Philosophy and Cognitive Neuropsychiatry

A number of decades ago, new ideas and methods from computer science led to a range of significant innovations in psychology (Gardner 1985). This “cognitive revolution” brought together disparate fields, including cognitive psychology and neuroscience, to form a new paradigm for the study of the mind. Philosophy played a crucial role in this effort (Goldman 1993); in particular, functionalism argued that mental states can be defined in terms of their causal roles within an information-processing system, irrespective of its underlying particular physical substrate, e.g., neurons or silicon (Block 1978).

During the past decade or so, with growing data from neuroscience and other areas, the term “cognitive neuroscience” has become increasingly common (Gazzaniga et al. 1998). Older digital serial constructs (the von Neumann computer) have been replaced by a focus on parallel distributed processing (connectionism), and new data from fields such as functional brain imaging have shed light on the psychobiology of a range of psychological phenomena. The challenge for philosophy is to embrace also this latest variation of the psychological sciences (Churchland 1986).

Pathology has played a crucial role in advancing basic anatomy and biochemistry, and in an analogous way, examplars from neuro-psychopathology may be crucially useful (for both psychologists and philosophers) in the new arenas of cognitive science and cognitive neuroscience. Although cognitive science did not focus primarily on psychopathology, a range of research has been done at an intersection that might be termed cognitive clinical science (Stein and Young 1992). Similarly, “cognitive neuropsychiatry” has grown in parallel with cognitive neuroscience (David and Halligan 1996; Stein and Ludik 1998).

The value of cognitive neuropsychiatry for philosophy is exemplified by Northoff’s article. Drawing on the cognitive neuropsychiatry of Parkinson’s and catatonia, Northoff reviews data indicating that, while both these conditions involve akinesia, they are characterized by differences in phenomenological experience, psychological deficits (executive vs. attention/visuospatial), brain function (motor loop vs orbitofrontal cortical loop), and brain physiology (dopaminergic dysfunction vs GABAergic dsyfunction). He argues then that all four of these perspectives are necessary for a full description of the brain-mind.

Several issues are raised by this interesting article and by similar work. I want to briefly mention four:

1) What are the implications of cognitive neuropsychiatry for a view of the relationship between body and mind? Crucial to Northoff’s paper is the observation that similar motor symptoms (akinesia) in Parkinson’s and in catatonia are mediated by different corresponding mental states. The four perspectives on these disorders, he argues, remain ontologically neutral with regard to the brain-mind. Then, in his discussion of various fallacies, he argues against various forms of reductionism and emphasizes that both monistic and dualistic models of the brain-mind relationship fail either by eliminating mental states from the brain or by reducing them to anatomical structures.

Certainly, the complexity of the brain-mind is confirmed by various studies in cognitive neuropsychiatry. Baxter and colleagues (1992), for example, found that obsessive-compulsive disorder (OCD) is characterized by increased caudate activity, but that after successful treatment with either medication or psychotherapy, there was a normalization of such activity. It is hard to explain such data using dualistic ideas of pineal interaction or monistic reductionism.

Nevertheless, Churchland (1986) has provided a radical argument that as neuroscience and psychology co-evolve, establishing points of reductive contact is more or less inevitable. These arguments are relevant here, insofar as she specifically rejects a focus on phenomenology or on intentionality as sufficient to prevent intratheoretic reductionism. However, the term reductionism involves a number of ambiguities (Bhaskar 1979); Churchland’s view (1986, 294) emphasizes explanation and notes that reductions involve corrections of those levels of description that supply the explananda. Her views may therefore not be wholly incompatible with those of Northoff, who does not appear to argue against the co-evolution of neuroscience and psychology.

In practice, many cognitive neuroscientists and neuropsychiatrists are interested both in describing and explaining psychological states in psychological terms rather than simply in neurobiological ones (Andreasen et al. 1997). In other words, perhaps, they rely on an emergent materialism that states that while higher-order entities are explained...