EigoPro 準1級読解 — The Wisdom and Madness of Crowds

Ask a large crowd to guess the number of jellybeans in a jar, and a curious thing happens: the average of all the guesses is often nearer the truth than almost any single guess, including those of self-styled experts. This phenomenon, popularised as "the wisdom of crowds," rests on a simple statistical insight. Individual errors scatter in every direction, and when they are pooled, the overestimates and underestimates tend to cancel out, leaving a collective judgement of surprising accuracy. It is the logic that underpins prediction markets, search-engine rankings, and the everyday faith we place in aggregated reviews. Yet the same crowds that appear so shrewd can, under different conditions, behave with spectacular folly. The decisive variable is independence. A crowd is wise only when its members reach their conclusions separately; the moment they begin to watch and imitate one another, the statistical magic evaporates. In a celebrated experiment, participants asked to judge the length of a line gave plainly wrong answers simply because the people before them had done so. Here lies the paradox: the very sociability that makes us human also makes us prone to herding, to bubbles, and to panics in which each person is merely echoing the person beside them. This distinction matters far beyond the laboratory. Financial manias, viral misinformation, and the abrupt collapse of once-unshakeable regimes all share a common signature—a cascade in which individuals abandon their private judgement and defer to the apparent consensus. Designers of institutions, then, face a delicate task. They must harness the aggregating power of many minds while shielding those minds from the contagion of one another's opinions. The crowd is neither sage nor mob by nature; which face it shows depends entirely on whether its members are permitted, and encouraged, to think for themselves.

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この単元の問題を3問、解説つきで公開しています

準1級 · 読解 · 全5問

問 1

What is the main idea of the passage?

Crowds always produce more accurate judgements than individual experts do.
Whether a crowd judges wisely or foolishly depends on whether its members think independently of one another.
Human sociability is the single greatest asset in collective decision-making.
Statistical averaging is unreliable and should not be used to make decisions.

Phrase

The crowd is neither sage nor mob by nature; which face it shows depends entirely on whether its members are permitted ... to think for themselves.

準1級読解社会心理学主旨把握

⚡ひとことで

群衆が賢いか愚かかは、構成員が独立して考えるか否かで決まる、が論旨。

選択肢の解説Choice Analysis

「Whether a crowd judges wisely or foolishly depends on whether its members think independently of one another.」

正解

本文は (1) 平均化による『群衆の知恵』→ (2) 模倣が始まると魔法が消える『群衆の狂気』→ (3) 鍵は independence、という構成で進む。最終文 The crowd is neither sage nor mob by nature ... depends entirely on whether its members are permitted ... to think for themselves が結論。したがって『群衆が賢く判断するか愚かに判断するかは、構成員が互いに独立して考えるか否かで決まる』が主旨。

「Crowds always produce a great deal more accurate judgements than any of the individual experts do.」
= 群衆は常に専門家より正確 ━ 本文は『独立しているときだけ』賢いと条件を付けており always ではない。模倣下では spectacular folly に陥る。
「Statistical averaging is quite unreliable and ought never to be used in making any decisions.」
= 統計的平均化は当てにならない ━ 本文は平均化を surprising accuracy の源として肯定的に紹介しており逆。
「Human sociability is by far and away the single greatest asset in collective decision-making.」
= 人間の社交性こそ最大の資産 ━ 本文は社交性が herding や panics の原因にもなると述べており、単純な資産扱いはしていない。

▦Collocation

パターン	意味	例
the wisdom of crowds	群衆の知恵	popularised as the wisdom of crowds
cancel out	相殺される	errors cancel out
rest on ~	~に基づく	It rests on a statistical insight.
think for oneself	自分の頭で考える	encouraged to think for themselves
by nature	本来	neither sage nor mob by nature

❝例文

The pooled estimate rests on a simple statistical insight.
集計推定値は単純な統計的洞察に基づく。
Errors in every direction tend to cancel out.
あらゆる方向の誤差は相殺される傾向がある。
Each member was encouraged to think for himself.
各人が自分の頭で考えるよう促された。

💡Tip · 覚えるコツ

主旨設問は最終段の結論文を探すと速い。本文は『neither A nor B ... depends entirely on ~』という条件提示型の結論で、二面性を統合する答えが正解。

問 2

According to the passage, why does pooling many guesses often yield an accurate estimate?

Each member secretly copies the most knowledgeable person present.
Most people in a crowd happen to be experts on the question asked.
Large groups eliminate the need for any statistical calculation.
Individual overestimates and underestimates tend to cancel one another out when combined.

