题目内容：

    What’s in the scream? It is thought that the sound of a scream has an acoustic(听觉的) signature - an acoustic DNA that tells the listener’s ear that they are hearing a scream, even if it is not. “The scream may initially run to scare the attacking predator(捕食者). The study of screaming has the potential to help us understand the evolution of emotional communication,” says Jay Schwartz of Emory university.

Jay Schwartz and his colleagues asked 181 volunteers to listen to 75 sounds that included laughter, crying, moans, groans, and yells from acted origins, like television or movies, and more natural sources, such as a YouTube video of a child opening a present and screaming in delight. The listeners indicated whether or not each sound was something they considered a scream. “We did not provide any type of definition for a scream because we were trying to get at what is it in people’s minds that distinguishes a scream,” says Schwartz, who presented his work at a meeting of the Acoustical Society of America on 14 May.

When they analyzed the sound files, they found that the ones listed as screams had acoustic similarities. People were more likely to consider a sound a scream if it was higher in pitch(音高), and had a varied change in pitch, first moving up and then down at the end.

Rapid changes in amplitude - perceived as a rough, gravelly quality - also tended to be classified as screams more than sounds with a smoother tone. This sound was classified as a scream by 64 percent of the listeners. Surprisingly, a recording of a whistle was categorized as a scream by 70 percent of the participants. “It was because the whistle exhibited a lot of the acoustic qualities that we found to be associated with a scream, including high pitch and roughness,” says Schwartz.

1.What was the scream used for in the beginning?

A.Frightening the enemies. B.Sharing the different acoustic DNA.

C.Attracting the volunteers D.Understanding the emotional evolution.

2.What does Jay Schwartz’s research aim to understand?

A.Where people would scream. B.How people judged the scream.

C.Why people would scream. D.What was the best scream.

3.What did the screams have in common?

A.Higher pitch. B.A peaceful mind.

C.Natural origins. D.Different functions.

4.Why was the whistle considered a scream by most listeners?

A.It had the smoother tone. B.It showed some roughness.

C.It made listeners satisfied. D.It did great harm to people.