雅思阅读 57: The Mind in the Arms（分布在八条腕足里的心灵）

改编自 Science / University of Chicago / Coral CoE（2025）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：https://www.science.org/content/article/octopuses-fall-rubber-arm-illusion-just-us

Reading Passage

A. Among all the animals without backbones, none has perplexed biologists quite like the octopus. It solves puzzles, remembers where it was rewarded, escapes from sealed jars, and changes its appearance in a fraction of a second to match a reef, a rock or a patch of sand. Yet it is a mollusc — more closely related, on the family tree, to a snail than to any monkey or raven. Its large brain and flexible behaviour evolved entirely independently of the vertebrate line, making the octopus the strongest example on Earth of what researchers call convergent intelligence: a complicated mind built from an architectural plan radically different from our own. Studying it therefore asks a deeper question than "how smart is an octopus?" It asks whether intelligence, given a different starting body and a different evolutionary history, inevitably converges on the same tricks — play, curiosity, deception, a sense of one's own body. In 2025, several experiments pushed that question in surprising new directions.

B. The first surprise is where the brain actually is. A typical octopus has around 500 million neurons in total, but only about a third of them sit in the central brain inside its head. The remaining two-thirds are distributed along its eight arms, each arm carrying roughly 40 million of them. In practice this means that an arm can probe a crevice, identify a crab, coil around it and haul it back, all without waiting for the central brain to approve each movement. Severed arms have been documented to continue reacting to touch for some time, which is less gruesome than it sounds because the arm is, in a real sense, a semi-autonomous exploratory agent. Research from the University of Chicago in 2025 showed that the neural circuitry controlling arm movement is segmented, allowing the animal to coordinate eight boneless limbs, each with hundreds of suckers, in ways that no robot yet matches. The octopus, in other words, thinks with its whole body, not with a single control centre.

C. The second surprise is the skin. An octopus can shift from mottled brown to coral pink, match the dappled light of a rock pool, and even alter the texture of its skin, all in less than a second. The puzzle is that octopuses are effectively colourblind. Their eyes, unlike ours, cannot discriminate the wavelengths that make up colour, so how do they choose the right pattern to match a multicoloured reef? The answer, emerging from recent work, is that the skin itself "sees." It contains light-sensing proteins and millions of individually controlled colour cells called chromatophores, along with reflective iridophores and white leucophores, forming a distributed control system that can adjust camouflage without waiting for instructions from the brain. The result is an animal that can disappear into its surroundings while, in the conventional sense, having no idea what colour it is. Camouflage becomes not a visual calculation but a reflexive, skin-level response, mediated by circuitry that bypasses the central brain altogether.

D. Yet the octopus is not merely a reflex machine. In July 2025, researchers reported that octopuses fell for the "rubber arm" illusion — the classic experiment in which a person watches a fake rubber hand being stroked in time with their own hidden hand and, after a while, begins to feel that the rubber hand is part of their body. That sense of bodily ownership was previously thought to be largely a feature of mammals. Octopuses, it turns out, experience something comparable: they reacted as though a fake arm being touched in synchrony with a real one belonged to them. This matters because it suggests that the octopus maintains an integrated, multisensory model of its own soft, boneless body — the kind of representation a brain needs to control eight limbs independently without losing track of where they all are. MRI work has also shown that different octopus brain regions light up for different cognitive tasks, hinting at specialised circuits that parallel, rather than copy, our own.

E. The last surprise is the cruelest. Most octopuses live only one to two years, and they die shortly after reproducing: the female wastes away guarding her eggs, and the male does not long outlast mating. It is a puzzle worth sitting with. Why evolve a brain capable of solving mazes, watching a rubber arm and vanishing into a reef, if the animal will not live long enough to accumulate much of what it learns? One line of argument is that octopus intelligence is less about long-term wisdom than about fast, flexible problem-solving in a short, dangerous life — every new situation must be met on the spot, because there is no parent to teach it and no next year in which to be cautious. Others note that the same distributed nervous system that makes the arms so clever also makes the animal sensitive to suffering, which is why welfare rules for octopus research have been tightened in several countries. An animal that is smart, short-lived and intensely reactive turns out to be the mirror in which we have finally had to ask what a mind, built along completely different lines, might be experiencing all along. Those questions are no longer purely philosophical. Because octopuses feel pain and solve problems, an increasing number of research oversight bodies now class them as sentient animals, requiring anaesthesia and housing standards that were once reserved for vertebrates. Fishery and aquaculture operations, too, are being asked to reckon with the fact that the animals they harvest are not reflexive molluscs but curious individuals whose escape attempts, play and boredom have been documented in tanks and in the wild. The octopus, in other words, has stopped being a curiosity and become a problem — for ethics, for philosophy, and for any simple theory of what a brain is for.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. A "brain" distributed across the eight arms ii. The camouflage paradox: colourblind yet perfect iii. Evidence for an integrated sense of body iv. The puzzle of a short, intensely smart life v. A history of commercial octopus fishing vi. How aquarium filters are designed vii. The classification of shellfish

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

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

5. Where are most of an octopus's neurons located? A. Entirely within the central brain. B. Roughly two-thirds are distributed in the arms. C. Only in the eyes. D. Only in the skin.

6. What did the 2025 "rubber arm" experiment suggest? A. Octopuses possess a sense of body ownership previously associated mainly with mammals. B. Octopuses cannot see any object at all. C. Octopuses refuse to touch anything unfamiliar. D. Octopuses prefer plastic toys to food.

7. How can octopuses match colours if they are effectively colourblind? A. Light-sensing cells in the skin help control colour cells. B. They guess and almost always get it wrong. C. They follow signals from other octopuses. D. They see ultraviolet light with their eyes.

8. What is unusual about the octopus's life history? A. It lives for several centuries. B. It has a short life and usually dies after reproducing. C. It never reproduces. D. It spends most of its life on land.

Questions 9-13

Do the following statements agree with the claims of the writer?

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

9. An octopus arm can continue to react to touch even when separated from the body.
10. Octopuses discriminate colours as well as humans do.
11. The neural control of octopus arms is fully centralised in the head.
12. The mimic octopus is reported to imitate more than a dozen other marine species.
13. Octopuses are now the preferred model organism for cancer research.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

Each octopus arm carries millions of neurons and can solve tactile problems semi-(14) __________, while the millions of colour-changing cells in the skin are known as (15) __________.

答案与解析

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