Images that purport to show — in living color — the parts of the brain that generate such virtues as compassion, fairness and wisdom are invading turf that was once reserved for philosophers, theologians and psychologists.
From morality to math, a revolution in "functional" magnetic resonance imaging (fMRI), which observes brain blood flow, is being used by researchers to pinpoint the pieces of the brain that people rely on to think and feel.
So, what's the problem?
"A lot of these claims are just crazy," says neurophysiologist Nikos Logothetis of Germany's Max Planck Institute for Biological Cybernetics. "There is a fundamental mismatch between what these images are showing and what cognitive scientists are claiming for these studies."
Here's a sampling of fMRI tests from recent news releases:
•University of Florida researchers asked 12 volunteers to have an fMRI while watching ads for Coca-Cola, Evian and Gatorade "to find out how people really feel about something."
•University of Wisconsin researchers reported that when 16 Tibetan monks meditated inside an fMRI machine, the images showed "brain circuits used to detect emotions and feelings were dramatically changed in subjects who had extensive experience practicing compassion meditation."
•Researchers at Emory University scanned the brains of Zen meditators in Atlanta and reported that experienced practitioners can clear their minds of distractions more clearly than novices.
•University of Illinois and California Institute of Technology researchers asked people who were having an fMRI to share or take away meals from hypothetical Ugandan orphans "to shed light on the underpinnings of moral decision-making."
Such endeavors make fMRI experts nervous, says bioengineering professor Kenneth Foster of the University of Pennsylvania.
"The relation between brain activity and the kinds of things that people want to use fMRI for — lie detection, detection of consumer preferences — is complex and indirect," Foster says. "At best it gives a crude indication of brain activity."
How the scans work
The biomedical community has embraced fMRI scanners. A search on the words "brain" and "fMRI" at the National Library of Medicine's online catalog returns about 82,000 studies, 4,600 of them published this year alone. The scans work by putting people into a strong magnetic field and then pulsing a second magnetic field into the scanner from a perpendicular direction.
In regular functional magnetic resonance scans, which are done to examine the muscles and organs of patients, the magnetic pulses subtly pull on water molecules in patients' organs, with different responses that can be mapped onto images and reveal everything from tumors to sprained ankles.
To produce brain images, the magnetic pulses are tuned to resonate with oxygen molecules in blood. Volunteers are given a task or asked questions, and the scanners show where oxygen-heavy blood flows are headed, causing certain parts of the brain to light up in fMRI images.
The assumption, Logothetis says, behind many studies that claim to have found a brain "center" for some activity, such as lying or feeling empathy, is that these areas of high blood flow are where the particular activity occurs in the brain that corresponds to the task at hand.
"But we can't know that," Logothetis says, noting the brain is laced with billions of interconnected nerves. "We are seeing something that may have 10 other explanations."
More caution is required the further brain images get from simple tasks, such as counting, and more into emotions or morals, some experts say. "All fMRI results should be seen as even more preliminary and in need of independent verification and replication than is usually the case in science," says Australian neuroethicist Neil Levy of the University of Melbourne by e-mail. "It is only rarely that we learn something interesting about the mind, rather than the brain, from fMRI."
Others, such as neuroscientist Michael Gazzaniga of the University of California-Santa Barbara, suggest that view is too pessimistic. "I think it is damn interesting that moral beliefs, for example, of one kind vs. another, reliably and reproducibly activate certain brain regions. Don't you?" says Gazzaniga, author of Human: The Science Behind What Makes Us Unique. "In the big picture, we are moving toward a brain-based theory of why we believe the things we do as humans."
Because fMRI delivers images as well as data about brain activity, the technology is particularly susceptible to over-interpretation, says philosopher Adina Roskies of Dartmouth University, who also is a neuroscientist. "People are so wowed by the pictures, they are both happy to buy anything and inclined to make it really simple," she says. News stories about brain imaging in particular, she suggests, fail to report the complexity of studies.
The solution is using the technology as background for psychological studies of human behavior, not the whole story, says Logothetis and others. "We have a lot to learn, and fMRI doesn't tell us everything," says neuroscientist Sian Beilock of the University of Chicago, whose lab studies athletes with both brain scans and behavioral tests. "When we put it all together, we'll have a very nice tool."