Day 098 — Reading: Theories on the Origins of Human Language

背景知識

Reading Day — 火曜

今日は Academic Reading — Evolutionary Biology & Linguistics（言語の起源） の練習です。テーマは 「人類の言語はどのように生まれたのか」 — 進化生物学・心理学・言語学が交差する、IELTS Academic で頻出のアカデミックトピックです。

設問形式	今日の出題数	攻略ポイント
Matching Features	4問（Q1〜4）	人物名をキーワードにスキャンし、主張内容と照合する
Multiple Choice	5問（Q5〜9）	「部分的に正しい」引っかけ選択肢を除外する
Sentence Completion	4問（Q10〜13）	NO MORE THAN TWO WORDS でパッセージから抜き出す

今日のテーマ: 言語の起源に関する4つの理論
protolanguage（原初言語）・sexual selection（性淘汰）・vocal grooming（音声グルーミング）・mirror neurons（ミラーニューロン） などの語彙が登場します。ダーウィン・イェスペルセン・ダンバー・コーバリスという実在の研究者の理論を扱います。

Matching Features 攻略法

形式	問われる内容	攻略法
Matching Information	その情報が「どの段落」にあるか	設問キーワードでパッセージ全体をスキャン
Matching Headings	その段落の「主題」は何か	各段落の最初・最後の文を中心に主旨をつかむ
Matching Features	「誰が/何が」その主張をしたか	選択肢の固有名詞（人物名）でスキャンし、主張を照合

最頻出ミス: Matching Headings との混同
Matching Features は段落全体の要旨ではなく、特定の人物が何を主張したかを問う。段落と人物の対応表を先に作ってから設問に取り組むと速い。
「NB You may use any letter more than once」の指示がある場合、同じ人物が複数の設問の答えになることもある。

パッセージ

⏰ 目安: パッセージ読解 8分 / 設問 12分

READING PASSAGE

THEORIES ON THE ORIGINS OF HUMAN LANGUAGE

A The origins of human language remain one of the most tantalising puzzles in the study of human evolution. Unlike bones or tools, speech leaves no trace in the fossil record, so scholars cannot examine direct physical evidence of the earliest utterances. Instead, researchers have pieced together competing hypotheses by comparing human language with the communication systems of other primates, examining the anatomy of ancient hominin skulls and vocal tracts, and drawing on principles from linguistics, psychology, anthropology and, more recently, neuroscience. So numerous and so difficult to test were the resulting proposals that, in 1866, the Linguistic Society of Paris formally banned papers on the topic from its proceedings, judging the debate to be founded on speculation rather than verifiable evidence. Only in recent decades, aided by advances in genetics, primatology and brain imaging, has the question re-emerged as a legitimate field of rigorous scientific inquiry.

B One of the earliest scientific theories was put forward by the naturalist Charles Darwin, who proposed in The Descent of Man (1871) that human language may have developed out of musical, song-like calls. Darwin drew a direct comparison with birdsong, suggesting that early hominins, like many bird species, first produced rhythmic vocalisations to attract mates, and that these courtship calls were only later adapted for other, more practical communicative purposes. This idea, sometimes labelled the ‘musical protolanguage’ hypothesis, situates the roots of language not in any pressing need to exchange practical information about food or danger, but in emotional expression and sexual selection — the same evolutionary pressure that produces the elaborate songs of many birds today.

C The Danish linguist Otto Jespersen extended this musical line of thinking in the early twentieth century with what has become known as the sing-song theory. Jespersen argued that the earliest human utterances more closely resembled singing than the clipped, efficient prose of modern speech: long, emotionally charged sequences of sound that were only later broken down into the smaller, discrete units that we now recognise as individual words. In his view, the analytical grammar of contemporary languages, with its neat separation of nouns, verbs and other parts of speech, represented a comparatively late development, layered on top of an original and altogether more musical mode of vocal expression.

D A markedly different explanation comes from the evolutionary psychologist Robin Dunbar, who has proposed what is often referred to as the social grooming, or ‘gossip’, hypothesis. Dunbar observed that non-human primates maintain social bonds largely through physical grooming, a slow and inherently one-to-one activity. As early human groups grew steadily larger, he argued, it became practically impossible for any individual to groom every other member of the group by hand, and so language evolved as a form of ‘vocal grooming’ — a means of maintaining social relationships with many people simultaneously, through conversation and gossip, rather than through touch alone.

