火山爆发、地震、雪崩和滑坡等自然现象会产生空气声、地声（在地内传播）和水声（在水中传播）；此外，自然界中还有潮汐声、雷声、瀑布声、风声、陨石进入大气层的轰声，以及动物发出的声音等，这些非人为活动产生的声音，统称为自然界噪声。
“我们不用学习，而自然地会害怕电击或者巨大的噪声甚至恐怖的脸，这些偏好似乎是天生的，”他告诉LiveScience。
"We don't learn to fear electric shocks or loud noises or even threatening faces, but rather, these preferences seem innate," he told LiveScience.
很显然，被一些科学家归因于异常电活动的超自然现象的确有可能被手机通话和短信息制造的电子噪声所淹没。
Apparently paranormal events, which some scientists put down to unusual electrical activity, could be drowned out by the electronic noise produced by phone calls and text messages.
换句话说，为使长期的自然选择规律发挥作用，必须依赖包含噪声的环境提供触发机制。
In other words, environment containing noise has to be relied on to furnish the triggering mechanism on which the long-term selection rule will operate.
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