Why we need silence

为什么我们需要安静

A. Humans are finely attuned to noise, and for good reason. From an evolutionary perspective, sounds give us vital information, helping us navigate the world and avoid danger. To help ensure loud or unexpected noises get the attention they deserve, our internal chemistry alters in response to them. Our blood pressure goes up, muscles tense and glands release hormones that prepare us for fight or flight. In the short term, this is a good thing. When we are exposed to too much noise over the long term, however, those responses can lead to a multitude of health issues, from sleep disturbance to even cardiovascular disease.

人类对噪音有着敏锐的感知，这是有充分理由的。从进化的角度来看，声音为我们提供了至关重要的信息，帮助我们在世界中辨明方向并躲避危险。为确保响亮或意外的声响能得到应有的关注，我们体内的化学机制会随之发生变化：血压升高，肌肉紧张，腺体分泌出为"战斗或逃跑"做准备的激素。短期而言，这是一件好事。然而，当我们长期暴露于过多噪音之中，这些反应便可能引发多种健康问题，从睡眠紊乱乃至心血管疾病皆有可能。

B. The World Health Organization has recently designated excessive noise as an 'underestimated threat' to public health, and has said that people living in cities such as Mumbai, Tokyo and Buenos Aires are being exposed to far more than the recommended 40 decibels of noise at night. A report from the European Environment Agency concluded that noise was an ongoing and widespread issue in Europe, with at least 1 in 5 people consistently exposed to levels considered harmful to health. 'There are no "earlids" that can protect your brain from noise,' says Nick Antonio, an acoustic consultant who has contributed to the British and international standards for noise.

世界卫生组织近来将过量噪音列为对公共健康"被低估的威胁"，并指出居住在孟买、东京和布宜诺斯艾利斯等城市的居民，夜间所承受的噪音水平远超建议的40分贝标准。欧洲环境署的一份报告得出结论，认为噪音在欧洲是一个持续且普遍存在的问题，至少五分之一的人持续暴露于被认为对健康有害的噪音水平之中。"并不存在能保护你的大脑免受噪音侵扰的'耳盖'，"曾参与制定英国及国际噪音标准的声学顾问尼克·安东尼奥如是说。

C. The good news is that several cities have been working to turn the volume down. One of the first to do so was London. 'By providing recommendations for quieter buses, reducing noise from roads and also controlling noise from aircraft, they were able to make the city quieter,' says Antonio. Other cities have introduced noise-reducing road coatings, for instance, alongside greenery that muffles sound. Some solutions are more specific: Washington DC's ban on petrol-powered leaf blowers came into effect recently, while in New York City, legislation has been approved to fine people who modify their vehicles to make them noisier. 'People are seeing the benefits of these more quiet environments in their cities,' Antonio says. 'I expect we will see much more of this in the future.'

好消息是，已有多座城市着手将噪音降低。伦敦便是最早采取此类行动的城市之一。安东尼奥表示："通过提出建议以推广更安静的公共汽车、降低道路噪音以及控制飞机噪音，伦敦得以让城市变得更加安静。"其他城市也引入了诸如降噪路面材料，并搭配能够消减声音的绿化植被等举措。还有一些解决方案则更为具体：华盛顿特区近来已开始施行对汽油动力吹叶机的禁令，而纽约市则已通过立法，对改装车辆使其噪音更大的人士处以罚款。安东尼奥说："人们已经看到城市环境变得更安静所带来的好处。我预期未来此类举措会更加普遍。"

D. Researchers are also seeking to understand what aspects of silent experiences are most beneficial to our health. One of the best-researched is the flotation tank: a lightproof, soundproof tank of salt water in which a person floats as a form of deep relaxation. While some people experience altered perception in the tanks, involving subtle humming sounds and visual effects, these effects are benign and do not detract from the benefits of the experience, says Justin Feinstein, a clinical neuropsychologist. 'When you don't have external sensory stimuli coming in, the brain tries to fill the void to make sense of this dark and silent world,' he explains. 'In these tanks, some people can even hear the sound of their eyes blinking,' says Feinstein. 'But it is the ability to focus on the breath that helps people reach a relaxed or meditative state.'

