When the Mind’s Eye is Blind, It’s Hard to Picture an Image
心智眼失靈腦海無影像
By Carl Zimmer

In 2005, a 65-year-old retired building inspector paid a visit to the neurologist Adam Zeman at the University of Exeter Medical School in England. After a minor surgical procedure, the man – whom Dr. Zeman and his colleagues refer to as MX – had suddenly realized he could not conjure images in his mind.
2005年時，65歲的退休建築工頭造訪英格蘭艾克斯特大學醫學院的神經學家亞當．柴曼。動過小手術後，柴曼與同事稱做MX的這位男士猛然發現，腦海已不會浮現圖像。

Dr. Zeman couldn’t find the condition in medical literature. He was intriguing. For decades, scientists had debated how the mind’s eye works, and how much we rely on it to store memories and to make plans for the future.
柴曼在醫學文獻找不到此一狀況，感到好奇。幾十年來，科學家爭辯心智之眼如何運作，以及我們有多麼仰賴心智之眼儲存記憶、擘劃未來。

MX agreed to a series of examinations. He proved to have a good memory for a man of his age, and he performed well on problem-solving tests. His only unusual mental feature was an inability to form mental images.
MX同意接受一系列檢查，結果證實他的記憶力在同年齡者中不錯，問題解決測驗也表現優異，唯一不尋常的心智特徵是無法組成心像。

Dr. Zeman then scanned MX’s brain as he performed certain tasks. First, MX looked at faces of famous people and named them. The scientists found that certain regions of his brain became active, the same ones that become active in other people who look at faces.
後來柴曼在MX做某些動作時掃描他的腦部。首先，MX注視名人的臉並指認。科學家發現他大腦某些部位開始活躍，與其他人認臉時活躍的部位相同。

Then the scientists showed names to MX and asked him to picture their faces. In normal brains, some of those face-recognition regions again become active. In MX’s brain, none did.
接著科學家拿名字給MX看，要他想像名人的長相。在正常的大腦，某些認臉的部位會再度活躍。MX的大腦則沒反應。

Yet MX could answer questions that would seem to require a working mind’s eye. He could tell the scientists the color of Tony Blair’s eyes, for example, and name the letters of the alphabet that have low-hanging tails, like g and j. These tests suggested his brain used some alternate strategy to solve visual problems.
但MX能回答似乎需要心智之眼管用才能解決的問題。例如，他可以告訴科學家東尼．布萊爾（英國前首相）眼睛的顏色，認出收筆時下垂的字母，像是g和j。測驗顯示他腦部使用某些替代策略來解決視覺問題。

Since then, scientists have surveyed other people who say they cannot summon mental images – as if their mind’s eye were blind. Many of the survey respondents differed from MX in an important way. While he originally had a mind’s eye, they never did.
後來科學家又測驗過一些自稱無法喚起心像，彷彿心智之眼瞎了的人。多數受試者跟MX有一重大不同。MX原本有心智之眼，這些人從未有過。

Reported in the journal Cortex,the condition received a name: aphantasia, based on the Greek word phantasia, which Aristotle used to describe the power that presents imagery to our minds.
研究報告登在Cortex期刊，這狀況有了個名字aphantasia：源於亞里斯多德描述腦海浮現影像能力的希臘字phantasia。

If aphantasia is real, it is possible that injury causes some cases while others begin at birth.
如果aphantasia真的存在，有些可能是受傷所致，有些則是天生的。

Thomas Ebeyer, a 25-year-old Canadian student, discovered his condition four years ago while talking with a girlfriend. He was shocked that she could remember what a friend had been wearing a year before. She replied that she could see a picture of it in her mind.
25歲的加拿大學生湯瑪斯．伊貝耶4年前和女友聊天時發現了自己的狀況。他對女友記得友人一年前的穿著感到震驚，女友回答腦海會浮現友人穿著的影像。

“I had no idea what she was talking about,” he said. He was surprised to discover that everyone he knew could summon images to their minds.
「我不曉得她在說甚麼，」他說。他後來發現認識的人腦海都能浮現影像，很訝異。

Like many other subjects, he could count his windows without actually picturing his house.
如同許多其他受試者，他不需浮現影像就能算出自宅有幾扇窗。

“It’s weird and hard to explain,” he said. “I know the facts. I know where the windows are.”
「很怪也很難解釋，」他說。「我知道事實，知道窗戶在哪裡。」

Dr. Zeman is trying to ascertain how common aphantasia is. He has sent the questionnaire to thousands of people and wants to hear from more. He can be reached ata.zeman@exeter.ac.uk.
柴曼想弄清楚aphantasia有多普遍，已對數千人發出問卷，並想聽更多意見，連絡請洽a.zeman@exeter.acu.uk。