Pubdate: Fri, 18 Mar 2005 Source: Wall Street Journal (US) Column: Science Journal Page: B1 Copyright: 2005 Dow Jones & Company, Inc. Contact: http://www.wsj.com/ Details: http://www.mapinc.org/media/487 Author: Sharon Begley Bookmark: http://www.mapinc.org/coke.htm (Cocaine) WHILE BRAIN IMAGING OFFERS NEW KNOWLEDGE, IT CAN BE AN ILLUSION There, right there, see that spot of blazing red in a cool blue sea of your cortex? That's your brain on drugs. Or, more specifically, that's the brain of a recovering cocaine addict, clean for months, who sees a mound of white powder. His brain responds with the same craving and anxiety -- marked by the red on the brain scan -- as when he was snorting every night, which is why addiction is so tenacious. And here, see how a chess grandmaster activates the region of the brain that stores memories, such as those of games he has played or studied? But in the brain of a neophyte the activity is over here, in a region that analyzes positions from scratch. If you're impressed, you're not alone. Brain scans such as these have a power to persuade that other forms of data lack. Although measurements of recovering addicts' heart rates and skin properties (perspiration, basically) had already shown that seeing cocaine triggers an intense physiological reaction, and although grandmasters can tell you they memorize old game positions and strategies, in both cases the brain scans carried the day. They convinced policy makers that addiction reflects biology (rather than a character flaw), and laypeople that experts think differently from novices. Blame it on the cognitive paparazzi. Neuroimaging such as PET and fMRI are seducing laypeople and scientists alike into believing we know more than we do about how and why we think, feel and behave, some scientists say. The power of brain imaging, says Frank Keil, a Yale University psychology professor, reflects "the illusion of explanatory depth. If people see something, they are often deluded into thinking they understand it better than they really do." That is especially so now that neuroimaging is expanding beyond "where does the brain do multiplication?" to complex social and moral behaviors. In a fit of physics envy, researchers in economics, political science and even philosophy are deciding that neuroimaging is just the thing to make them more scientific. Yet the results are less than groundbreaking. Social psychologists had shown that people hold both implicit and explicit attitudes about other races, for instance, attitudes that are often at odds, says Elizabeth Phelps of New York University. Then along came fMRI images showing that unconscious brain activity, in the anxiety-generating amygdala, indeed increases when people see the face of someone of a different race. "When we got the pictures that tied this to a neural system, it didn't advance the science of social attitudes all that much," she says. "But if you're saying something based on a brain scan, people believe it a lot more than when social psychologists say the same thing based on behavioral data." So it goes in political science, too. "If a study finds that the 'anger' part of the brain lights up when a Democrat watches a Republican ad more than when he watches a Democratic ad, have we learned anything?" asks Prof. Keil. Not scientifically. But with every such study, the public gets a new, and troubling, message. "The more we publish these things, the stronger the message that there is a brain excuse for everything," says Prof. Phelps. "That makes many people say it's beyond their control, when in fact just because it's in the brain doesn't mean it's any less controllable." Another danger of being seduced by the cognitive paparazzi is that pretty pictures showing where in the brain something occurs obscure the fact that "where" is usually less interesting and important than "how" or "why." For instance, psychotherapists have reported that therapy lifts patients' depression, or alleviates obsessive-compulsive disorder. Those claims were often dismissed as unscientific -- until brain images showed that activity in regions linked to those illnesses really did change following successful therapy. The discovery was hailed as explaining how psychotherapy works. But did it? "It doesn't answer the important question of how successful treatment changed brain activity," says Susan Fitzpatrick, vice president of the James S. McDonnell Foundation, which funds neuroscience. She helped organize a forum on neuroimaging last month for the American Association for the Advancement of Science. Sometimes, to be sure, finding "where" solves a longstanding mystery. These have been among neuroimaging's greatest hits. For instance, brain scans show that when people conjure up a mental image (picture a giraffe), the same neuronal apparatus in the visual circuits becomes active as when you see a giraffe in the flesh. There had long been a debate over whether seeing in the mind's eye is really seeing; it is. Neuroimaging also shows that memory isn't a single process centered in one brain structure, as was long believed. Instead, different regions form and retrieve different kinds of memories. For all its flaws, neuroimaging is here to stay. No self-respecting psych department can afford to forgo it. Of the dozen or so new faculty members recently hired by his department, says Phillip Shaver, chairman of psychology at the University of California, Davis, 10 use primarily neuroimaging. Economists, political scientists and sociologists are not far behind. As with all powerful tools, let the user beware. - --- MAP posted-by: Richard Lake