研究人员还在探索静默体验中哪些方面对我们的健康最为有益。其中研究最为充分的便是漂浮舱：一种不透光、隔音的盐水舱，人可漂浮其中，以达到深度放松的效果。临床神经心理学家贾斯汀·费恩斯坦表示，尽管有些人在舱内会经历知觉上的改变，比如出现细微的嗡鸣声及视觉效应，但这些效应是良性的，并不会削弱这种体验所带来的益处。他解释道："当外部感官刺激缺失时，大脑会试图填补这片空白，以理解这个黑暗而寂静的世界。"费恩斯坦说："在这些舱内，有些人甚至能听到自己眨眼的声音。但真正帮助人们达到放松或冥想状态的，是专注于呼吸的能力。"

E. To further explore flotation tanks as a therapeutic tool, Feinstein and his colleagues recruited 50 people with a variety of conditions related to stress and had them answer a questionnaire prior to and following a flotation session. Participants reported decreases in muscle tension, pain and symptoms of their conditions after a single, 1-hour float, alongside an increase in feelings of relaxation and overall wellbeing. Less is known about what effects sensory deprivation can have on the brain. To investigate, Feinstein's team had 48 people participate in either three 90-minute float sessions or three 90-minute periods of relaxing on a chair which reclined. Participants had their brains scanned using functional magnetic resonance imaging at the beginning and end of the trial. Float sessions uniquely decreased activity in the default mode network (DMN), a collection of brain regions commonly linked with depression. Feinstein says it is an exciting finding, because flotation tanks seem to offer a way of 'resetting' our nervous system to prevent it from getting out of balance.

为进一步探究漂浮舱作为治疗工具的效用，费恩斯坦及其同事招募了50名患有各类压力相关病症的人士，并让他们在漂浮体验前后分别填写问卷。参与者反映，在经历单次一小时的漂浮后，肌肉紧张、疼痛及其病症的症状均有所减轻，同时放松感与整体幸福感有所提升。至于感官剥夺对大脑究竟有何影响，目前所知则较少。为探究这一问题，费恩斯坦的团队让48名参与者分别参加三次90分钟的漂浮体验，或三次90分钟在可倾斜座椅上的放松体验。参与者在试验开始与结束时均接受了功能性磁共振成像脑部扫描。结果显示，唯有漂浮体验能降低默认模式网络（DMN）的活动——这是一组通常与抑郁症相关联的脑区。费恩斯坦表示，这是一项令人振奋的发现，因为漂浮舱似乎提供了一种"重置"我们神经系统的方式，以防止其失衡。

F. Neurobiologist Tal Dotan Ben-Soussan is also an advocate of silence as a therapy. 'When we find ways to be quiet, we are not only quiet in our environment, but quiet in our inner selves,' she explains. 'This allows us to be more aware of what is happening around us and what the situation may require from us so we can provide a more adequate response.' Not everyone will benefit from silence to the same extent, but Ben-Soussan says one characteristic is key: the person must need to want to engage in the experience. 'We see from animal models and human studies that volition and intentionality is important,' she says. 'When people do not want silence, it can be very distressing.'

神经生物学家塔尔·多坦·本-苏桑同样是将静默作为一种疗法的倡导者。她解释道："当我们找到使自己安静下来的方式时，我们不仅是在环境上变得安静，内心也会随之安静下来。这使我们能够更加敏锐地察觉周围正在发生的事，以及当下情境对我们的要求，从而做出更恰当的回应。"并非每个人都能从静默中获得同等程度的益处，但本-苏桑指出，其中一项特质至关重要：当事人必须真正想要投入这种体验。她说："从动物模型与人类研究中我们可以看到，意愿与主动性十分重要。当人们并不想要静默时，这种体验可能会令人非常痛苦。"

G. Eric Pfeifer, a psychotherapy researcher, also concedes that some people may not benefit from silence, particularly those who are in a heightened state of stress. 'People in these states may not be able to relax or calm down in a silent condition,' he says. Professional guidance can be useful, he adds, allowing people to approach silence slowly so that they can gradually enjoy the benefits. And Pfeifer is convinced that silence is more attainable in everyday life than people think. First, complete silence isn't necessary. In a recent study, he found that participants reported more relaxation and less boredom when they sat quietly in an outdoor garden compared with a completely silent room. Second, Pfeifer believes we don't need a lot of silence to gain benefits. 'You don't need to spend hours in silence,' he says. 'It is likely better to have more frequency of silence for a few minutes at a time than a longer period of silence only once a week. Just finding those places in your daily life where you can find some silence can make a big difference.'

心理治疗研究者埃里克·普菲弗也承认，有些人或许无法从静默中获益，尤其是那些处于高度紧张应激状态下的人。他说："处于这类状态下的人，可能无法在静默的环境中放松或平静下来。"他还补充道，专业指导可能会有所助益，能让人们逐步、缓慢地接触静默，从而渐渐享受到其中的益处。此外，普菲弗坚信，静默在日常生活中比人们所想的更容易获得。首先，完全的静默并非必要。在一项近期研究中，他发现，相较于完全安静的房间，参与者在室外花园中静坐时报告的放松感更强、无聊感更少。其次，普菲弗认为，获益并不需要大量的静默。他说："你不需要花费数小时处于静默之中。比起每周只有一次较长时间的静默，更频繁地、每次几分钟的静默，效果可能更好。仅仅是在日常生活中找到那些能让你获得片刻静默的场所，便足以带来巨大的不同。"