性格测试到底靠不靠谱

    1908年，弗兰克•帕森斯在波士顿开设了世界上第一家职业指导中心。从一开始，他就询问潜在客户116个一针见血的问题，内容涉及他们的抱负、长处和弱点（以及他们多长时间洗一次澡）。但他当时还做了一件更加不寻常的事情——他测量了这些人的头骨。

    帕森斯是一位坚定的颅相学信徒。要是你的额头较大，他或许会建议你当律师或工程师。但如果你耳朵后的头骨比较发达，那么你就属于“动物型”，最适合从事体力劳动。

    令人欣慰的是，职业咨询自那时起已经取得了长足的进展。但现在，咨询师不再测量头脑的外形，而使用心理测试测量头脑内部已成为惯常做法。个性测试现已发展成为一大产业，是领导力和管理课程的标准程序，它不仅是求职面试流程的组成部分，而且日益成为职业辅导不可或缺的内容之一。但我们是否真的应该相信这类测试能够揭示出科学且客观的真相？

    我有一些坏消息要告诉你：即使最复杂的测试也存在很大的缺陷。以迈尔斯-布里格斯类型指标（Myers-Briggs Type Indicator，简称MBTI）为例。这种世界上最流行的心理测试的原理是荣格的性格类型理论，它每年大约被应用200多万次。MBTI测试通过二分法类别——比如你是一位性格内向者还是外向者，你的性情偏重于逻辑还是情绪（也就是它所称的“思维”和“感觉”）——来判定一个人属于16种性格类型的哪一种。

    关于MBTI测试有一个非常有趣，也有些令人担忧的事实。那就是，尽管这种测试非常流行，但30多年来，心理学家对它的批评从未终止过。一大问题是，它显示出了一种被统计学家称为低“重测可靠度”的现象。比如说，如果你仅隔5周，再接受一次这种测试的话，你被归入一个不同于首次测试的性格类别的几率大约在50％左右。

    第二种批评意见是，MBTI测试错误地假设一个人的性格归属于相互排斥的类别。你要么是一个性格外向者，要么是一个性格内向者，但绝非两者的某种混合。然而，大多数人恰恰介于两者之间。要是MBTI也测量高度的话，你要么被列入“高大”，要么被列入“矮小”，尽管大多数人的个头都在中等高度区间内。

    结果是，两个被标为“内向”和“外向”的人的测试分数可能几乎完全一样，但由于他们分处一条假想边界线的两侧，他们或许会被归入不同的性格类别。

    对于那些认为个性测试可以将他们引入一个完美职业生涯的人来说，还有一件事尤为重要。迈尔斯-布里格斯基金会欧洲独家经销商发布的文件显示，这项测试可以“让一个人深入了解自己可能会喜欢、并且能够获得成功的工作类别。”所以，如果你像我一样，被归为INTJ型（也就是说，你的主要性格特征是内向型，直觉感强，偏重于思维和判断），最适合你的工作包括管理顾问、IT专业人士和工程师。

    When Frank Parsons opened the world's first career guidance center in Boston in 1908, he began by asking prospective clients 116 penetrating questions about their ambitions, strengths, and weaknesses (and how often they bathed). But then he did something more unusual: He measured their skulls.

    Parsons was a committed believer in phrenology. If you had a large forehead, he might recommend you become a lawyer or engineer. But if your skull was more developed behind the ears, you were of the "animal type" and best suited to manual work.

    Career advice has, thankfully, come a long way since then. But now, instead of measuring the outside of people's heads, it has become common to measure the inside using psychometric tests. Personality testing has grown into a major industry and is standard procedure in leadership and management courses, as part of job-interview processes, and, increasingly, in career counselling. But should we really trust such tests to deliver scientific, objective truth?

    I have some bad news for you: Even the most sophisticated tests have considerable flaws. Take the Myers-Briggs Type Indicator (MBTI), the world's most popular psychometric test, which is based on Jung's theory of personality types. Over two million are administered every year. The MBTI places you in one of 16 personality types, based on dichotomous categories such as whether you are an introvert or an extrovert, or have a disposition towards being logical or emotional (what it calls "thinking" and "feeling").

    The interesting -- and somewhat alarming -- fact about the MBTI is that, despite its popularity, it has been subject to sustained criticism by professional psychologists for over three decades. One problem is that it displays what statisticians call low "test-retest reliability." So if you retake the test after only a five-week gap, there's around a 50% chance that you will fall into a different personality category compared to the first time you took the test.

    A second criticism is that the MBTI mistakenly assumes that personality falls into mutually exclusive categories. You are either an extrovert or an introvert, but never a mix of the two. Yet most people fall somewhere in the middle. If the MBTI also measured height, you would be classified as either tall or short, even though the majority of people are within a band of medium height.

    The consequence is that the scores of two people labelled "introvert" and "extrovert" may be almost exactly the same, but they could be placed into different categories since they fall on either side of an imaginary dividing line.

    One other thing, and this matters especially for anybody who thinks personality tests can guide them to a perfect career. According to official Myers-Briggs documents published by its exclusive European distributor, the test can "give you an insight into what kinds of work you might enjoy and be successful doing." So if you are, like me, classified as INTJ (your dominant traits are being introverted, intuitive, and having a preference for thinking and judging), the best-fit occupations include management consultant, IT professional, and engineer.