最新研究：睾丸激素与自闭症没有直接关系

一项重大的新研究，推翻了之前有争议的自闭症假说

A compelling new study has found no link between testosterone in men and reduced cognitive empathy, a trait that is characteristically impaired in autism spectrum disorders.

一项引人注目的新研究发现，男性体内的睾酮与认知同理能力下降之间没有联系，而认知同理心在自闭症谱系障碍中是典型的受损特征。

Ever since the very first clinical account of autism, almost eighty years ago, far more male children and adults have been placed on the spectrum than females. In all that time, no has been able to figure out why.

自从近80年前首次对自闭症进行临床研究以来，越来越多的男性儿童和成人被纳入自闭症研究范围。一直以来，没有人能找出原因。

Today, one of the most popular and commonly cited hypotheses is also one of the most controversial. First proposed by psychologist Simon Baron-Cohen, the 'extreme male brain' (EMB) hypothesis suggests high levels of prenatal hormones in the womb can lead to hyper-masculine traits later on, such as a reduced ability to read emotions in others.

如今，最流行和最常被引用的假设之一也是最具争议的假设之一。“极端男性大脑”(EMB)假说最早由心理学家西蒙•巴伦-科恩提出，该假说认为，子宫内的高水平产前激素会导致日后的男性特征过于男性化，比如解读他人情绪的能力下降。

Evidence for this theory is highly disputed on many different levels. Because it's too dangerous to manipulate prenatal testosterone in human subjects, most previous studies on the role of testosterone have relied on correlations only.

这一理论的证据在许多不同层面上都有很大争议。因为在人类受试者中控制产前睾酮太危险了，以前大多数关于睾酮作用的研究都只依赖于相关性。

Researchers have, for example, tested testosterone in adults and used digit ratios as a proxy for prenatal testosterone levels.

例如，研究人员对成年人进行了睾酮测试，并用手指比例作为产前睾酮水平的指标。

What's more, much of this research is small and inconsistently replicated. A study co-authored by Baron-Cohen in 2011, for instance, was only conducted among 16 young women. It found that when testosterone was administered to these participants, it reduced their performance on a test of reading others' emotions, called Reading the Mind in the Eyes Test (RMET).

更重要的是，这项研究的大部分都是小规模的，重复性不一致。例如，2011年由科恩男爵(baron cohen)合著的一项研究，只在16名年轻女性中进行。研究发现，当这些参与者服用睾酮时，他们在一项名为“眼睛读心术”(RMET)的测试中的表现会下降。

The study also found a link between the ratio of the second and fourth finger, known as the 2D:4D ratio, and a woman's sensitivity to testosterone - an idea that has turned up mixed results and is highly controversial as proxy for the prenatal environment.

这项研究还发现，第二和第四指的比例(称为2d:4d比例)与女性对睾丸激素的敏感度之间存在联系——这一观点出现了各种各样的结果，作为产前环境的代表，备受争议。

"People referred to that original study as if it was a solid stepping stone," Amos Nadler, a neuro-economist at the University of Toronto, told Science magazine.

多伦多大学(University of Toronto)神经经济学家纳德勒(Amos Nadler)在接受《科学》杂志采访时说：“人们把这项最初的研究称为坚实的垫脚石。”

"Pardon my French, but nobody was calling bullshit."

“请原谅我的法语，但没人说胡话。”

Delving deeper, Nadler and his colleagues conducted two randomised controlled studies with samples that were 15 and 25 times greater than the original 2011 study. They also decided to focus only on males, as males are roughly four times more likely to be diagnosed with autism.

深入研究，纳德勒和他的同事进行了两项随机对照研究，样本数量分别是2011年原始研究的15倍和25倍。他们还决定只关注男性，因为男性被诊断患有自闭症的可能性大约是女性的四倍。

Conducting one of the largest studies to date, the researchers administered testosterone or a placebo to 643 male participants. To avoid giving people the same test twice - a pitfall of previous research - the researchers split participants into two groups.

研究人员进行了迄今为止规模最大的研究之一，对643名男性参与者使用睾丸激素或安慰剂。为了避免让人们进行两次相同的测试——这是之前研究的一个陷阱——研究人员将参与者分成两组。

The first group, composed of 243 volunteers, had their testosterone levels measured for a baseline and then completed the first half of a cognitive empathy test, the same one that was used in the 2011 study. This group was then given a single dose of testosterone gel or a placebo on the shoulder and finished the rest of the test.

第一组由243名志愿者组成，测试他们的睾酮水平作为基线，然后完成认知移情测试的前半部分，与2011年研究中使用的相同。然后在肩膀上注射单剂量的睾丸酮凝胶或安慰剂，完成其余的测试。

The second group, composed of 400 people, undertook the same routine but this time with a nasal gel. The fingers of each participant in each group were also measured.

第二组，由400人组成，进行同样的程序，但这次使用的是鼻凝胶。还测量了每组参与者的手指。

"Our research shows that there is not a causal relationship between testosterone levels and the capacity to understand others' thoughts and feelings, which is a hallmark impairment of autism spectrum disorders," Nadler told ScienceAlert.

纳德勒在接受《科学警报》采访时说：“我们的研究表明，睾丸激素水平与理解他人想法和感受的能力之间没有因果关系，这是自闭症谱系障碍的一个标志性损害。”

The behavioural economist says the new results cast serious doubt on previous studies, suggesting that past conclusions were "underpowered and therefore unreliable". As such, he says they make poor evidence for the extreme male brain theory, and he suggests that the role of testosterone in cognitive empathy is much more complex than we often think.

这位行为经济学家表示，新的研究结果对之前的研究提出了严重质疑，表明过去的结论“力度不足，因此不可靠”。因此，他说，他们为极端的男性大脑理论提供了很差的证据，他认为睾丸激素在认知同理心中的作用比我们通常认为的要复杂得多。

"We found that there is no evidence to support this effect of testosterone, but that doesn't rule out any possible effects," says Gideon Nave, a marketing researcher at the University of Pennsylvania.

宾夕法尼亚大学的市场研究员吉迪恩·纳维说：“我们发现没有证据支持睾酮的这种作用，但这并不排除任何可能的影响。”

"From what we know, though, it seems that if testosterone does have an influence, the effect is complex, not linear. Reality is typically not that simple."

“不过，据我们所知，似乎如果睾丸激素确实有影响，这种影响是复杂的，而不是线性的。现实通常不是那么简单。”

The new findings are supported by other recent studies that have found no relationship between prenatal testosterone exposure and autistic traits.

这一新发现得到了最近其他研究的支持，这些研究发现产前睾酮暴露与自闭症特征之间没有关系。