杏吧原创

There鈥檚 much more to human behaviour than brain activity (Image: Alexander Tsiaras/SPL)

NO CREVICE of the human experience is safe. Our deepest fears and desires, our pasts and our futures 鈥� all have been revealed, and all in the form of colourful images that look like lava bubbling under the skull.

That, at least, is the popular conception of neuroscience 鈥� and it鈥檚 worth big money. The US and the European Union are throwing billions of dollars at two new projects to map the human brain. Yet there is also a growing anxiety that many of neuroscience鈥檚 findings don鈥檛 stand up to scrutiny. It鈥檚 not just sensational headlines reporting a , there are now serious concerns that some of the methods themselves are flawed.

The intrepid outsider needs expert guidance through this rocky terrain 鈥� and there鈥檚 no better place to start than Brainwashed by Sally Satel and Scott O. Lilienfeld. Satel, a practising psychiatrist, and Lilienfeld, a clinical psychologist, are terrific sherpas. They are clear-sighted, considered and forgiving of the novice鈥檚 ignorance.

Their first stop is the fMRI scan 鈥� a staple of much brain research. Worryingly, the statistical techniques used to construct the images sometimes create a mirage of activity where none should exist. They have a telling example: one research team watching a salmon in an fMRI scanner as images of human faces were flashed at it saw its brain spark into life in certain shots 鈥� even though it was dead.

鈥淎 team watching a salmon in an fMRI scanner saw its brain spark into life 鈥� even though it was dead鈥�

Such fishy results are troubling enough, but even legitimate scans can be problematic. As the authors point out, brain images should be used only alongside other kinds of evidence. But all too often they are given the final say on human behaviour. A common pitfall, assert Satel and Lilienfeld, is 鈥渘eurodeterminism鈥� 鈥� the idea that a murderer, say, had been cursed with a brain defect that destroyed their sense of morality.

But such an idea fails to acknowledge the possibility that thousands of other people may have a similar defect without nursing murderous intentions. Neurology is not destiny.

You can鈥檛 escape the fact that our brains are the product of our experience as much as they are the product of our genes. Like Dorian Gray鈥檚 portrait in the Oscar Wilde novel, the disruptions that appear in a brain scan may reflect a lifetime of brutality rather than revealing the underlying cause. Yet increasingly, defence lawyers ask to use these images as evidence for diminished responsibility.

Satel and Lilienfeld use the same precise reasoning to dispatch the science of addiction, neuromarketing and lie detection. In doing so, they chart much of the territory where neuroscience is influencing our society, although they don鈥檛 foray into more theoretical territory 鈥� the choppy waters of intelligence, consciousness and language.

For that excursion, you can turn to A Skeptic鈥檚 Guide to the Mind by Robert A. Burton. It is, Burton says, 鈥渂est read as a late-night meditation鈥�, which might explain his slightly circular thesis: that our innate irrationality, revealed by neuroscience, has itself led neuroscientists astray in their attempts to understand the mind. 鈥淎ny application of data to explain the mind will always be a personal vision, not a scientific fact,鈥� he says.

For the most part, his conclusions are spot on. It can be foolish, for instance, to pin down the mark of genius to the size of different brain regions, because a well-pruned, smaller network can sometimes be more efficient than a tangled mass of wiring.

But in other areas, I found Burton a little too curmudgeonly to do the science justice. For example, he takes aim at researchers鈥� ill-advised media quotes, rather than focusing on the substance of their work.

Consider the discovery of mirror neurons 鈥� brain cells believed to help us understand the intentions of others. Burton is sharp about the discoverers鈥� off-the-cuff claim that mirror neurons help us to 鈥渞ead minds鈥�. Of course, taken literally, the claim doesn鈥檛 make sense, because none of us can predict another鈥檚 motives accurately. But in the process, he also writes off the potential of mirror neurons to explain everyday empathy, when there are many reasons to think that they could help us to 鈥渇eel鈥� another鈥檚 pain or joy.

Indeed, the danger of such 鈥渘euroscepticism鈥� is that we may throw the baby out with the bathwater. Brain imaging is, after all, an infant technology, and neither book really acknowledges just how quickly it is developing. Now, there are new, finer-tuned scans that are less prone to error, and portable scanners that allow you to take a peek at the brain鈥檚 reactions in more natural settings.

The new billion-dollar projects will only accelerate the pace. Our secrets are safe for now 鈥� but for how much longer no one can say.

This article appeared in print under the headline 鈥淪top messing with my head!鈥