## 字幕列表 影片播放

• Meet Lucy.

譯者: Lilian Chiu 審譯者: Helen Chang

• She was a math major in college,

見見露西。

• and aced all her courses in probability and statistics.

她在大學時主修數學，

• Which do you think is more likely: that Lucy is a portrait artist,

且在她所有的機率 及統計課中都出類拔萃。

• or that Lucy is a portrait artist who also plays poker?

你認為下列何者比較有可能： 露西是肖像畫家，

• In studies of similar questions, up to 80 percent of participants

或者露西是肖像畫家， 同時也會玩撲克牌？

• chose the equivalent of the second statement:

在類似問題的研究中， 高達八成的受試者

• that Lucy is a portrait artist who also plays poker.

會選擇相對於 第二個陳述句的答案：

• After all, nothing we know about Lucy suggests an affinity for art,

露西是肖像畫家， 同時也會玩撲克牌。

• but statistics and probability are useful in poker.

畢竟，從我們對露西的所知， 看不出她喜愛藝術，

• And yet, this is the wrong answer.

但統計和機率在撲克牌中很有用。

• Look at the options again.

但，這個答案是錯的。

• How do we know the first statement is more likely to be true?

再看一次那些選項。

• Because it's a less specific version of the second statement.

我們怎麼知道第一個陳述句 比較有可能是真的？

• Saying that Lucy is a portrait artist doesn't make any claims

因為它是第二個陳述句的 「較不明確版」。

• about what else she might or might not do.

說露西是肖像畫藝術家並沒有提到

• But even though it's far easier to imagine her playing poker than making art

她可以會做／不會做 哪些其他的事。

• based on the background information,

雖然，根據背景資訊，

• the second statement is only true if she does both of these things.

想像她玩撲克牌比想像 她做藝術更容易許多，

• However counterintuitive it seems to imagine Lucy as an artist,

但只有在她兩件事都會做時， 第二個陳述句才會成立。

• the second scenario adds another condition on top of that, making it less likely.

不論想像露西身為藝術家 是個多麼反直覺的想像，

• For any possible set of events, the likelihood of A occurring

第二個情況比第一個情況 又多加了一個條件，

• will always be greater than the likelihood of A and B both occurring.

讓可能性更低。

• If we took a random sample of a million people who majored in math,

對任何可能的事件組合， A 事件發生的機率

• the subset who are portrait artists might be relatively small.

一定會比 A 和 B 事件 同時發生的機率高。

• But it will necessarily be bigger

如果我們隨機抽出 一百萬名主修數學的人，

• than the subset who are portrait artists and play poker.

當中的肖條畫藝術家子集合 可能相對會很小。

• Anyone who belongs to the second group will also belong to the first

但它一定會大於

• but not vice versa.

會玩撲克牌的肖像畫 藝術家的子集合。

• The more conditions there are, the less likely an event becomes.

屬於第二群的人， 一定也會屬於第一群——

• So why do statements with more conditions sometimes seem more believable?

但反過來就不一定了。

• This is a phenomenon known as the conjunction fallacy.

條件越多，事件發生的機率就越低。

• When we're asked to make quick decisions, we tend to look for shortcuts.

所以，為什麼比較多條件的陳述句 有時看起來卻比較可信？

• In this case, we look for what seems plausible

這個現象就是所謂的 合取謬誤（交集偏誤）。

• rather than what is statistically most probable.

當我們被要求快速做決定時， 我們會傾向找截徑。

• On its own, Lucy being an artist doesn't match the expectations

在這個例子中，我們會去找 貌似可信的陳述句，

• formed by the preceding information.

而不是去找統計機率 最高的陳述句。

露西身為藝術家這件事情本身，

• gives us a narrative that resonates with our intuitions

並不符合前述資訊所形成的預期。

• it makes it seem more plausible.

關於她會玩撲克牌的額外細節資訊

• And we choose the option that seems more representative of the overall picture,

反而提供了和我們的 直覺呼應的描述——

• regardless of its actual probability.

讓它變得似乎更可信。

• This effect has been observed across multiple studies,

我們會去選擇看似比較能 代表整體狀況的選項，

• including ones with participants who understood statistics well

不論它實際的機率多高。

• from students betting on sequences of dice rolls,

在許多研究中都有 觀察到這種效應，

• to foreign policy experts predicting the likelihood of a diplomatic crisis.

包括找非常懂統計的人 來當受試者的研究在內——

• The conjunction fallacy isn't just a problem in hypothetical situations.

從讓學生針對一連串 擲骰子結果下注的研究，

• Conspiracy theories and false news stories

到外國政策專家預測外交危機 發生可能性的研究都有。

• often rely on a version of the conjunction fallacy to seem credible

合取謬誤並不只是在 假設情境中才會發生的問題。

• the more resonant details are added to an outlandish story,

陰謀理論和假新聞報導

• the more plausible it begins to seem.

通常都是看似可信的 合取謬誤版本——

• But ultimately, the likelihood a story is true

幫一個古怪的故事 加上更多能呼應的細節，

• can never be greater than the probability that its least likely component is true.

它就會顯得更像真的。

Meet Lucy.

B1 中級 中文 TED-Ed 露西 機率 撲克牌 可信 謬誤

# 你能智取這種邏輯謬誤嗎？- Alex Gendler (Can you outsmart this logical fallacy? - Alex Gendler)

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林宜悉 發佈於 2021 年 01 月 14 日