Rule Breaker

When it comes to morality, the philosopher Patricia Churchland refuses to stand on principle

Excerpt:    Oxytocin's primary purpose appears to be in solidifying the bond between

 mother and infant, but Churchland argues—drawing on the work of biologists—that

 there are significant spillover effects: Bonds of empathy lubricated by oxytocin 

expand to include, first, more distant kin and then other members of one's in-group.

 (Another neurochemical, aregenine vasopressin, plays a related role, as do 

endogenous opiates, which reinforce the appeal of cooperation by making it feel good.)

From there, culture and society begin to make their presence felt, shaping larger moral systems: tit-for-tat retaliation helps keep freeloaders and abusers of empathic understanding in line. Adults pass along the rules for acceptable behavior—which is not to say "just" behavior, in any transcendent sense—to their children. Institutional structures arise to enforce norms among strangers within a culture, who can't be expected to automatically trust each other.

Sandy Huffaker for The Chronicle Review

The Biology of Ethics 1

These rules and institutions, crucially, will vary from place to place, and over time. "Some cultures accept infanticide for the disabled or unwanted," she writes, without judgment. "Others consider it morally abhorrent; some consider a mouthful of the killed enemy's flesh a requirement for a courageous warrior, others consider it barbaric."

Hers is a bottom-up, biological story, but, in her telling, it also has implications for ethical theory. Morality turns out to be not a quest for overarching principles but rather a process and practice not very different from negotiating our way through day-to-day social life. Brain scans, she points out, show little to no difference between how the brain works when solving social problems and how it works when solving ethical dilemmas....

Recognizing our continuity with a specific species of animal was a turning point in her thinking about morality, in recognizing that it could be tied to the hard and fast. "It all changed when I learned about the prairie voles," she says—surely not a phrase John Rawls ever uttered.

She told the story at the natural-history museum, in late March. Montane voles and prairie voles are so similar "that naifs like me can't tell them apart," she told a standing-room-only audience (younger and hipper than the museum's usual patrons—the word "neuroscience" these days is like catnip). But prairie voles mate for life, and montane voles do not. Among prairie voles, the males not only share parenting duties, they will even lick and nurture pups that aren't their own. By contrast, male montane voles do not actively parent even their own offspring. What accounts for the difference? Researchers have found that the prairie voles, the sociable ones, have greater numbers of oxytocin receptors in certain regions of the brain. (And prairie voles that have had their oxytocin receptors blocked will not pair-bond.)...

The biologist Sue Carter, now at the University of Illinois at Chicago, did some of the seminal work on voles, but oxytocin research on humans is now extensive as well. In a study of subjects playing a lab-based cooperative game in which the greatest benefits to two players would come if the first (the "investor") gave a significant amount of money to the second (the "trustee"), subjects who had oxytocin sprayed into their noses donated more than twice as often as a control group, giving nearly one-fifth percent more each time....