大腦疲勞？到公園走走吧！
報道 2013年04月04日
Brick House Pictures/Getty Images
科學家早就發現，人類大腦保持鎮靜、全神貫注的能力是有限的，這種能力會在持續的噪音和城市生活忙亂嘈雜的逼迫下不堪重負。於是有時候，人們便產生了俗稱“腦疲勞”的狀態。
腦疲勞時，你很難集中精力、容易忘事、精神錯亂——換言之，就是我這個樣子。
不過，蘇格蘭的一項創新性研究告訴人們：只需在綠葉叢生的公園裡逛上一逛，腦疲勞就能夠減輕。
走進綠地——比如公園或種有很多樹的廣場——可以減壓和提高注意力，這並不算是新奇發現。研究者早已論述過綠地具有鎮定效果；比起忙碌的城市街道， 綠地不要求人們有太多的“定向注意力”。自然環境激發出的“軟引力” （soft fascination，一個形容靜思冥想的迷人詞語）幾乎不需要人腦產生任何定向注意，從而大腦可重置被過度使用的精力，緩解腦疲勞。
儘管此理論得到了廣泛認同，但一直難於驗證。以前有研究發現：比起主要生活在鋼筋混凝土建築中的人們，居住在樹多或公園附近的人唾液中皮質醇（一種應激激素）水平較低。注意力有缺陷的兒童，在公園或植物園散步之後容易集中注意力，認知測驗的成績有所提高。更直接的研究是：科學家把志願者帶到實驗室，在他們頭上裝戴檢測電極，然後給他們看自然風景或城市街景的照片。腦電波信號表明，志願者在看自然風景的照片時更加沉穩、鎮靜。
然而實驗室外、行走於城市與公園之間的人們，他們的大腦如何反應還一直無法被監測——或者說直至最近，在一種輕型便攜的腦電圖記錄儀發明出來之前，還沒被監測過。
新研究發表於2013年3月《英國運動醫學雜誌》(The British Journal of Sports Medicine)上。英國愛丁堡的赫瑞瓦特大學(Heriot-Watt University)和愛丁堡大學(University of Edinburgh)的科學家們把這種新型便攜式腦電波儀(EEG, electroencephalo-graph)貼在了12名健康年輕的成年人的頭皮上。電極不露痕迹地藏在一頂貌似普通的針織帽下面，通過無線網絡將腦 波數據傳遞到每個志願者背包里的手提電腦上。
這些研究者以前曾探索過綠地環境對認知的影響。他們讓志願者繞着愛丁堡三個不同地區步行大約1.5英里（約2.4千米）。
志願者在第一個0.5英里內會穿過古老的歷史購物區，那裡有精緻的古典建築，便道上有很多行人，但車流量很小。
接下來的0.5英里，志願者會走進公園一類的地區。
最後一段步行在忙碌的商業區中結束。這裡到處是水泥建築、車水馬龍。
志願者被要求按自己的速度行走，不要着急也別太慢。大多數人在25分鐘之內走完全程。
整個過程中，志願者頭上的便攜式腦電波儀不斷將腦電波的波形反饋到他們背着的手提電腦上。
然後，研究者對輸出信號進行比較，尋找認為與沮喪、定向注意力（他們稱之為“投入度”）、精神喚醒(mental arousal)以及沉靜和鎮定相關的波形。
分析結果證實了綠地能減輕腦疲勞的理論。
當最後走過高度城市化的、繁華的街道——特別是車流量很大的商業區時，志願者的腦電波一致顯示他們的精神處於更加被喚醒的狀態，更留心四周環境，也更沮喪。然而當他們走在公園裡時，腦電波波形變得更為沉靜。
穿行於公園時，步行者平靜多了。
此研究的負責人、赫瑞瓦特大學建築學院教授珍妮·羅伊(Jenney Roe)說，這並不是說他們不關注周圍情況。她解釋道，自然環境仍然會“吸引大腦注意”，不過此類吸引力是“無需花費精力的”，心理學稱之為“無意注意” (involuntary attention)。它佔有一定的注意，但同時也為精神反應留有餘地；可作為由典型市區街道誘發的不停歇注意力的緩和劑。
當然，她的實驗樣本量小，更像是為新型小巧的便攜腦電波儀所做的初步研究，而非眼觀綠色對認知影響的決定性研究。
儘管如此，羅伊教授說，他們的發現還是具有一致性並強有力的。而且，從我們這些生活在城市裡、注意力被迫高度集中的人的角度來說，是很有價值的。羅 伊說，研究結果意味着，現在，你就應當考慮“放下工作休息一會。到綠地走一走，坐一坐；甚至僅僅從你的辦公室窗戶向外眺望綠地也可以。”這可不是什麼沒有效率地浪費時間，羅伊教授適時地讓我們放心：“這樣做很有可能幫你恢復精力，解決腦疲勞，減輕壓力。”
腦疲勞時，你很難集中精力、容易忘事、精神錯亂——換言之，就是我這個樣子。
