雅思阅读 102: When the Number Three Tastes Like Strawberries（数字三尝起来像草莓）

改编自 PMC / Frontiers in Human Neuroscience（2013–2024年）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：https://pmc.ncbi.nlm.nih.gov/articles/pmid/22131906/

Reading Passage

A. For most people, the senses stay in their lanes. A trumpet sound is heard and not seen; the letter "A" on a page is read in black and never tasted. For a small minority, the lanes dissolve. Number forms carry colour, musical notes evoke flavours, and the word "three" may, with unwavering regularity, taste of strawberries on the tongue. No one is pretending; the synesthete experiences these extra senses as plainly as the rest of us see the sky, and finds it difficult to believe that others do not. This blending of senses is called synesthesia, from the Greek for "feeling together". Its most common variety is grapheme-colour synesthesia, in which letters and numbers reliably carry a specific hue — one person's "A" is invariably red, another's always blue. Once dismissed as a fanciful metaphor or a child's game, The trait has become, over the last quarter-century, a serious object of neuroscience, because it offers a rare window onto a question that puzzles scientists: how does the brain bind separate sensations into a single, coherent world? Ordinary people take this binding for granted; the synesthete, by a happy accident, does not. Synesthetes, in a sense, experience a small, natural leak between the very modules the rest of us keep sealed.

B. The first challenge for researchers was simply to prove the experience was real rather than invented. Early sceptics suspected synesthetes were merely imagining associations or had memorised a private system. The decisive evidence came from consistency. When synesthetes are asked to match colours to letters, they choose the same shade year after year, far more reliably than non-synesthetes asked to guess — a stability that no act of memory could easily maintain across a decade. Their colours also behave perceptually: when a field of black "twos" is scattered among black "fives", grapheme-colour synesthetes spot the embedded shape faster, because their tinted twos pop out from the crowd of differently tinted fives. You cannot "remember" your way out of a perceptual pop-out; the effect betrays a genuine, automatic visual experience, felt rather than rehearsed. That automaticity is what distinguishes it from the vivid metaphor of a poet, who may say that a sound is "blue" knowing full well it is not. When a synesthete insists the letter is red, they are not being fanciful; for them, it genuinely is.

C. The leading explanation grew out of anatomy. In the visual brain, the region that recognises written letters and numbers — the visual word form area, tucked in the fusiform gyrus — sits remarkably close to the region that processes colour, known as area V4. The cross-activation theory, proposed by Ramachandran and Hubbard, argues that in synesthetes these neighbouring regions are slightly over-connected, so that recognising a letter automatically fires up the colour area next door, producing a percept of colour where no colour is on the page. It is, in essence, a short circuit between two otherwise separate maps of the outside world. Imaging bore out the first half of the claim: when synesthetes look at black letters, their V4 lights up, and it does so as early as a hundred and ten milliseconds after the stimulus — about as quickly as colour produced by the eye itself. Non-synesthetes show no such response, which is what makes the effect feel like evidence rather than imagination. The black ink on the page really does light up a colour centre in the mind's eye, and it does so within the blink of an eye, before the synesthete has time to decide what to see.

D. The neat story has, however, grown thornier as the scans have multiplied. Some teams did find extra connectivity in the white matter linking the two regions, but others, scanning larger groups, failed to confirm the predicted hyperconnectivity, reporting instead subtler differences in the shape of cortical tissue spread across several lobes. Meanwhile a separate line of work measured a chemical called BDNF, which supports the brain's ability to rewire itself, and found higher levels in synesthetes than in matched controls — hinting that the trait may reflect a general state of heightened neural plasticity rather than one faulty wire. The field has not settled on a single mechanism; it is equally clear that something in the brains of synesthetes genuinely differs, and that the simple "crossed wires" diagram will not carry all the weight. The wiring may be real, but it is one thread in a larger and still-unfinished picture, woven also by chemistry, development and perhaps by habit.

E. Nor is synesthesia a disorder to be cured. Those who have it often describe it as a quiet blessing — coloured letters lend themselves to vivid memory, and the extra layer of sensation is usually pleasant rather than confusing. Few would give it up, and most assume, wrongly at first, that everyone sees the world this way. Its scientific importance lies precisely in being a normal variation of the brain rather than a disease. By asking why some people's senses leak into one another, researchers are, in effect, studying the more ordinary question of why the rest of us keep them so rigidly apart. The neatly divided senses that most of us take for granted, in this light, look less like the default of nature than like a hard-won achievement of a brain that has learned not to confuse its channels. The person for whom three tastes like strawberries is not, after all, broken; they are an experiment evolution left running, revealing how arbitrary the neatly divided senses of the average mind really are. For the synesthete, the world is a slightly more cross-wired, and rather more colourful, place to live — and the rest of us, in studying them, learn a little more about how our own senses were ever kept apart.

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 genuine blending of the senses ii. Proving the experience is not just imagination iii. The near-neighbours in the visual cortex iv. Where the simple crossed-wires theory runs into trouble v. Why synesthesia is a gift, not a disease vi. The history of coloured painting vii. Why everyone should learn to taste numbers

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. What is the most common form of synesthesia? A. Sound evoking touch. B. Letters and numbers evoking colours. C. Smell evoking sound. D. Taste evoking pain.

6. Why is the "consistency" evidence important? A. It shows synesthetes choose the same colours to letters year after year. B. It proves synesthetes have worse memories. C. It shows the associations are made up. D. It demonstrates that everyone is a synesthete.

7. According to the cross-activation theory, why does a black letter evoke colour? A. The letter region is near the colour-processing region and over-fires it. B. The eyes are damaged and see false colours. C. The synesthete wears coloured glasses. D. The letter is physically printed in colour.

8. What complication did later, larger scans introduce? A. They proved synesthesia has no neural basis at all. B. They sometimes failed to confirm the predicted extra connections. C. They showed that V4 never activates. D. They found that synesthetes have smaller brains.

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. Grapheme-colour synesthetes can find an embedded shape faster when their letters carry colours.
10. Area V4 in synesthetes begins responding to black letters roughly as quickly as the visual cortex responds to real colour.
11. All imaging studies have fully confirmed the original cross-activation theory.
12. Synesthetes had higher measured levels of BDNF than matched controls.
13. Most synesthetes find their experience unpleasant and wish it would stop.

Questions 14-15

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

The region that recognises written letters lies close to the colour-processing area known as V4; synesthetes' brains may reflect a general state of heightened neural (14) __________ rather than a single faulty (15) __________.

答案与解析

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