The Brain from Inside Out

by György Buzsáki

Mainstream psychiatry, like cognitive neuroscience, is also under the historical influence of the empiricist representational framework. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in the United States is another prominent example of how human-conceived terms are used in attempts to draw boundaries among mental disorders. It is the “James’s list” of psychiatry. Each new edition is an attempt to fix problems with the previous ones. According to the American Psychiatric Association, the “goal in developing DSM-5 is an evidence-based manual that is useful to clinicians in helping them accurately diagnose mental disorders.” This aim reflects a collective subconscious desire to reduce a high-dimensionality problem, such as a complex psychiatric condition, to a single word or phrase: the diagnosis. Dimensionality reduction in statistics and information theory refers to a mathematical process of reducing the large number of variables under consideration to extract a set of principal variables or features using methods such as principal component analysis or nonlinear dimensionality reduction.3 Of course, these methods can only be as good as the data we supply to them. A further problem is that “humans are incorrigibly inconsistent in making summary judgment of complex information,” as expressed succinctly by the economist Daniel Kahnemann.