This is for investment professionals only and should not be relied upon by private investors
July 2014
Cognitive errors in investing
在投資認知誤區
ARE YOU AWARE OF “SUNK COST SYNDROME”?
你知不知道“沉沒成本綜合症”？
Have you ever gone to a show at the theatre that you didn’t like, and yet sat through it
to the end because you had paid good money to be there? Or forced yourself to finish
a book that you had struggled halfway through, because otherwise the effort you had
expended so far would be wasted? Or hung on to an underperforming employee
longer than perhaps you should have because you had put so much time and effort
into trying to turn that employee’s performance around, and didn’t want to give up
now? We have all done these things, or similar, because we are human, and human
brains are wired to do things in certain, sometimes illogical ways.
你有沒有去看過一場表演，你不喜歡戲劇，並通過它尚未坐到底，因為
你已經付好錢在那裡？或強迫自己去完成一本書，你一直在努力進行到
一半，因為如果你已經付出的努力迄今都浪費了？或掛在一個表現不佳
的員工長於也許你應該有，因為你已經把這麼多的時間和精力，試圖扭
轉該員工的表現，並沒有想放棄嗎？我們都做了這些事情，或者類似
的，因為我們是人，而人的大腦連接到做事一定，有時不合邏輯的方
式。
Clearly, all the above actions are illogical. If you have spent $100 dollars to go to the
theatre, then the $100 is gone. It is what’s known as a sunk cost. Nothing can bring it
back. So if you are not enjoying the show, you may as well leave and do something
you would enjoy more, such as get some dinner. Think about it. You can end the night
having spent $100 and had a good time, or end the night having spent $100 and
having tortured yourself by sitting through a boring show in an uncomfortable chair.
Which is better?
顯然，上述所有的動作都是不合邏輯的。如果你已經花了 100塊錢去影
院，那麼 100 美元的走了。這是什麼所謂的沉沒成本。沒有任何東西可
以把它帶回來。所以，如果你不喜歡的節目，你不妨離開，做一些事
情，你會享受到更多，比如獲得一些晚餐。想想吧。您可以結束當晚花
了 100 元，有一個很好的時間，或結束晚上花了 100 元，已經坐在過一
個無聊的節目在一個不舒服的椅子上折磨自己。哪一個更好？
Sunk cost syndrome is just one example of what are known as “cognitive errors”,
where emotion supercedes logic. Because we are human, it happens all the time, and
because investors, both professional and amateur, are human, it happens to them too.
In the world of finance and investing, the study of cognitive errors is known as
“behavioural finance”. Learning to recognize these behaviours, and then find ways to
try to counter them, is what separates the world’s most successful investors from the
rest of us. In the space I have here I cannot begin to cover them all, but we can look at
a couple more common ones to get the general idea.
沉沒成本綜合徵是所謂的“認知誤區”，其中的情感將取代邏輯只是一
個例子。因為我們是人，它發生的時間，因為投資者，專業和業餘的，
是人，它發生在他們身上了。在金融和投資的世界裡，認知錯誤的研究
被稱為“行為金融學”。學習認識這些行為，然後想方設法試圖對抗它
們，就是從我們其他人分開是世界上最成功的投資者。在空間我這裡，
我不能開始涵蓋所有，但我們可以看看幾個比較常見的得到的總體思
MATTHEW SUTHERLAND is Senior
Investment Director for Equities at
Fidelity Worldwide Investment, leading
the Asia-based equity product
specialists and investment directors.
Before taking up this role in late 2012,
he was Head of Research for Asia
Pacific, based in Japan.
路。
HOW TO STAY AWAY FROM THE “HERD”?
