好男人与坏男人

來源：英国《金融时报》
作者：专栏作家提姆·哈福德(Tim Harford) 2009-09-18

亲爱的经济学家,

假设我们绘制一条我对男人的偏好曲线，坐标单位分别是“好男人”特质（细心、体贴、情感依托）和“坏男人”特质（冒险精神、对异性的吸引力），那么，和我交往了一年的男友，在前一条坐标轴上的位置会很高，而在后一条坐标轴上的位置会比较低。过去我觉得这种状况没什么不好，但现在我感觉到自己很难被他吸引，也搞不清楚自己是否想把这段关系继续下去。我的偏好曲线是否已朝着更钟情于“坏男人”特质的方向移动了呢？我知道过去的一年会成为沉没成本，但我不想那么轻易地放弃这样一个好男人。

比阿特丽斯(Beatrice)

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亲爱的比阿特丽斯，

收到一封把如此大量的消费者选择理论压缩到这么短篇幅的来信，真是让人高兴，不过我觉得你的问题中隐藏着一些混乱。你谈到了一条在好男人与坏男人特质之间做出取舍的偏好曲线。（顺便提一句，我建议用“无差异曲线”这一术语，因为从专业角度来讲，它更为准确，而且它会让你听上去既性感又可望而不可及。）然而，你并未说明自己的预算限制。照你的说法，你好像可以有一个体贴的男友，也可以有一个性感的男友，但不能两者兼得。我不知道你为什么会这么认为。或许你应该多和经济学家打打交道。

不过，让我们从表面来谈你的问题，并且假设，你的确无法找到一个十全十美的男人。如果是这样，你所描述的情况就再寻常不过了：它是个收益递减问题。只有小孩子才会希望餐餐都吃自己最喜爱的食物，或者把同样一个故事听上一遍又一遍。对于我们中的大多数人来说，多样性才是生活的调味剂。既然如此，就甩掉你的男友，另外找个花花公子交往一年看看。新恋情必然在泪水中收场，到时候你可以再给自己物色一个长相对不起观众、沉闷乏味但真正关心你的男人。这样的人并不少。
（译者/章晴）

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Solve my good boy, bad boy dilemma
By Tim Harford 2009-09-18

Dear Economist,

Suppose we plot my preference curve for a man as units of “good boy” traits (thoughtfulness, caring, emotional support) versus “bad boy” traits (adventurousness, sexual attractiveness). My boyfriend, whom I've been dating for a year, would come up very high on the former and low on the latter. This situation was fine for me before, but now I'm having a hard time being attracted to him and I wonder if I want to continue the relationship. Has my preference curve simply shifted more in favour of the “bad boy” traits? I know the one year is a sunk cost, but I'm reluctant to give up so easily on such a nice man.

Beatrice

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Dear Beatrice,

It is a pleasure to receive a letter that packs so much consumer choice theory into so little space – although I sense a creeping confusion in your question. You speak of a preference curve expressing a trade-off between good boy and bad boy traits. (By the way, I recommend the term “indifference curve”, both because it is technically more precise, and because it makes you sound sexy and unavailable.) Yet you do not specify your budget constraint. You act as if you can have a thoughtful boyfriend or a sexy boyfriend, but not both. I wonder why you think this is true. Perhaps you should hang around with economists more.

Let us take your problem at face value, though, and assume that you cannot simply find a man who has it all. If so, the problem you describe is familiar enough: that of diminishing returns. Only little children want to eat their favourite food for every meal, or listen to the same story again and again. For most of us, variety is the spice of life. So dump your boyfriend and find a rogue. Date him for a year. It is bound to end in tears, and then you can find yourself another ugly, tedious – yet thoughtful – man. They are not in short supply.