SSS(分享有字幕) 150729 Scream Acoustics

SSS(分享有字幕) 150729 Scream Acoustics

2015-08-08    01'47''

主播: 真水无香看世界

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介绍:
Got your attention? Thought so. But what is it about a piercing shriek that really turns our heads? It’s what it does to our brains. The acoustical properties of the human scream poke涌出 at the neural circuits that control fear. That’s according to a study in the journal Current Biology. Our every waking moment is filled with noise, from planes flying overhead to various creatures scrambling爬 underfoot. But a heartfelt衷心的 cry can cut through穿透 all that. So what’s so special about the sound of a screech尖叫? To find out, researchers prepared a sampler of screams from YouTube videos, popular films and excited volunteers.If that screech sounded familiar, that’s because it’s the famous Wilhelm Scream, a stock sound effect heard in everything from Bugs Bunny to Star Wars. The scientists analyzed the acoustical characteristics of the various screams. And they found these alarming sounds are not only loud, they’re particularly rough. That is, they rapidly change in frequency. Normal speech is relatively smooth, with frequencies ranging only between four and five Hertz赫兹, or cycles per second. But a shriek尖叫 can swiftly fluctuate between 30 and 150 Hertz—a range that can make your hair stand on end. When the researchers asked people to rate how frightening screams were, they found that more roughness高低不平 meant more terrifying可怕的. And increasing roughness of the sound corresponded to greater activation激活 of the fear center of the brain. Only one other noise scored as high as screams in terms of roughness高低不平. Which, ironically, is enough to make you [scream sound]. —Karen Hopkin