Hardwired Behavior; What Neuroscience Reveals About Morality
By Molinari, Gaeton
TANCREDI, Laurence. Hardwired Behavior; What Neuroscience Reveals about Morality. New York: Cambridge University Press, 2005. 240 pp. Cloth, $28.99-Tancredi sets out in his own words to “examine the history of our general idea about morality, and its development through childhood; show how modern neuroscience research is shifting the focus to the brain as a physical organ shaping moral responses; and illustrate the outcome of defective brain wiring in the development of undesirable moral traits.” In a final chapter, he paints a fantastic picture of a society one hundred years from now in which, based on a change in paradigm from “mentalism” (that is, the mind as something invisible and intangible) to “physicalism” (that is, the brain as the source of moral behavior), the potential for political control to create a homogenized moral society will once again, he fears, rear its Orwellian head. Many neuroscientists who started out with the brain as the target of their curiosity, interest, research, and practice now see colleagues in psychology and psychiatry add the prefix “neuro-” to their areas of specialty and subspecialties.
Indeed, the modern neurosciences, particularly those of chemistry, genetics, neurotransmission, and neuroimaging, have contributed massively to our understanding of brain formation, maturation, function, injury and to a lesser extent, recovery after injury. Tancredi finds a recent adaptation of MRI imaging-the functional MRI (fMRI)-of particular interest and, apparently, of particular credibility. Autoregulation is the process by which the brain not only commands (demands and gets) a constant flow of blood, in both volume and velocity, across a wide spectrum of systemic blood pressures but also that within that constant supply to the entire organ, when measured within the brain, there is enough surplus to permit the shifting of blood from less active areas to areas where more metabolic substrate is required to sustain the demand created by more active regions. The brain actually regulates its own supply of nutrients in response to its own needs. The fMRI is a technique whereby minute increases in blood flow to tiny areas of the brain, corresponding to the known general locations of specific nuclei, may be interpreted as increased neuronal activity of those nuclei. Similarly, with decreased flow, the reverse is thought to be true.
It has long since been established, however, that in pathological conditions, such as partial seizures in which one part of the brain is actually convulsing and in strokes in which part of the brain is actually “dead,” the mechanism of autoregulation itself is often suspended or dysfunctional.
Most studies using fMRI are based on anecdotal case reports and/ or small-sample-sized case series reports. Nonetheless, this technique and the numerous references made to published studies are a real asset to empiricists who are not concerned with the classical methods of neuron-epistemology, and to non-scientists who are only marginally exposed to them. And so far, so good. There have not been any newly imaged centers of function that had not been known by classical neuro-investigative methods.
Tancredi also briefly describes two other processes of abiding interest to the neurobiologist, namely, selective myelinization and dendritic sprouting, both anatomical indicators of primary or recuperative learning. In contrast to the sequence in which the subjects are taught in medical school-that is, anatomy first, then physiology – in most biological and engineering systems, function determines structure. Most who studied a generation ago were taught that the nerve fibers with the thickest myelin sheaths conduct the fastest. During the period of rapid brain growth and development, the increase in brain size from that of a small fist at birth to ninety-five percent of adult size when a person starts school in first grade is due to the deposition of the fatty substance myelin around the fibers connecting nerve cells already present at birth. If myelin were distributed first to the most frequently stimulated fibers, then the most frequently used pathways would become facilitated, (a pretty scary notion when you realize that most myelin is deployed before we even start formal education.) Those fibers that we avoid stimulating throughout a lifetime-pain pathways, for example-have the thinnest myelin coats and conduct very slowly. It has been found that myelinization does continue into adult life, especially in higher brain centers.
Dendritic sprouting is a process where by the dendrites, the receiving fibers of nerve cells, attempt and often succeed at growing new connections with previously unconnected or recently disconnected nearby stimulator fibers (axons). These are two of the mechanisms invoked to account for learning and the limited but definite improvement often seen in brain function after injury. But so are all of the scientific processes cited in this well- referenced book; they reveal purported mechanisms by which human behavior may occur or indeed be monitored. They ignore the possibility that there may be a mind, a spiritual component, or an immaterial soul. To the contrary, they are only helpful in explaining how the concrete brain works in support of the “abstract” but neither prove nor disprove the existence of the mind.
For most of the major issues he outlines, Tancredi seems nonjudgmental. He does speculate, however, that perhaps social order and morality exist only because of how the human brain is wired (the product of both nature and nurture). It must be said that the use of modern scientific tools to explain the various phenomena of brain function hardly justifies such a conclusion.
Even in a prophetic and horrific last chapter, Tancredi presents both sides of the issue of legislation to regulate the treatment of criminals, who presumably are compelled to their antisocial behavior because of how their brains are wired, but this reader cannot tell which outcome of the proposed legislation he supports. Tancredi is a forensic psychiatrist, a physician-attorney, and a clinical professor of psychiatry at New York University, and has been consulted in dozens of cases involving a wide variety of psychiatric issues.
This book may be recommended to the readers of this journal, philosophers who are interested in what some neuroscientists view as the possible outcome of their research. – Gaeton Molinari, M.D., George Washington University School of Medicine and Health Care Sciences, Emeritus.
Gaeton Molinari, M.D., George Washington University School of Medicine and Health Care Sciences, Emeritus.
Copyright Review of Metaphysics Mar 2007
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