-contained units that are refractory to learning (Lorenz 1966 [p.102]). More recently, the creation of sociobiology led to the development of even bolder innatist theories. For instance, Hamilton's (1975) claim that racial discrimination rests on direct genetic foundations is much more a reiteration of the innatist credo than an inference based on actual scientific research. It may be true that civil rights activists have repeatedly made unfounded claims in the opposite direction, but this is no excuse for a scientist to put scientific objectivity aside. Any form of radical innatism is obstructive, as it places an a priori principle above empirical research. No doubt we inherit innumerable characteristics from our parents. But many characteristics have to be learned, and it is only through investigation that we can know which ones have to be learned. To give only one example, research shows that infants are born with an equipotentiality for the perception of musical scales and that acculturation is responsible for the development of perceptual preferences (Lynch et al 1990).

Environmentalism has been traditionally associated with behaviorism. John Watson's (1925) claim that learning alone could determine whether any given child would become a successful business person or a beggar was as much a declaration of the environmentalist credo as an unfounded statement about the power of behavioral sciences. Skinner's (1972) claim that most behaviors are developed by operant conditioning is again only the reiteration of a credo. Orthodox behaviorists seemed to disregard the fact that the ability to learn is itself inherited.

Although not traditionally recognized as such, the culturalist school has also been a supporter of environmentalist beliefs. Cultural anthropologists, such as Ruth Benedict (1934), and sociologists, such as Emile Durkheim (1907) and Max Weber (1958), insisted on the importance of cultural (i.e., environmental) factors in the production of ordinary behaviors, new ideas, and economic policies. A recent example is Ruth Bleier's criticism of extreme innatism, where she defends an equally repugnant environmentalism: "Distinctions of human characteristics and temperaments into innate male and female natures have been social, cultural constructs and are not natural. They are part of an ideology that attempts to make what are in fact social and political distinctions appear to be natural and biological ..." (Bleier 1984 [p.7]). At the present state of our knowledge, Bleier's statement is just as unfounded as her opposer's. If anything, we would expect both an innate and an environmental component to exist. Statements that strongly favor either one of these components are espistemological obstacles to physiological psychology.

This Chapter has described bidimensionalism, innatism, and environmentalism as obstacles to the development of physiological psychology. Although this situation is claimed to result from a rupture between behavioral neuroscience and other areas of psychological research, it should be remembered that no claim of scientific superiority of behavioral neuroscience is being made. Even in cases where such a claim could be made (e.g., when the scientificity of behavioral neuroscience is contrasted with the uncertainty of parapsychology), it should not be forgotten that the universe of legitimate human intellectual activity is much broader than the domain of immediately- or ultimately-useful scientific research. Professor Michael Menaker, in whose laboratory at the University of Virginia I had the honor to work during the year of 1990, used to say that biological research is fundamentally an intellectual enterprise comparable to poetry, music, and visual arts. It would be mere hypocrisy to dismiss non-applicable scientific research as worthless research. It would be equally hypocritical to dismiss non-scientific activities as worthless activities.