E A third strand of research, associated most prominently with the psychologist Michael Corballis, locates the origins of language not in sound at all, but in gesture. Pointing to the sophisticated and remarkably flexible use of manual gestures among chimpanzees and other primates, and to the discovery of so-called ‘mirror neurons’ — brain cells that fire both when an animal performs a particular action and when it merely observes that same action performed by another — Corballis has argued that early hominins first developed a rich system of communicative hand movements. Only later, he suggests, as the vocal apparatus gradually evolved and the hands became occupied with tool use, was this gestural system progressively translated into speech.

F None of these theories can, at present, be conclusively proven or disproven, and each continues to attract both supporters and vocal critics. Sceptics of the musical theories point out that birdsong and human speech serve very different neurological functions; opponents of the gestural theory note that it struggles to explain why speech, rather than sign language, ultimately became dominant. What is increasingly clear, however, is that the question of how language began cannot be answered by linguistics alone: it now draws on primatology, neuroscience, genetics and archaeology in combination, and continues to generate lively debate more than a century and a half after the Linguistic Society of Paris first tried to silence it.

設問

Questions 1–4: Matching Features

Look at the following statements and the list of researchers below. Match each statement with the correct researcher, A–D.

NB You may use any letter more than once.

A. Charles Darwin
B. Otto Jespersen
C. Robin Dunbar
D. Michael Corballis

compared early communication to the courtship displays of another species

connected the origins of communication to a discovery about brain cells that respond to observed actions

suggested that grammar developed after an earlier, more musical form of expression

linked the origin of language to changes in the size of social groups

Questions 5–9: Multiple Choice

Choose the correct letter, A, B, C or D.

Why did the Linguistic Society of Paris ban papers on the origin of language in 1866?

A. They believed the field belonged to philosophy rather than science.

B. They judged the debate to rest on speculation that could not be tested.

C. They wanted researchers to focus on other pressing linguistic questions.

D. They had concluded that language originated from a single ancestral tongue.

According to the passage, what evidence supports Corballis's gestural theory?

A. Fossilised remains of the vocal tract in early hominins

B. The flexible use of gestures among primates and the discovery of mirror neurons

C. A comparison between human speech and birdsong

D. Observations of grooming behaviour among primate groups

What problem does Dunbar's hypothesis claim language evolved to solve?

A. The difficulty of coordinating group hunting activities

B. The limits of physical grooming as group size increased

C. The need to communicate about abstract concepts

D. The transition from gesture-based to vocal communication

What criticism of the gestural theory is mentioned in the passage?

A. It cannot account for why speech became more common than sign language.

B. It relies on evidence from extinct species that cannot be studied.

C. It contradicts findings about mirror neurons.

D. It assumes that all primates communicate in the same way.

What does the final paragraph suggest about current research into the origins of language?

A. One theory has now been widely accepted as correct.

B. The debate has been abandoned as unanswerable.

C. It increasingly depends on the combination of multiple academic disciplines.

D. New fossil evidence has resolved the main disagreements.

Questions 10–13: Sentence Completion

Complete the sentences below. Use NO MORE THAN TWO WORDS from the passage for each answer.

Darwin believed early hominins used rhythmic calls mainly to attract ______.

Jespersen thought that individual words only emerged once early song-like sounds were broken down into smaller ______.

Dunbar argued that as groups became too large, people could no longer ______ every member by hand.

Corballis suggested that gestures were gradually replaced by speech once the hands became occupied with ______.

有用な語彙・表現

語彙・表現	日本語訳	使用例
tantalising	じれったい・悩ましい	one of the most tantalising puzzles
protolanguage	原初言語	the ‘musical protolanguage’ hypothesis
courtship	求愛	these courtship calls were only later adapted
sexual selection	性淘汰	emotional expression and sexual selection
discrete (adj.)	個別の・離散的な	broken down into discrete units
vocal grooming	音声による毛づくろい	language evolved as a form of vocal grooming
mirror neurons	ミラーニューロン	the discovery of mirror neurons
vocal apparatus	発声器官	as the vocal apparatus gradually evolved
sceptic	懐疑論者	sceptics of the musical theories
dominant (adj.)	優勢な・支配的な	speech... ultimately became dominant

ヒント

各段落は基本的に1人の研究者に対応する（B=Darwin, C=Jespersen, D=Dunbar, E=Corballis）。まず段落と人物の対応表を作ってから、記述文の内容がどの段落の主張と一致するかを照合する。

