<閱讀測驗>Screaming is one of the primal responses humans share with other animals. Conventional thinking suggests that what sets a scream apart from other sounds is its loudness or high pitch. However, many sounds that are loud and high-pitched do not raise goose bumps like screams can. To find out what makes human screams unique, neuroscientist Luc Arnal and his team examined a bank of sounds containing sentences spoken or screamed by 19 adults. The result shows screams and screamed sentences had a quality called “roughness,” which refers to how fast a sound changes in loudness. While normal speech sounds only have slight differences in loudness-between 4 and 5 Hz, screams can switch very fast, varying between 30 and 150 Hz, thus perceived as being rough and unpleasant. Arnal’s team asked 20 subjects to judge screams as neutral or fearful, and found that the scariest almost always corresponded with roughness. The team then studied how the human brain responds to roughness using fMRI brain scanners. As expected, after hearing a scream, activity increased in the brain’s auditory centers where sound coming into the ears is processed. But the scans also lit up in the amygdala, the brain’s fear center. The amygdala is the area that regulates our emotional and physiological response to danger. When a threat is detected, our adrenaline rises, and our body prepares to react to danger. The study discovered that screams have a similar influence on our body. It also found that roughness isn’t heard when we speak naturally, regardless of the language we use, but it is prevalent in artificial sounds. The most aggravating alarm clocks, car horns, and fire alarms possess high degrees of roughness. One potential application for this research might be to add roughness to alarm sounds to make them more effective, the same way a bad smell is added to natural gas to make it easily detectable. Warning sounds could also be added to electric cars, which are particularly silent, so they can be efficiently detected by pedestrians. 48. What is the first paragraph mainly about? (A) Different types of screams. (B) Human sounds and animal cries. (C) Specific features of screams. (D) Sound changes and goose bumps.
