—By David Pacchioli
Through most of human history, our morality—the capacity to perceive interests beyond our own, and to act fairly, caringly, even selflessly—has been touted as what defines us, separates us from the beasts. From Plato on, this moral dimension has been ascribed to our powers of reason, seated in the brain and holding tight rein on the passions below.
The rise of cognitive psychology in the 1960s, with its emphasis on brain as computer, tended to reinforce this rationalist view. A parallel development, however, developed in part as a reaction to the cognitive approach: the theory of multiple intelligences.
"Multiple intelligences is the idea that the measured IQ is really a very narrow view of human capability," says Paul Eslinger, professor of neurology at Penn State's Hershey Medical Center. "The human brain and potential is not just what we're able to think but what we're able to feel, and how we're able to integrate these two streams of experience and knowledge."
Of particular interest to brain researchers were the so-called moral emotions, distinct from such basic emotions as happiness or fear, Eslinger says, in that they are tied to the welfare of others, and of society at large. Empathy, guilt, gratitude, and disgust are examples of emotions that are intrinsically moral. Eslinger calls them "social" emotions, and in fact their social aspect is now thought to have been the driving factor in the evolution of the human brain.
"Drives such as reciprocal interaction, dominance, protection of family—certain basic processes that underlie not only survival of oneself but survival of a greater unit, of progeny—these exist in non-human primates, in a variety of species," Eslinger explains. "But in humans these drives have undergone a tremendous elaboration and are embedded within complex social contexts. We think it goes along with the front part of the brain, the prefrontal cortex, being vastly enlarged."
This enlargement, in turn, "has provided the basis for all of our interpersonal abilities," he says. "For language, for social groupings, for long-term relationships, even for things such as altruism. In working through a lot of the literature, from psychology and animal behavior as well as the clinical, it appears that we humans have these specialized processing modules that provide the basis for moral behavior—in other words, that there is a biological basis to morality."
A spike through the head
Phineas Gage's skull and life maskCredit Warren Anatomical Museum, Francis A. Countway Library of Medicine
Until recently, the only way for neurologists to test this theory was to carve up the brains of those deemed morally deficient—dead criminals, mostly—and compare them to "normal" brains, similarly defunct. That or study the behavior of patients living with a rare variety of brain damage.
The most famous case of the latter remains that of Phineas Gage, a railroad laborer in Vermont who, one day in the fall of 1848, suffered a horrific on-the-job injury. Gage, the foreman of a crew laying track outside the town of Cavendish, was tamping black powder into a hole drilled in rock when he apparently struck a spark. In a flash of explosion, the tamping iron, a three-and-a-half-foot-long bar an inch in diameter, blew through his left cheek and clean out the top of his head, landing some 30 yards behind him. "It essentially severed the front third of his brain," Eslinger says. "The surgeon who came to the scene described that he insert a could finger through either side of the wound and actually touch them. It was just this clean hole."
Amazingly, Gage survived, and was in fact strong enough to resume work in less than a year. His basic mental faculties—motor skills, memory, speech—were essentially intact. What had changed, profoundly and irrevocably, was his personality. Where before the accident, Gage had been regarded as an excellent foreman, thoughtful, shrewd with money, and well-spoken, afterward he was described as "fitful, irreverent, and grossly profane," and acting with little regard for others. His friends said he was "no longer Gage."
Over the past 20 years, Eslinger and others have looked into a number of cases involving trauma or stroke and resulting in similar changes in personality: "acquired sociopathy," in today's clinical terms. "One of the key changes seems to be a loss of ability to share and understand the experience of others," Eslinger says. In most of these cases, as in Gage's, the damaged area was the prefrontal cortex.