| By Gretchen Reynolds | |||
張佑生譯 A walk in the park may soothe the mind and, in the process, change the workings of our brains in ways that improve our mental health, according to a new study of the physical effects on the brain of visiting nature. 一個新研究探索親近大自然對大腦造成的生理影響。根據研究，在公園散步可以撫慰心靈，改變我們大腦的運作方式，進而改善我們的心理健康。 Most of us today live in cities and spend far less time outside in green, natural spaces than people did several generations ago. 當今，大多數人都住在城市。與幾代之前的人相比，我們到戶外、在綠地、自然環境的時間少了很多。 City dwellers also have a higher risk for anxiety, depression and other mental illnesses than people living outside urban centers, studies show. Various studies have also found that urban dwellers with little access to green spaces have a higher incidence of psychological problems than people living near parks and that city dwellers who visit natural environments have lower levels of stress hormones immediately afterward than people who have not recently been outside. But just how a visit to a park or other green space might alter mood has been unclear. Does experiencing nature actually change our brains in some way that affects our emotional health? 多項研究顯示，住在城市的人罹患焦慮、憂鬱和其他心理疾病的風險，比住在城外的人高。各種研究提示，與住家附近有公園的人相比，幾乎沒甚麼管道接觸綠地的城市住民，心理出問題的機率更高。而且與最近沒有外出接觸大自然的人相比，造訪過自然環境的城裡人，壓力荷爾蒙濃度在造訪後立即下降。但是去一趟公園或其他綠地如何能夠改變心情，目前還不清楚。造訪大自然真的能給我們的大腦帶來影響情緒健康的變化嗎？  That possibility intrigued Gregory Bratman, a graduate student at Stanford University in California who has been studying the psychological effects of urban living. So for thestudy, which was published in Proceedings of the National Academy of Sciences, Mr. Bratman and his collaborators decided to closely scrutinize what effect a walk might have on a person’s tendency to brood. 此一可能性引起加州史丹佛大學研究生葛萊哥利．布拉特曼的興趣，他一直在研究城市生活造成的心理影響。布拉特曼與研究夥伴決定詳加檢視一次散步對一個人憂思的傾向有何可能的影響，他們並把研究結果發表在《美國國家科學院院刊》上。 Brooding, which is known among cognitive scientists as morbid rumination, is a mental state familiar to most of us, in which we can’t seem to stop chewing over the ways in which things are wrong with ourselves and our lives. It is strongly associated with increased activity in a portion of the brain known as the subgenual prefrontal cortex. 憂思在認知心理學家看來，是一種病態的反芻思考，是大多數人都熟悉的一種心理狀態：個人對自己犯的差錯和生活中遭遇的挫折無法停止鑽牛角尖。此一反芻思考與大腦胼胝體前膝下的前額葉皮層，活動增加的情況密切相關。 Mr. Bratman and his colleagues gathered 38 healthy, adult city dwellers and asked them to complete a questionnaire to determine their normal level of morbid rumination. The researchers checked for brain activity in each volunteer’s subgenual prefrontal cortex, using scans that track blood flow through the brain. Greater blood flow to parts of the brain usually signals more activity in those areas. 布拉特曼和同事招募了38名健康、成年的城市居住者，讓他們填一份問卷，用以判定他們在正常狀態下的病態反芻水準。研究人員用監測腦內血流的掃描器檢查每位志願受測者胼胝體前膝下的前額葉皮層的神經活動。流向大腦某部位的血液越多，該部位的神經活動越活躍。 Then the scientists randomly assigned half of the volunteers to walk for 90 minutes through a parklike portion of the Stanford campus or next to a loud, hectic, multi-lane highway. Immediately after completing their walks, the volunteers repeated both the questionnaire and the brain scan. 接著，科學家們隨機讓半數受測者用90分鐘在史丹佛大學校園內一個宛如公園的區域散步，另一半者則在一條嘈雜喧鬧、多線道的公路旁漫步一樣長的時間。散步結束後，這些人馬上再一次填問卷並做大腦掃描。  As might have been expected, walking along the highway had not soothed people’s minds. But the volunteers who had strolled along the quiet, tree-lined paths showed slight but meaningful improvements in their mental health, according to their scores on the questionnaire. They also had less blood flow to the subgenual prefrontal cortex. That portion of their brains was quieter. 也許你已經想到，在公路邊散步並不能撫慰受測者的心靈。然而，在清靜林蔭小徑散步的受測者，從問卷結果來看，心理健康情況出現些微但有意義的改善。他們流向膝下區前額葉皮層的血液比較少。大腦這一區域的活動也沒那麼劇烈。 These results “strongly suggest that getting out into natural environments” could be an easy and almost immediate way to improve moods for city dwellers, Mr. Bratman said. 布拉特曼說，這些結果「強烈暗示外出親近大自然」，可能是城裡人改善心情的一種簡單且幾乎立刻生效的方法。 But of course many questions remain, he said, including how much time in nature is sufficient or ideal for our mental health, as well as what aspects of the natural world are most soothing. 不過他表示，當然還有很多問題需要解答，包括從心理健康方面考慮，在大自然環境待多久才算足夠或理想呢？大自然環境的哪些方面最具安撫作用？ “There’s a tremendous amount of study that still needs to be done,” Mr. Bratman said. But in the meantime, he pointed out, there is little downside to strolling through the nearest park. 「我們還需要做極大量的研究，」布拉特曼說。但他指出，在此同時，去距離最近的公園逛逛，幾乎沒有壞處。 文章取自 聯合電子報 (如有不妥或侵權，請來信反應，我們會盡速處理與撤除) |