来源：《新科学家》
原文刊登日期：2022年3月16日
Brain scanning studies that use magnetic resonance imaging (MRI) machines are often said to show links between the brain’s structure or patterns of activity and complex traits such as depression and certain aspects of personality. But for years, there have been suspicions that some of the headline-grabbing results aren’t trustworthy. Now, that has been confirmed.
使用磁共振成像（MRI）设备进行的脑部扫描研究通常被认为显示了大脑结构或活动模式与复杂特征之间的联系，如抑郁症和人格的某些方面。但多年来，一直有人怀疑，一些引人注目的研究结果并不可信。现在，这种怀疑得到了证实。
Almost all such research so far has had too few participants to find reliable results, according to a study by Scott Marek at Washington University in St. Louis and his colleagues. His group found that such studies need to look at the brains of thousands of people; they usually include an average of about 23 individuals.
圣路易斯华盛顿大学的斯科特·马雷克及其同事的一项研究表明，迄今为止，几乎所有此类研究的参与者都太少，无法找到可靠的结果。他的研究小组发现，此类研究需要观察数千人的大脑；而这类研究通常平均只包括23个人的数据。
Marek and his team analysed results from three of the largest ongoing neuroimaging studies to date, including the UK Biobank study, which had scanned nearly 36,000 participants at the time. They looked at links between brain structure or functioning and two relatively well-studied traits: cognitive ability and, in children, scores on “psychopathology.”
马雷克和他的团队分析了迄今为止最大的三项正在进行的神经影像学研究的结果，包括英国生物银行研究，该研究当时扫描了近36000名参与者。他们研究了大脑结构或功能与两个研究相对充分的特征之间的联系：认知能力和儿童的“精神病理学”得分。
By doing multiple analyses with varying numbers of people, they showed that when small sample sizes were used, they could find apparent correlations between these traits and the brain’s structure or function. But analyses of larger groups showed that these effects were either exaggerated or completely spurious. In some cases, different small samples could reach opposite conclusions, simply because people’s brains are so variable that random chance can sway the results one way or another.
通过对不同的人数进行多重分析，他们发现，当使用小样本时，他们可以发现这些特征与大脑结构或功能之间的明显相关性。但对更大群体的分析表明，这些影响要么被夸大，要么完全是错的。在某些情况下，不同的小样本可能会得出相反的结论，这仅仅是因为人们的大脑是如此多变，随机机会可能会以某种方式影响结果。
Although Marek’s team only looked at two traits, it is likely that its conclusion that these kinds of brain scanning studies need thousands of participants is true more broadly, says Kevin Mitchell at Trinity College Dublin.
都柏林圣三一学院的凯文·米切尔说，尽管马雷克的团队只研究了两种特征，但这类大脑扫描研究需要数千名受试者的结论可能在更广泛的范围内是正确的。
There is no reason to think that complex intellectual traits like people’s appetite for risk-taking or their political leanings will necessarily have any manifestation in brain tissues that would be visible on a scan, says Mitchell.
米切尔说，没有理由认为，复杂的智力特征，如人们冒险的欲望或他们的政治倾向，必然会在脑组织中有扫描可见的任何表现。
Results from previous small brain scanning studies of this type should now be viewed with suspicion. And unless it contains thousands of participants, the same goes for ongoing research.
以前这种小型脑部扫描研究的结果现在应该引起怀疑。除非它包含数千名受试者，否则正在进行的研究也应被怀疑。
The new analysis may lead to the MRI field having a kind of existential crisis, says Cassandra Gould van Praag at the University of Oxford. “There’s a bit of The Emperors’ New Clothes about this.”
牛津大学的卡桑德拉·古尔德·范·普拉格说，这项新的分析可能会导致核磁共振成像领域出现一种生存危机。“这件事有点像《皇帝的新衣》。”
The field of brain scanning needs a overhaul, with researchers committing to proper research practices before they get funding in future. Existing small studies could still be salvaged if multiple research teams band together to produce one large study, says Marek.
大脑扫描领域需要彻底改革，研究人员在未来获得资助之前必须承诺进行适当的研究实践。马雷克说，如果多个研究团队联合起来进行一项大型研究，现有的小型研究仍然可以挽救。