走進綠地——比如公園或種有很多樹的廣場——可以減壓和提高注意力，這並不算是新奇發現。研究者早已論述過綠地具有鎮定效果；比起忙碌的城市街道， 綠地不要求人們有太多的“定向注意力”。自然環境激發出的“軟引力” （soft fascination，一個形容靜思冥想的迷人詞語）幾乎不需要人腦產生任何定向注意，從而大腦可重置被過度使用的精力，緩解腦疲勞。
儘管此理論得到了廣泛認同，但一直難於驗證。以前有研究發現：比起主要生活在鋼筋混凝土建築中的人們，居住在樹多或公園附近的人唾液中皮質醇（一種應激激素）水平較低。注意力有缺陷的兒童，在公園或植物園散步之後容易集中注意力，認知測驗的成績有所提高。更直接的研究是：科學家把志願者帶到實驗室，在他們頭上裝戴檢測電極，然後給他們看自然風景或城市街景的照片。腦電波信號表明，志願者在看自然風景的照片時更加沉穩、鎮靜。
然而實驗室外、行走於城市與公園之間的人們，他們的大腦如何反應還一直無法被監測——或者說直至最近，在一種輕型便攜的腦電圖記錄儀發明出來之前，還沒被監測過。
新研究發表於2013年3月《英國運動醫學雜誌》(The British Journal of Sports Medicine)上。英國愛丁堡的赫瑞瓦特大學(Heriot-Watt University)和愛丁堡大學(University of Edinburgh)的科學家們把這種新型便攜式腦電波儀(EEG, electroencephalo-graph)貼在了12名健康年輕的成年人的頭皮上。電極不露痕迹地藏在一頂貌似普通的針織帽下面，通過無線網絡將腦 波數據傳遞到每個志願者背包里的手提電腦上。
這些研究者以前曾探索過綠地環境對認知的影響。他們讓志願者繞着愛丁堡三個不同地區步行大約1.5英里（約2.4千米）。
志願者在第一個0.5英里內會穿過古老的歷史購物區，那裡有精緻的古典建築，便道上有很多行人，但車流量很小。
接下來的0.5英里，志願者會走進公園一類的地區。
最後一段步行在忙碌的商業區中結束。這裡到處是水泥建築、車水馬龍。
志願者被要求按自己的速度行走，不要着急也別太慢。大多數人在25分鐘之內走完全程。
整個過程中，志願者頭上的便攜式腦電波儀不斷將腦電波的波形反饋到他們背着的手提電腦上。
然後，研究者對輸出信號進行比較，尋找認為與沮喪、定向注意力（他們稱之為“投入度”）、精神喚醒(mental arousal)以及沉靜和鎮定相關的波形。
分析結果證實了綠地能減輕腦疲勞的理論。
當最後走過高度城市化的、繁華的街道——特別是車流量很大的商業區時，志願者的腦電波一致顯示他們的精神處於更加被喚醒的狀態，更留心四周環境，也更沮喪。然而當他們走在公園裡時，腦電波波形變得更為沉靜。
穿行於公園時，步行者平靜多了。
此研究的負責人、赫瑞瓦特大學建築學院教授珍妮·羅伊(Jenney Roe)說，這並不是說他們不關注周圍情況。她解釋道，自然環境仍然會“吸引大腦注意”，不過此類吸引力是“無需花費精力的”，心理學稱之為“無意注意” (involuntary attention)。它佔有一定的注意，但同時也為精神反應留有餘地；可作為由典型市區街道誘發的不停歇注意力的緩和劑。
當然，她的實驗樣本量小，更像是為新型小巧的便攜腦電波儀所做的初步研究，而非眼觀綠色對認知影響的決定性研究。
儘管如此，羅伊教授說，他們的發現還是具有一致性並強有力的。而且，從我們這些生活在城市裡、注意力被迫高度集中的人的角度來說，是很有價值的。羅 伊說，研究結果意味着，現在，你就應當考慮“放下工作休息一會。到綠地走一走，坐一坐；甚至僅僅從你的辦公室窗戶向外眺望綠地也可以。”這可不是什麼沒有效率地浪費時間，羅伊教授適時地讓我們放心：“這樣做很有可能幫你恢復精力，解決腦疲勞，減輕壓力。”
本文最初發表於2013年3月27日。
翻譯：孫舒雯
翻譯：孫舒雯
Easing Brain Fatigue With a Walk in the Park
April 04, 2013
Brick House Pictures/Getty Images
Scientists have known for some time that the human brain’s ability to
stay calm and focused is limited and can be overwhelmed by the constant
noise and hectic, jangling demands of city living, sometimes resulting
in a condition informally known as brain fatigue.
