In 2001, a research team led by Princeton philosophy graduate student Joshua Greene, now at Harvard, published a landmark article in Science providing evidence that moral decision-making relies on emotion rather than on pure reason. The group used functional Magnetic Resonance Imaging to scan subjects as they read about moral dilemmas and found that brain areas associated with emotion lit up when the more vexing scenarios were considered.
The use of fMRI for psychological investigation shows no sign of abating. Researchers in the Aug. 4 issue of Science found the way certain options are presented to subjects (the so-called “framing effect”) is associated with activity in the amygdala, a deep brain structure which is key to the processing of emotion. This is just one of numerous recent examples that lend support to Greene’s theory.
fMRI took over from computed tomography for psychiatric studies as well as for research into simple cognitive and motor activities. It expanded into the study of financial decision-making (neuroeconomics) and even, more dubiously, neuromarketing. Perhaps the most intriguing use of fMRI is for investigating the neural correlates of emotion and moral judgments.
The idea that morality is guided more by passion than by rationality goes back as far as the 18th century. British philosopher David Hume, notorious for pointing out that causality is unprovable, stated that moral judgments resemble esthetic ones and that moral knowledge is attained through sentiment, not reason.
This became the basis of the theory of emotivism in the early 20th century that basically says that ethical statements are reducible to emotional expressions. In short order, it was trashed by philosophers far and wide. A few academics, however, were never convinced by the criticism. One of them, Colin Wilks of the University of Newcastle in Australia, has recently resurrected the doctrine in his 2003 book Emotion, Truth and Meaning, arguing that it has been misunderstood and caricatured.
Wilks said the biggest problem with emotivism is “that it leaves very little for conventional philosophers to talk (about) because it shifts the focus of inquiry to psychology.”
A colleague of Greene’s, University of Virginia social psychologist Jonathan Haidt, has presented a “social intuitionist” model that harmonizes with the Greene’s fMRI work. In a 2001 study for Psychological Review, Haidt found that in a moral context, people rely on what they’ve learned from their society and culture to react emotionally to events. Only later, if it’s necessary, do they concoct a rational explanation for those automatic judgments.
The use of neuroimaging in psychology has been criticized as being scientifically unsound, with some like neuroscientists Rodolfo Llinas and W.R. Uttal likening it to phrenology, the 19th century pseudoscience that claimed to divine personality traits from skull bumps.
In his 2001 book The New Phrenology: The Limits of Localizing Cognitive Processes in the Brain, Uttal writes “although the brain is certainly differentiated, most high-level cognitive functions cannot be justifiably associated with localized brain regions (because) high-level cognitive processes are associated with widely distributed activity in many parts of the brain.”
He also expressed doubts about how we label the thought processes themselves. Social neuroscientist John Cacioppo reflected this skepticism in an October 2003 American Psychologist article, “Just Because You’re Imaging the Brain Doesn’t Mean You Can Stop Using Your Head.”
VCU Medical Center neuropsychologist David Hess said the research was trying.
“We are peering into a black box and attempting to draw conclusions. Tricky business at best,” he said. Hess conceded the moral dilemma study “has at least face validity.”
Greene said while there is some merit to such criticism-and he agrees that there has been a fair amount of regrettable hype-this merely reflects the lack of development of the science. He expressed optimism that its present crudity will be overcome.
“Part of what we’re doing now is just getting our bearings, developing a more detailed functional map of the brain. You can call all that ‘phrenology,’ but if it’s accurate… then it’s valuable.”
On his Web site, Greene concedes that he has an “ultimately political agenda.” He opines that such major social problems as war, terrorism and environmental destruction are “a product of well-intentioned people abiding by their respective common senses,” and that the solution is to learn to distrust moral common sense.
“This is largely because our social instincts were not designed for the modern world,” he said, “nor.were they designed to promote peace and happiness in the world for which they were designed, the world of our hunter-gatherer ancestors.”
Neuroimaging has made the emotivist case more persuasive, but as for the above speculation, evolutionary psychology is not without its problems. There are many, including our limited knowledge of the Pleistocene, the period in which early humans developed. An abundance of alternative hypotheses also explain the data.
Nonetheless, Greene’s social theory can probably hold up without appealing to that “updated” sociobiology for theoretical support. Regarding the charges of neo-phrenology, however, they’re unlikely to slow down the engine of what Brazilian neurologist Jorge Moll has called moral cognitive neuroscience. As Uttal said, his camp is up against the Zeitgeist.