Criminal Behavior and the Ethics of Biological Intervention
Weyant, R. G., The Humanist
Humanity's long history of attempting to understand how the brain is structured and functions is a mixture of painstaking observations, brilliant insights, and spectacular errors. Knowledge in this area developed sporadically from antiquity through the eighteenth century, during which time it still had to compete with the notion that a nonmaterial mind-soul was the primary source of most human mental phenomena. This nonmaterial cause of human behavior, though it played a gradually decreasing role in the sixteenth and seventeenth centuries, still acted to preclude a complete understanding of the brain-behavior relationship.
The most dramatic increases in our neurological understanding came in the late twentieth century with the development of technologies that allowed researchers to view the activity of the human brain while the subject was awake and carrying out various actions. Furthermore, we have learned that during the first few years of life the basic brain material produced, in keeping with instructions from the genes, refashions itself and its connections according to what it encounters in its environment. During infancy, excess unused nerve cells die off and those that are frequently used develop networks with other cells.
This kind of information has led many scientists to accept as a working hypothesis the idea that human behavior is understandable as the product of the functioning of the human nervous system. The late Nobel prizewinning biologist Francis Crick put the idea this way in his 1994 book The Astonishing Hypothesis: The Scientific Search for the Soul:
The Astonishing Hypothesis is that "You," your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. ... The scientific belief is that our minds--the behavior of our brains--can be explained by the interaction of nerve cells (and other cells) and the molecules associated with them.
The cells that make up the brain are specialized to carry electrical impulses along their lengths and to release chemical neurotransmitters under particular circumstances. The neurotransmitters move between neurons at the synapses and are what cause neighboring neurons to become activated and carry impulses to other parts of the brain. There have been a number of different neurotransmitters identified and they each lead to fairly specific feelings and functions. For example, serotonin functions to modulate emotions and the biological drives that motivate behavior; in particular it provides positive feelings and keeps aggression under control. If too little serotonin is produced, aggressive behavior will develop. The drug Prozac is used to control levels of serotonin. On the other hand, another neurotransmitter, noradrenaline, acts to arouse the brain when danger threatens by producing adrenaline that leads to quicker reactions, increased heart rate, muscular stamina, and other conditions useful when either fight or flight is called for. Noradrenaline also affects mood and mental arousal. The neurotransmitter dopamine plays a role in arousal as well as the production of schizophrenia and hallucinations. These chemicals also result in our feelings of aggression and tear and are all part of Crick's astonishing hypothesis.
In this light, it follows that, if you can control the chemicals of the brain you can control feelings and behavior. This isn't to argue that scientists currently can explain all of the unquestionably complicated behavior of human beings in biochemical terms. However, as a working hypothesis there seems to be no reason why such explanations might not be achieved in the future and that some amazing progress appears to have been made in that direction. And the future may not be all that far away. In her 1999 book, The Biology of Violence: How Understanding the Brain, Behavior, and Environment Can Break the Vicious Circle of Aggression, Debra Niehoff extends Crick's astonishing hypothesis to take into account the finding that the genetically determined structure of the brain can be modified by experiences in the subject's environment:
Dreadful sights, angry voices, a racial slur, the feel of the trigger, as well as moderating influences--reason, memory, conscience--are not cultural or spiritual ephemera, but depend on the movement of molecules, the integrity of proteins. …