Q1: "courtship displays of another species" → 段落Bの birdsong（鳥の求愛）との比較。
Q2: "brain cells that respond to observed actions" → 段落Eの mirror neurons の説明。
Q3: "grammar developed after... musical form" → 段落Cの sing-song theory。
Q4: "changes in the size of social groups" → 段落Dの集団規模の変化。

各選択肢を本文と1文ずつ照合し、「一部だけ一致する」引っかけを除外する。特にQ8は「ジェスチャー理論そのものへの批判」を探す設問であることに注意。

Q5: 段落Aの "speculation rather than verifiable evidence" に対応する選択肢を選ぶ。
Q8: 段落Fの "opponents of the gestural theory note that..." の直後を確認する。
Q9: 段落Fの最後の文全体（複数分野の統合）が根拠になる。

Sentence Completion のコツ: 空所の前後の語句をそのままパッセージ内で検索し、文法的に自然につながる語句を抜き出す。語数制限を必ず守る。

Q10: 段落Bの "attract ___" の直後の語をそのまま抜き出す。
Q11: 段落Cの "smaller, ___ units" の空所部分（形容詞+名詞で2語）。
Q12: 段落Dの "___ every other member of the group by hand" に当てはまる動詞1語。
Q13: 段落Eの "occupied with ___" の直後の名詞句をそのまま抜き出す（2語）。

解答・解説

問	解答	パッセージの根拠
1	A. Charles Darwin	Paragraph B: "Darwin drew a direct comparison with birdsong... first produced rhythmic vocalisations to attract mates" 鳥の求愛と早期の交信を比較している
2	D. Michael Corballis	Paragraph E: "the discovery of so-called 'mirror neurons' — brain cells that fire... when it merely observes that same action" 観察行動に反応する脳細胞の発見と紐づけている
3	B. Otto Jespersen	Paragraph C: "the analytical grammar of contemporary languages... represented a comparatively late development, layered on top of... a more musical mode" 文法は音楽的表現の後に発達したと主張
4	C. Robin Dunbar	Paragraph D: "As early human groups grew steadily larger... language evolved as a form of 'vocal grooming'" 集団規模の変化と言語の起源を結びつけている

問	解答	パッセージの根拠
5	B	Paragraph A: "judging the debate to be founded on speculation rather than verifiable evidence"
6	B	Paragraph E: "the sophisticated and remarkably flexible use of manual gestures among... primates, and to the discovery of... mirror neurons"
7	B	Paragraph D: "it became practically impossible for any individual to groom every other member of the group by hand"
8	A	Paragraph F: "opponents of the gestural theory note that it struggles to explain why speech, rather than sign language, ultimately became dominant"
9	C	Paragraph F: "the question... cannot be answered by linguistics alone: it now draws on primatology, neuroscience, genetics and archaeology in combination"

問	解答	根拠（パッセージ）
10	mates	Paragraph B: "first produced rhythmic vocalisations to attract mates"
11	discrete units	Paragraph C: "broken down into the smaller, discrete units that we now recognise as individual words"
12	groom	Paragraph D: "it became practically impossible for any individual to groom every other member of the group by hand"
13	tool use	Paragraph E: "the hands became occupied with tool use"

語数制限のポイント: Q11 は "units" だけでは不十分（"discrete" を含めて2語）。Q13 は "tool" だけでなく "tool use" まで含めるのが正確。

よくある日本人のミス

ミス	原因	正しいアプローチ
Matching Features を Matching Headings と混同する	段落全体の要旨で探してしまう	選択肢の固有名詞（人物名）をキーワードにスキャンし、主張内容と照合する
Sentence Completion で語数制限を超える	"NO MORE THAN TWO WORDS" を見落とす	制限語数を必ず確認し、余分な語や冠詞を含めない（Q11は2語ちょうど）
Multiple Choice で部分的に正しい選択肢を選ぶ	本文中の語句と一部一致しただけで飛びつく	選択肢全体の主張が本文と完全に一致するか確認する（Q8のひっかけに注意）
Q13で "tool" のみを解答する	語群の切れ目を誤認する	"occupied with tool use" という名詞句全体を抜き出す
全文を精読してから設問に取り組む	時間管理の意識が低い	設問キーワードを先読みしてからスキャン。20分で13問 ≈ 1.5分/問

次のステップ

発展: 段落Fの「ジェスチャー理論 vs 音声理論」の対立構造を使って、「Which theory do you find most convincing, and why?」というSpeaking Part 3形式の口頭練習をしてみる
次回予告（水曜）: Vocabulary & Grammar — Academic Word List（Science & Society）+ コロケーション

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