With brain fatigue, you are easily distracted, forgetful and mentally flighty — or, in other words, me.
But an innovative new study from Scotland suggests that you can ease brain fatigue simply by strolling through a leafy park.
The idea that visiting green spaces like parks or tree-filled plazas lessens stress and improves concentration is not new. Researchers have long theorized that green spaces are calming, requiring less of our so-called directed mental attention than busy, urban streets do. Instead, natural settings invoke “soft fascination,” a beguiling term for quiet contemplation, during which directed attention is barely called upon and the brain can reset those overstretched resources and reduce mental fatigue.
But this theory, while agreeable, has been difficult to put to the test. Previous studies have found that people who live near trees and parks have lower levels of cortisol, a stress hormone, in their saliva than those who live primarily amid concrete, and that children with attention deficits tend to concentrate and perform better on cognitive tests after walking through parks or arboretums. More directly, scientists have brought volunteers into a lab, attached electrodes to their heads and shown them photographs of natural or urban scenes, and found that the brain wave readouts show that the volunteers are more calm and meditative when they view the natural scenes.
But it had not been possible to study the brains of people while they were actually outside, moving through the city and the parks. Or it wasn’t, until the recent development of a lightweight, portable version of the electroencephalogram, a technology that studies brain wave patterns.
For the new study, published this month in The British Journal of Sports Medicine, researchers at Heriot-Watt University in Edinburgh and the University of Edinburgh attached these new, portable EEGs to the scalps of 12 healthy young adults. The electrodes, hidden unobtrusively beneath an ordinary looking fabric cap, sent brain wave readings wirelessly to a laptop carried in a backpack by each volunteer.
The researchers, who had been studying the cognitive impacts of green spaces for some time, then sent each volunteer out on a short walk of about a mile and half that wound through three different sections of Edinburgh.
The first half mile or so took walkers through an older, historic shopping district, with fine, old buildings and plenty of pedestrians on the sidewalk, but only light vehicle traffic.
The walkers then moved onto a path that led through a park-like setting for another half mile.
Finally, they ended their walk strolling through a busy, commercial district, with heavy automobile traffic and concrete buildings.
The walkers had been told to move at their own speed, not to rush or dawdle. Most finished the walk in about 25 minutes.
Throughout that time, the portable EEGs on their heads continued to feed information about brain wave patterns to the laptops they carried.
Afterward, the researchers compared the read-outs, looking for wave patterns that they felt were related to measures of frustration, directed attention (which they called “engagement”), mental arousal and meditativeness or calm.
What they found confirmed the idea that green spaces lessen brain fatigue.
When the volunteers made their way through the urbanized, busy areas, particularly the heavily trafficked commercial district at the end of their walk, their brain wave patterns consistently showed that they were more aroused, attentive and frustrated than when they walked through the parkland, where brain-wave readings became more meditative.
While traveling through the park, the walkers were mentally quieter.
Which is not to say that they weren’t paying attention, said Jenny Roe, a professor in the School of the Built Environment at Heriot-Watt University, who oversaw the study. “Natural environments still engage” the brain, she said, but the attention demanded “is effortless. It’s called involuntary attention in psychology. It holds our attention while at the same time allowing scope for reflection,” and providing a palliative to the nonstop attentional demands of typical, city streets.
