測測看你有多聰明？

Although a full IQ test takes an hour or more and costs hundreds of pounds, performance on this one simple test is highly predictive of your overall intelligence.

雖然一個完整的智商測試需要一個小時或者更長，並且花費上千元，但這個簡單的測試卻可以高度預言你的大概智商。

Look at the four cards above. We know for a fact that each card has a letter on one side and a number on the other. Truthful Terry says: ‘Every card that has a D on one side has a 3 on the other.’ What is the fewest number of cards you need to turn over to find out whether Truthful Terry is actually telling the truth? And which ones? The answer is shown at the bottom of the page.

請看上面的四張卡片。我們已知每張卡片都是一面有字母，另一面數字。Truthful Terry說：“每張一面含字母D的卡片，其另一面都是數字3。”你需要翻至少幾張牌來確定Truthful Terry究竟有沒有說實話？具體又要翻哪張牌呢？答案在文章結尾。

If you got it right, congratulations! Either you’ve seen this before or you’re a candidate for Mensa.

如果你回答正確，恭喜！或許你之前看過這個，或許你是世界頂級智商俱樂部門薩的成員。

Seriously, I’ve given this test to hundreds of people up and down the country, and very few get it right (the exception was an audience of Google software engineers, not a single one of whom messed up). The analytical and deductive skills you’ve shown are one of the most important components of intelligence.

事實上，我把這個測試給全國成百上千的人做了，幾乎沒有人能做對（谷歌的軟件工程師們一個也沒做對，只有一個他們的觀衆是個例外）。你所展示的分析和推斷能力是智商最重要的組成部分之一。

If you slipped up, don’t worry. The reason is a phenomenon known as confirmation bias. Most people, being charitable sorts, want to turn over the 3, find a D on the back and say: “Well done, Terry!” Actually it doesn’t matter whether the letter on the back of the 3 is D, Z or something else (look back to what he actually said).

如果你答錯了，不要擔心。這是源於一個名爲認知偏見的現象。大多數人作爲善良的羣體，希望翻開卡片3，發現背後的D，然後說：“做得好，Terry！”事實上，無論在卡片3的背後是字母D，Z或是其他，都無所謂。（回去看一下他究竟說了什麼）

Confirmation bias – the tendency to try to confirm pre-existing beliefs – is one reason many people believe complete nonsense (eg homeopathy).

認知偏見——趨向於證實預前存在的信念——是許多人相信完全胡說八道的事情的原因（比如順勢醫療法）。

Ironically the only way to check the truth of Terry’s statement is to try to disconfirm it – ie to try to find evidence that he is wrong (a D on the other side of the 7).

相反的是，唯一確認Terry的說法是正確的方法就是證明其不成立，也就是說找到他是錯的證據（在卡片7的背後發現字母D）。

Answer：Two cards, D and

答案：至少翻2張卡片，卡片D和卡片7