Traders’ brains交易人员的大脑
作者: 0o。 / 4168次阅读 时间: 2011年9月30日
来源: 经济学人中文网
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Traders’ brains交易人员的大脑
Rogue hormones凶猛的激素

Bad trade? Blame the adrenal cortex
贸易萧条?归罪于肾上腺皮质
Sep 24th 2011

新闻背景

交易员违规致瑞银损失20亿美元瑞银集团(UBS)9月15日表示,旗下投行部门一名交易员未经批准违规交易,导致约20亿美元损失。分析师表示,上述损失似乎在可控制的范围之内。但外界怀疑,瑞银集团首席执行官格鲁贝尔(如图)能否让其重新站稳脚步。该行此前在信贷危机中蒙受重大损失,还爆出协助美国富人逃税的丑闻。


IF THE losses at UBS that surfaced this month were caused by a “rogue” trader, would that make his colleagues stable? Not if research being undertaken by John Coates, a neuroscientist at Cambridge University and a former derivatives trader, is anything to go by. His work suggests that hormones drive investment decisions to a far greater extent than economists or bank executives realise. When traders are on a winning streak, their testosterone levels surge, sparking such euphoria that they underestimate risk. When they are acutely stressed, the adrenal cortex produces a flood of cortisol, a hormone that can make them overly fearful and risk-averse.

如果瑞士联合银行本月出现的损失是由一位“凶猛”交易员引起的,这样的情形是否能使得他同事心安呢?”要不是剑桥大学神经系统科学家,前任衍生工具交易员约翰科茨对此研究,一切都不会有什么进展。他的研究结果表明荷尔蒙相比于经济学家或银行主管的认知更大程度上主宰着投资决策。当交易员连续成功交易时,他们的睾丸激素激增并兴奋起来,从而低估了风险。当他们面对突如其来的压力时,肾上腺皮质会产生大量皮质醇,这是一种让人过度害怕和潜意识躲避风险的激素。

Mr Coates says he was drawn to study these biochemical processes because he wanted to understand the “unbelievably powerful emotions” that make traders “go crazy”. In past experiments conducted on a London trading floor, Mr Coates saw cortisol levels in traders’ saliva jump by as much as 500% in a day. Remarkably, cortisol increased in direct correlation to implied volatility, a measure of expected future variance in asset prices. “The uncertainty is almost worse than the shock itself,” says Mr Coates. “It’s always a lot worse not knowing where the goddamn monster is.”

科茨先生说我之所以为这些生化过程吸引,是因为他想把这种使交易员疯狂的“不可思议的强大力量”弄明白。科茨先生说,过去在伦敦交易大厅进行过的实验,交易员唾液中的皮质醇含量在一天内增长500%。显然,皮质醇的增长与资产价格中的预期未来方差隐含波动率正相关。皮质醇的这种易变性比交易本身波动更难以琢磨,更糟糕的是不知道这怪东西在哪里,科茨先生说道。

Cortisol prepares humans for danger, partly by helping the brain retrieve important memories. This early-warning system is invaluable in the wild. But raging hormones can eventually wreck investors’ ability to think rationally. Chronic stress over weeks or months can produce so much cortisol that the brain focuses excessively on negative memories and perceives threats where they do not exist. This loss of judgment is exacerbated by other symptoms of stress, such as sleep deprivation.

皮质醇为人预知危险,确切的说应该是在一定程度上帮助大脑获取重要记忆。这种预先警报系统在自然环境下是无价的。但剽悍的荷尔蒙最终能摧毁投资者的理性思考能力。经历数周或数月慢性应激产生大量的皮质醇导致大脑负面记忆过度集中,又或感知到不存在的危险。也可以通过其他压力的症状使得决策判断失误增多,比如说睡眠不足。

Mr Coates likens this condition to the state of “learned helplessness” identified in the 1960s by Martin Seligman, a psychologist who delivered random electric shocks to dogs constrained in harnesses. Eventually the animals lost the will to escape, even once they could do so.

科茨先生把这种情况比作“习得性无助”,由马丁•塞利格曼在1960年定义的。马丁•塞利格曼是个心理学家,曾给困在马具上的狗做随机放电实验,先开始狗狗们都尽力挣脱,最终狗狗都失去了逃脱的意识。

Traders and rodents also seem to have something in common. Place a rat in an open field and its fear is obvious. Although visible symptoms of anxiety gradually disappear its cortisol levels remain elevated, showing that it is more stressed than it looks. Mr Coates has seen a similar phenomenon among traders. In questionnaires they displayed no awareness of the rampant stress indicated by their cortisol measurements.

交易人员和啮齿动物似乎也有一些共同点。把一个老鼠放在户外显眼的地方,显然老鼠是很害怕的。尽管表面上看见的焦急症状已消失,但皮质醇保持升高,这表明它比看起来的样子更紧张。科茨先生在交易员中发现了一个相似的现象,在调查问卷中他们故意表现出对压力的无意识,但皮质醇的测量数据出卖了他们。

One way to reduce the financial havoc these hormones might wreak could be for trading desks to hire more women. Women have about 10% as much testosterone as men, making them less prone to irrational exuberance. Competitive situations do not activate women’s cortisol response with such intensity, so market mayhem is less likely to impair their judgment. Call it a hormonal-diversification strategy.

交易部门雇佣更多的女性是一中减少这些荷尔蒙可能造成的金融灾难的方法。女性身体中的皮质醇只有男性中的10%,这使得她们更不倾向于做出非理性亢奋。女性的皮质醇响应没那么强烈不会形成竞争态势,所以市场混乱不太可能削弱她们的判断力。我们称这个为激素多样化战略。

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