Perhaps the commonest of all, and one of the most important, is herd instinct. Herd
instinct is what makes people follow the crowd, and it works as strongly in investment
as it does in, say, fashion, or language. It is the main driving force behind the formation
of bubbles, and the crashes that inevitably follow them. Understanding herd instinct,
and avoiding it, is one of the best investment strategies there is. The dotcom bubble of
the late 1990s is a good example. Many investors would not have understood why
those internet stocks were being given such unbelievable valuations. But as the years
progressed, and the valuations went up and up, more and more people were sucked in
on the basis that all those other smart people out there must be right. But in the end
they were not right, as we know with the benefit of hindsight.
也許，最常見的是，也是最重要的一條，就是一哄而起。從眾心理是什
麼使人們隨波逐流，和它的作品一樣強烈的投資，因為它在，比如說，
時尚，或語言。它的背後是形成氣泡，這不可避免地跟隨他們的崩潰的
主要驅動力。了解一哄而起，避免它，是最好的投資策略有一個。上世
紀 90 年代末的互聯網泡沫就是一個很好的例子。許多投資者也不會明
白為什麼那些互聯網概念股被賦予這樣的令人難以置信的估值。但是，
隨著時間的進展，以及估值上升和上升，越來越多的人吸入的基礎，所
有其他的聰明人在那裡一定是對的。但最終他們沒有正確的，因為我們
知道事後的利益。
Warren Buffet, on the other hand, 4th richest man in the world in this year’s Forbes
magazine list, the so-called Sage of Omaha, and chairman of Berkshire Hathaway,
understands this herd phenomenon better than anyone. He was never sucked in to the
millennium dotcom bubble. He simply said he did not understand the business models
of these companies or how to value them, and so he stayed away. He was vilified for 2
years, by the press and by shareholders alike, for failing to participate, but in the long
run he was proven totally right.
沃倫·巴菲特，在另一方面，第四富有的人在世界上在今年的福布斯名
單，奧馬哈的所謂聖人，而伯克希爾·哈撒韋公司董事長，明白這一點一
哄而上比任何人都好。他從來沒有吸入千年網絡泡沫。他只是說，他不
明白這些公司或如何重視他們的商業模式，並讓他住了。他被誣衊為 2
年，由媒體和股東的一致好評，未能參加，但長期來看，他被證明完全
正確。
This ability to sell when others are buying and buy when others are selling is the best
long term investment strategy I know. Aside from Warren Buffet, other highly
successful investors have also been able to do this. Sir John Templeton coined the
phrase “the four most dangerous words in investing are ‘this time it’s different’” – a
phrase used to justify many bubbles through history, and a signal to sell in his eyes.
And John D. Rockefeller, one of the richest Americans a hundred years ago, coined
the equally memorable phrase “buy when there’s blood on the streets”. He meant that
when things look bad, very bad, and most other investors will be selling, you should be
buying. To do this you need two things. First, you need the ability to take a long term
view, because you may be wrong for a year or two before you are right; and secondly,
you need enormous discipline and strength of will.
這種能力，當別人都買賣，當別人都賣出買的是最好的長期投資策略，
我知道了。除了巴菲特，其他非常成功的投資者也能做到這一點。約翰·
鄧普頓爵士創造的短語“四大最危險的詞投資是”這一次是不同的“”
- 通過使用歷史證明許多氣泡的短語和信號在他眼裡出售。和約翰·D·洛
克菲勒，一百年前的一個最富有的美國人，創造了同樣令人難忘的那句
“買的時候有血街頭”。他的意思是，當事情看起來很糟糕，很糟糕，
和其他大多數投資者會賣出，你應該買。要做到這一點，你需要兩樣東
西。首先，你需要採取長遠的觀點的能力，因為你可能是錯的一兩年你
是對之前;其次，你需要巨大的紀律和意志的力量。
WHAT CAN YOU DO TO COMBAT CONFIRMATION BIAS?
