Using neurology patients to probe moral reasoning, the researchers for the first time drew a direct link between the neuroanatomy of emotion and moral judgment.This is really interesting stuff, but I think where some caution needs to be kept is in announcing that this is the "source of" morality. After all, I imagine that neuroscientists have or soon will have identified that part of the brain that registers color. If that part of the brain were injured or removed, someone might be reduced to seeing the world in shades of grey rather than in color, but this would not in turn mean that color is a creation of that part of the brain. Color would still exist, the person in question would simply be unable to discern color without outside aid.
Knock out certain brain cells with an aneurysm or a tumor, they discovered, and while everything else may appear normal, the ability to think straight about some issues of right and wrong has been permanently skewed. "It tells us there is some neurobiological basis for morality," said Harvard philosophy student Liane Young, who helped to conceive the experiment.
In particular, these people had injured an area that links emotion to cognition, located in the ventromedial prefrontal cortex several inches behind the brow. The experiment underscores the pivotal part played by unconscious empathy and emotion in guiding decisions. "When that influence is missing," said USC neuroscientist Antonio Damasio, "pure reason is set free."...
At the University of Iowa Hospital, the researchers singled out six middle-age men and women who had injured the same neural network in the prefrontal cortex. On neuropsychological tests, they seemed normal. They were healthy, intelligent, talkative, yet also unkempt, not so easily embarrassed or so likely to feel guilty, explained lead study scientist Michael Koenigs at the National Institutes of Health. They had lived with the brain damage for years but seemed unaware that anything about them had changed.
To analyze their moral abilities, Dr. Koenigs and his colleagues used a diagnostic probe as old as Socrates -- leading questions: To save yourself and others, would you throw someone out of a lifeboat? Would you push someone off a bridge, smother a crying baby, or kill a hostage?
All told, they considered 50 hypothetical moral dilemmas. Their responses were essentially identical to those of neurology patients who had different brain injuries and to healthy volunteers, except when a situation demanded they take one life to save others. For most, the thought of killing an innocent prompts a visceral revulsion, no matter how many other lives weigh in the balance. But if your prefrontal cortex has been impaired in the same small way by stroke or surgery, you would feel no such compunction in sacrificing one life for the good of all. The six patients certainly felt none. Any moral inhibition, whether learned or hereditary, had lost its influence.
Similarly, the part of the brain being discussed here sounds like it produces an instinctual revulsion against the idea of killing another human. This might in many cases help someone avoid an immoral action -- though in other cases it might make them reluctant to perform a moral but difficult action. (It is notoriously difficult to train soldiers to kill enemy combatants, even in a necessary, just war situation.)
However, because color can be defined in strictly physical terms (a wavelength between X and Y is "green") we are less prone to assume that discovering how it is detected is the same as finding its source.