Functional magnetic resonance imaging, or fMRI, is a technology barely 20 years old, but the pictures of brain activity it produces have already become iconic and changed the way we think about the mind. Many of us have seen news items trumpeting discoveries about how we respond to any number of stimuli, accompanied by scans indicating, through blobs of hot, bright color, which areas of the brain are activated when we see or think about things we find hateful, arousing, challenging or trustworthy.
There's just one problem: Researchers aren't really sure exactly what those scans are telling us. So none of us should be using them, at least not yet, as the sole basis for wide-reaching medical or policy prescriptions.
"It is very difficult for scientists to look at a fiery spot on a brain scan and conclude with certainty what is going on in the mind of the person," Scott Lilienfeld, Emory University professor of psychology, writes in Brainwashed: The Seductive Appeal of Mindless Neuroscience, the new book he co-authored with Sally Satel, psychiatrist and American Enterprise Institute for Public Policy Research resident scholar.
The Risks of Neurocentrism
"Because it's new, we should give the technology a bit of slack," Lilienfeld said in an interview with Next Avenue. "There's still a lot of potential to be realized. But that also means we need to be a bit modest and humble in our conclusions. We still have a lot to learn about what these images can and can't tell us. The concern is really not the technology itself but the overhyping."
Lilienfeld and Satel warn against the potential dangers of "neurocentrism," or the view that human behavior can be best explained by looking solely or primarily at the brain. "Some of the claims run ahead of where the data are," Lilienfeld says, "and we try to instill a note of caution."
One fundamental misconception in neurocentrism, he argues, is the idea that each area of the brain directly corresponds to one emotion or mode of thought. The reality is that most neural real estate is "zoned for mixed-use development," he says. We can identify areas of the brain that "light up" in response to different stimuli, but that's rarely the whole story. "The brain is very complicated and it would be remarkably inefficient if each area did one and only one thing," Lilienfeld says. "There's a whole lot of stuff packed within that three pounds in our skull. It's the most complex structure in the known universe. One reason it's complex is that different regions can perform different functions. If not, we wouldn't be as complex as we are.
"If you were a Martian who came to Earth and saw someone's legs move, you couldn't say that means X or Y. The legs could be moving because we're walking, running, kicking, bored or were just bitten by a bee. It could mean a thousand different things. The same is true in the brain, but the complexity is much greater.
"It's a mistake to say that because this brain area became activated, it must mean the person is experiencing psychological state X," Lilienfeld says. "It's rarely, if ever, possible to do that and sophisticated imagers know that. There are lots of very responsible neuroscientists out there, the majority, and they know that brain imaging is only one tool among many."
Unfortunately, others seeking to make a quick buck from fMRI technology are less responsible, Lilienfeld argues. His book details the follies of what he and Satel call neuromarketing and neuropolitics, in which vendors trumpet their ability to gauge a political candidate's potential success or a new product's future sales by reading the brain scans of volunteers exposed to images, speeches or demonstrations. "An entrepreneur will note that people show activations in response to certain stimuli," he says, "then claim they like or dislike a person or product. That's risky business."
In just one example from the book, the authors recount how, during the 2008 presidential primary season, a research firm claimed that fMRI scans proved which candidates swing voters responded to positively or negatively. The two who landed at the bottom of the list? The eventual nominees, Barack Obama and John McCain.
Psychology and Neuroimaging: Pros and Cons
In Lilienfeld's own field, he believes, "Neuroimaging provides us with valuable information and a different level of analysis on human behavior." Many psychologists, for example, rely on patients' answers to questionnaires and their self-reports to gauge their conditions, but those sources have obvious limits. Brain imaging can provide "converging evidence" that supports or confirms a potential diagnosis.
But relying on the technology too heavily has limitations as well, he says. Neuroimaging may help us identify some of the mechanisms of depression and other ailments, but the fact that we can see how conditions manifest in the brain, on a biological level, should not go hand-in-hand with the assumption that they have strictly biological causes or that they can only be treated with medication.
Whether our condition has an "environmental" cause we can identify, like the loss of a parent, or a biological cause we can spot on a scan, doesn't mean that either a psychological or a pharmaceutical intervention will necessarily work better, Lilienfeld says. "The cause of the condition doesn't bear any implications for its treatment and vice versa.
"Enormous sums of money have been poured into biological interventions for depression, to take one example," he says. "But we know from data that psychotherapy seems to be at least as effective as medication for depression and there's increasing evidence that it's more effective for preventing recurrence than medication. There's a fundamental misconception out there that because depression is a biological illness we need purely biological treatments for it.
"There's an understandable desire for a quick fix, to take a pill," he says. "Some psychological treatments take some work and effort, but there's increasing evidence that they are more effective in the long term."
What Comes Next
In the laboratory, neuroimaging has wide potential to increase our knowledge, Lilienfeld says. "It can tell investigators where to look next," he says, adding that as the field develops, so will its ability not just to identify areas of the brain that are activated at one moment or another but to determine how they connect and interact. "It's not merely which areas become activated, but which come first, second or third in a causal chain. Brain imaging might provide us with some clues to what comes first and perhaps what's causing what."
As the technology improves, he says, "Instead of looking at big blobs in the brain which encompass hundreds of thousands of neurons, we will get better and better at looking at activity at the level of brain cells where there's a lot more resolution and a lot more information about what's happening. We have very crude mapping right now. By understanding what's happening at the level of individual brain cells, we'll get better at looking at neuroconnectivity — and that will bring us a lot more information.
"When we find the cure to Alzheimer's disease," he says, "I'd be very surprised if brain imaging techniques don't play some role."