世界上有不少人相信鬼的存在。其实，大多数“见鬼”经历都是可以用科学来解释的。你所害怕的“鬼”，往往只是一种错觉。

1. ELECTROMAGNETIC FIELDS 电磁场

For decades, a Canadian neuroscientist named Michael Persinger studied the effects of electromagnetic fields on people's perceptions of ghosts, hypothesizing that pulsed magnetic fields, imperceptible on a conscious level, can make people feel as if there is a “presence” in the room with them by causing unusual activity patterns in the brain's temporal lobes. Persinger studied people in his lab wearing a so-called “God Helmet,” finding that certain patterns of weak magnetic fields over someone's head for 15 to 30 minutes can create the perception that there's an invisible presence in the room.

加拿大神经学家迈克尔·波辛格花了几十年研究电磁场对于“见鬼”的影响后做出了一个假设，那就是人在意识层面察觉不到的脉冲磁场可以通过引发大脑颞叶的异常活动，让人们感觉屋里有“鬼”。波辛格在实验室里让人们戴上所谓的“上帝头盔”，并通过研究发现，人的大脑受到特定模式的弱磁场影响15到30分钟后，就会产生屋里有鬼的感觉。

2. INFRASOUND 次声波

Infrasound is sound at levels so low humans can't hear it (though other animals, like elephants, can). Low frequency vibrations can cause distinct physiological discomfort. Scientists studying the effects of wind turbines and traffic noise near residences have found that low-frequency noise can cause disorientation, feelings of panic, changes in heart rate and blood pressure, and other effects that could easily be associated with being visited by a ghost.

次声波指的是人类无法听到的频率过低的声音（不过其他一些动物能听到，比如大象）。低频率的声波会引发生理上的明显不适。科学家研究了居民住宅附近的风力涡轮机和交通噪音的影响，结果发现，低频率噪音会引发定向障碍、恐慌感、心率和血压波动以及其他容易和见鬼联系在一起的症状。

For instance, in a 1998 paper on natural causes of hauntings, engineer Vic Tandy described working for a medical equipment manufacturer, whose labs included a reportedly haunted room. Whenever Tandy worked in this particular lab, he felt depressed and uncomfortable, often hearing and seeing odd things—including an apparition that definitely looked like a ghost. Eventually, he discovered that the room was home to a 19 Hz standing wave coming from a fan, which was sending out the inaudible vibrations that caused the disorienting effects. Further studies also show links between infrasound and bizarre sensations like getting chills down the spine or feeling uneasy.

举个例子，在1998年的一篇关于“见鬼”自然成因的论文中，工程师维克·坦迪描述了自己在一家医疗设备生产商工作的经历，据说这个生产商的实验室“闹鬼”。每次坦迪在这个“闹鬼”的实验室里工作时，都会感到压抑和不适，还经常听到、看到奇怪的东西，包括一个看起来非常像鬼的幻影。最后，他发现这个房间里有一个产生19赫兹驻波的风扇，这种听不见的声波振动会引发定向障碍。进一步的研究还表明，次声波与后背发凉或惴惴不安的怪异感觉也有关系。

3. MOLD 霉菌

Shane Rogers, an engineering professor at Clarkson University, spent months touring reportedly haunted locations looking for not-so-paranormal activity: mold growth. Preliminary research indicated that some molds can cause symptoms that sound pretty ghostly—like irrational fear and dementia. “I've watched a lot of ghost shows,” he told Mental Floss in 2015.

克拉克森大学的工程学教授谢恩·罗杰斯花了数个月到各个“闹鬼”之地寻找一种并非超自然的现象：霉菌生长。先前的研究显示，一些霉菌会引发类似灵异的症状，比如无理性的恐惧和痴呆。他在2015年告诉Mental Floss网站说：“我看到了不少闹鬼现象。”

4. CARBON MONOXIDE POISONING 一氧化碳中毒

In 1921, a doctor named W.H. Wilmer published an odd story about a haunted house in the American Journal of Ophthalmology. The family who lived in this haunted residence, called the H family in the medical literature, began experiencing weird phenomena when they moved into an old house—hearing furniture moving around and strange voices in the night, feeling the presence of invisible specters. They reported being held down in bed by ghosts, feeling weak, and more. As it turned out, a faulty furnace was filling their house with carbon monoxide, causing aural and visual hallucinations. The furnace was fixed, and the H family went back to their lives, sans ghosts.

1921年，一位名叫W·H·威尔默的医生在《美国眼科学杂志》上发表了一篇关于“鬼屋”的奇谈。住在鬼屋里的一家人在这本医学杂志中被称为H家，他们搬进这座老房子后就开始怪事连连。他们在夜里听到家具移动和奇怪的声音，感觉隐形的鬼魂在身边游荡。他们还报告称自己被“鬼压床”，感觉虚弱无力，诸如此类。结果发现，因为火炉出了故障，家里充满了一氧化碳气体，从而引发了听觉和视觉上的幻觉。后来炉子修好了，H家又回到了没有鬼的正常生活。