Phrase

the overestimates and underestimates tend to cancel out, leaving a collective judgement of surprising accuracy

準1級読解社会心理学詳細把握

⚡ひとことで

多数の推測を集めると過大評価と過小評価が相殺され、平均が正確になる。

選択肢の解説Choice Analysis

「Individual overestimates and underestimates tend to cancel one another out when combined.」

正解

第1段で Individual errors scatter in every direction, and when they are pooled, the overestimates and underestimates tend to cancel out と説明する。これを言い換えた『個々の過大評価と過小評価は、合算されると互いに相殺される傾向がある』が正解。専門知識ではなく誤差の打ち消し合いが鍵である点が要旨。

「Most of the people in any crowd happen to be experts on the question being asked.」
= 大半が専門家だから ━ 本文はむしろ self-styled experts ですら平均に劣ると述べており、専門知識が理由ではない。
「secretly copies the most knowledgeable person」
= 最も詳しい人を密かに真似る ━ 模倣は精度を破壊する要因として後段で否定されている。正反対。
「Large groups eliminate the need for any kind of statistical calculation at all.」
= 統計計算が不要になる ━ 現象自体が statistical insight に基づくので逆。

▦Collocation

パターン	意味	例
cancel out	相殺し合う	The errors cancel out.
scatter in every direction	あらゆる方向に散らばる	Errors scatter in every direction.
pool ~	~を集約する	when the guesses are pooled
collective judgement	集合的判断	a collective judgement of accuracy
of surprising accuracy	驚くほど正確な	a judgement of surprising accuracy

❝例文

When the guesses are pooled, the errors cancel out.
推測を集約すると誤差は相殺される。
Individual errors scatter in every direction.
個々の誤差はあらゆる方向に散らばる。
The collective judgement was of surprising accuracy.
集合的判断は驚くほど正確だった。

💡Tip · 覚えるコツ

detail 設問は本文の語を別語に置換した選択肢が正解になりやすい (cancel out→cancel one another out, pooled→combined)。理由を問われたら because 相当の機構を述べた行を探す。

問 3

What does the passage identify as the common feature of financial manias and viral misinformation?

A cascade in which people set aside their own judgement to follow the apparent consensus.
An absence of any communication among the people involved.
A sudden improvement in the accuracy of collective judgement.
A deliberate conspiracy organised by a small group of insiders.

Phrase

all share a common signature—a cascade in which individuals abandon their private judgement and defer to the apparent consensus

準1級読解社会心理学詳細把握

⚡ひとことで

金融狂乱・偽情報拡散の共通点は、私的判断を捨てて見かけの合意に従う連鎖。

選択肢の解説Choice Analysis

「A cascade in which people set aside their own judgement to follow the apparent consensus.」

正解

第3段で Financial manias, viral misinformation ... all share a common signature—a cascade in which individuals abandon their private judgement and defer to the apparent consensus と明言する。これを言い換えた『私的判断を脇に置き、見かけの合意に従う連鎖』が正解。

「A deliberate conspiracy that has been organised by a small group of insiders.」
= 少人数による意図的な陰謀 ━ 本文は陰謀ではなく自発的な追従の cascade として描いており、組織された陰謀ではない。
「absence of any communication」
= 意思疎通の欠如 ━ むしろ互いを見て真似る (watch and imitate) ことが原因なので逆。
「A sudden improvement in the overall accuracy of the collective judgement made.」
= 精度の急向上 ━ manias や misinformation は誤りの拡大であり、精度向上ではない。

▦Collocation

パターン	意味	例
share a common signature	共通の特徴を持つ	They share a common signature.
abandon one's judgement	判断を放棄する	individuals abandon their private judgement
defer to ~	~に従う	defer to the apparent consensus
a cascade in which ~	~という連鎖	a cascade in which people imitate
apparent consensus	見かけ上の合意	follow the apparent consensus

❝例文

The panic shared a common signature with earlier bubbles.
そのパニックは過去のバブルと共通の特徴を持っていた。
Investors abandoned their private judgement.
投資家たちは自らの私的判断を放棄した。
Each person deferred to the apparent consensus.
各人が見かけ上の合意に従った。

💡Tip · 覚えるコツ

『共通点』を問う設問は all share / a common ~ の直後 (ここでは dash 後の言い換え) に答えがある。dash (—) は定義・換言の合図。

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EigoPro 準1級 読解 — The Wisdom and Madness of Crowds

この単元の問題を3問、解説つきで公開しています

The crowd is neither sage nor mob by nature; which face it shows depends entirely on whether its members are permitted ... to think for themselves.

the overestimates and underestimates tend to cancel out, leaving a collective judgement of surprising accuracy

all share a common signature—a cascade in which individuals abandon their private judgement and defer to the apparent consensus

EigoPro 準1級読解 — The Wisdom and Madness of Crowds