A third very important cognitive error is called “confirmation bias”. This refers to the
human tendency to seek evidence to support a belief or theory already held. Let’s say
you believe the gold price is going to rise. Confirmation bias suggests that you will
seek evidence to support that view. You will listen to friends and colleagues who share
the view point, and ignore the comments of friends and colleagues who disagree,
thinking them ill-informed, or perhaps even stupid. You carefully read newspaper
articles that talk positively about gold, whilst skimming over those that disagree. And
you interpret ambiguous evidence or balanced articles as supportive of your position.
第三個非常重要的認知錯誤被稱為“確認偏誤”。這是指人類傾向於尋
求證據來支持一個信念或理論已經舉行。比方說，你認為金價會上漲。
確認偏誤認為，你會尋求證據來支持這一觀點。你會聽朋友和同事誰分
享觀點，而忽略了朋友，誰不同意同事的意見，認為他們不了解情況，
甚至可能是愚蠢的。您仔細閱讀談正對黃金，而一掠而過那些不同意報
紙上的文章。和您解釋模棱兩可的證據或平衡的文章作為支持你的立
場。
This phenomenon is so entrenched in human psychology that it can lead to huge
problems. The more emotive and less fact-based the view held, the more people tend
to suffer from confirmation bias, for example in religion. Confirmation bias ultimately
leads to attitude polarization, where holders of a given view become more and more
entrenched in their opinion, and angrier and angrier with those that hold the opposing
position. This can lead to political paralysis (as in the US budget process), or in
extreme, to religious wars.
這種現象使盤踞在人的心理，這可能會導致巨大的問題。更感性，少以
事實為依據的看法，更多的人傾向於從確認偏見之苦，例如宗教。確認
偏誤，最終導致兩極分化的態度，在一個給定觀點的持有者越來越盤踞
在他們看來，和越來越憤怒與那些持反對立場。這可能會導致政治癱瘓
（如美國預算過程），或在極端情況下，宗教戰爭。
What can you do to combat confirmation bias? Investors need to take active steps to
avoid falling in to this trap. Charles Darwin, the famous English naturalist who
expounded his theory of evolution through natural selection in his book “On the Origin
of Species” in 1859, made an active practice of recording evidence that went against
his theory in a special notebook. This is a sensible step. Another sensible step is
deliberately to seek out people who don’t share your view, and instead of trying to
convince them of your view, just listen carefully to theirs. If you can list down the
counter arguments, and as rationally as possible decide if they are valid or not, you will
have gone a substantial way towards avoiding falling into the confirmation bias trap.
你能做些什麼，以打擊證實偏見？投資者需要採取積極措施，以避免這
種陷阱下降。查爾斯·達爾文，著名的英國博物誰在 1859 年闡述了他的
進化論自然選擇在他的著作“物種的起源”，做記錄的證據表明，去反
對他的理論在一個特殊的筆記本電腦的積極實踐。這是一個明智的一
步。另一種明智的步驟是刻意去尋找的人誰不同意，而不是試圖說服你
的觀點他們你的觀點，而且，只是認真聽取他們的。如果你可以列出向
下計數器參數，或合理地確定它們是否有效沒有，你就已經大幅度地朝
避免陷入確認偏誤陷阱。
I have only had space here to discuss three of the most common forms of cognitive
error – sunk cost; herd instinct; and confirmation bias. There are many, many more. If
you are interested in minimising the investment risks your human brain creates for you,
I suggest you explore some of the literature on the topic, such as “Thinking, Fast and
Slow” by Daniel Kahneman, “Your Money and Your Brain” by Jason Zweig, or “The Art
of Thinking Clearly” by Rolf Dobelli.
我只有空間在這裡討論三個認知錯誤的最常見的形式 - 沉沒成本;一哄而
起;與確認偏誤。還有很多很多。如果你有興趣在降低投資風險的人腦創
造了你，我建議你探討一些文學上的話題，如“思考，快與慢”丹尼爾·
卡尼曼，“你的錢，你的大腦”由Jason茨威格，還是“思維清晰的藝
術”由羅爾夫Dobelli。
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