Of course, her study was small, more of a pilot study of the nifty new, portable EEG technology than a definitive examination of the cognitive effects of seeing green.
But even so, she said, the findings were consistent and strong and, from the viewpoint of those of us over-engaged in attention-hogging urban lives, valuable. The study suggests that, right about now, you should consider “taking a break from work,” Dr. Roe said, and “going for a walk in a green space or just sitting, or even viewing green spaces from your office window.” This is not unproductive lollygagging, Dr. Roe helpfully assured us. “It is likely to have a restorative effect and help with attention fatigue and stress recovery.”
With brain fatigue, you are easily distracted, forgetful and mentally flighty — or, in other words, me.
The idea that visiting green spaces like parks or tree-filled plazas lessens stress and improves concentration is not new. Researchers have long theorized that green spaces are calming, requiring less of our so-called directed mental attention than busy, urban streets do. Instead, natural settings invoke “soft fascination,” a beguiling term for quiet contemplation, during which directed attention is barely called upon and the brain can reset those overstretched resources and reduce mental fatigue.
But this theory, while agreeable, has been difficult to put to the test. Previous studies have found that people who live near trees and parks have lower levels of cortisol, a stress hormone, in their saliva than those who live primarily amid concrete, and that children with attention deficits tend to concentrate and perform better on cognitive tests after walking through parks or arboretums. More directly, scientists have brought volunteers into a lab, attached electrodes to their heads and shown them photographs of natural or urban scenes, and found that the brain wave readouts show that the volunteers are more calm and meditative when they view the natural scenes.
But it had not been possible to study the brains of people while they were actually outside, moving through the city and the parks. Or it wasn’t, until the recent development of a lightweight, portable version of the electroencephalogram, a technology that studies brain wave patterns.
For the new study, published this month in The British Journal of Sports Medicine, researchers at Heriot-Watt University in Edinburgh and the University of Edinburgh attached these new, portable EEGs to the scalps of 12 healthy young adults. The electrodes, hidden unobtrusively beneath an ordinary looking fabric cap, sent brain wave readings wirelessly to a laptop carried in a backpack by each volunteer.
The researchers, who had been studying the cognitive impacts of green spaces for some time, then sent each volunteer out on a short walk of about a mile and half that wound through three different sections of Edinburgh.
The first half mile or so took walkers through an older, historic shopping district, with fine, old buildings and plenty of pedestrians on the sidewalk, but only light vehicle traffic.
The walkers then moved onto a path that led through a park-like setting for another half mile.
Finally, they ended their walk strolling through a busy, commercial district, with heavy automobile traffic and concrete buildings.
The walkers had been told to move at their own speed, not to rush or dawdle. Most finished the walk in about 25 minutes.
Throughout that time, the portable EEGs on their heads continued to feed information about brain wave patterns to the laptops they carried.
Afterward, the researchers compared the read-outs, looking for wave patterns that they felt were related to measures of frustration, directed attention (which they called “engagement”), mental arousal and meditativeness or calm.
What they found confirmed the idea that green spaces lessen brain fatigue.
When the volunteers made their way through the urbanized, busy areas, particularly the heavily trafficked commercial district at the end of their walk, their brain wave patterns consistently showed that they were more aroused, attentive and frustrated than when they walked through the parkland, where brain-wave readings became more meditative.
While traveling through the park, the walkers were mentally quieter.
Which is not to say that they weren’t paying attention, said Jenny Roe, a professor in the School of the Built Environment at Heriot-Watt University, who oversaw the study. “Natural environments still engage” the brain, she said, but the attention demanded “is effortless. It’s called involuntary attention in psychology. It holds our attention while at the same time allowing scope for reflection,” and providing a palliative to the nonstop attentional demands of typical, city streets.
Of course, her study was small, more of a pilot study of the nifty new, portable EEG technology than a definitive examination of the cognitive effects of seeing green.
But even so, she said, the findings were consistent and strong and, from the viewpoint of those of us over-engaged in attention-hogging urban lives, valuable. The study suggests that, right about now, you should consider “taking a break from work,” Dr. Roe said, and “going for a walk in a green space or just sitting, or even viewing green spaces from your office window.” This is not unproductive lollygagging, Dr. Roe helpfully assured us. “It is likely to have a restorative effect and help with attention fatigue and stress recovery.”
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