Question

    You’re walking down a quiet street and suddenly you hear some footsteps. Undoubtedly, it means that there’s someone around. But have you ever wondered why it occurs to us that it’s someone else’s footsteps, not ours?

According to a new study published in the journal Nature in September, this phenomenon arises from a function in our brain to ignore the noise we make ourselves.

In order to explore how our brain does this, a group of scientists carried out an experiment with mice at Duke University. The research entered on an intuition-that we are usually unaware of the sound of our own footsteps-as a vehicle for understanding larger neural phenomena; how this behavior reveals the ability to monitor, recognize, and remember the sound of one’s own movements in relation to those of their larger environments.

In the experiment, research controlled the sounds of a group of mice could hear, reported Science Daily. During the first several days, the mice would hear the same sound each time they took a step. This was just like “running on a tiny piano with each key playing exactly the same note”, senior study author Richard Mooney, a professor of neurobiology at Duke University, told Live Science.

Scientists found that their auditory cortex (听觉皮层) – the area of the brain that processes sound –became active at first but decreased its response to the sound after two or three minutes when the mice became familiar with it.

“ It’s almost like they were wearing special headphones that could filter (过滤) out the sound of their own movements.” David Schneider, an assistant professor at the Center for Neutral Science at New York University, told HuffPost.

But once the sound changed, their auditory cortex became active again. This suggests that the “sensory filter” in a mouse’s brain could help it detect new sounds or abnormal noise in the environment easily after tuning out familiar sounds.

“For mice, this is really important,” said Schneider. “They are prey animals, so they really need to be able to listen for a cat creeping up on them, even when they’re walking and making noise.

Being able to ignore the sounds of one’s own movements is likely important for humans as well. But the ability to predict the sounds of our own actions is also important for more complex human behaviors such as speaking or playing an instrument.

“When we learn to speak or to play music, we predict what sounds we are going to hear – such as when we prepare to strike keys on a piano – and we compare this to what we actually hear, “explains Schneider. “We use mismatches between expectation and experience to change how we play – and we get better over time because our brain is trying to minimize these errors.”

1.What can be discovered about mice in the experiment?

A.Their brain responds inactively to the familiar sounds

B.They are able to detect sounds other animals don’t notice.

C.They cannot identify different sounds except their own footsteps.

D.Different areas of their brain are responsible for different sounds.

2.What’s the function of the sensory filter?

A.Ignoring the sounds made by our companions.

B.Getting used to abnormal or unfamiliar sounds.

C.Identifying the sounds from a larger environment.

D.Being sensitive to the sounds of our own movement.

3.Why can a good symphony conductor immediately recognize it when a wrong note is played?

A.He has the ability to match the wrong note with the instrument player.

B.He has an intuition that he should ignore the sound of his own movement.

C.He has a low expectation and knows where players are likely to make errors.

D.He has a good prediction of how each note should be played in the orchestra.

4.What can be inferred from the passage?

A.Noise-filtering ability ensures us a quiet and undisturbed environment.

B.The ability to ignore familiar noises helps to detect potential dangers.

C.The activeness of auditory cortex determines our activity performance.

D.Sound-predicting ability seems not so important for humans as for animals.

Answer

1.A

2.C

3.D

4.B

【解析】

这是一篇说明文。文章主要说明了根据9月份发表在《自然》杂志上的一项新研究表明人类拥有忽视熟悉的噪音的能力，即忽视我们自己发出的噪音，文章说明了得出这一结论的实验过程，实验结果说明能够忽视自己动作的声音对人类来说很重要。

1.细节理解题。根据文章倒数第四段中This suggests that the “sensory filter” in a mouse’s brain could help it detect new sounds or abnormal noise in the environment easily after tuning out familiar sounds.（这表明，老鼠大脑中的“感觉过滤器”可以帮助它在排除熟悉的声音后，更容易地检测到环境中的新声音或异常噪音）。由此可知，老鼠的大脑对熟悉的声音反应迟钝。结合选项，故选A。

2.推理判断题。根据文章倒数第五段中It’s almost like they were wearing special headphones that could filter (过滤) out the sound of their own movements.（这就像他们戴着特殊的耳机，可以过滤掉自己运动的声音）。由此可以推断出，这种过滤器可以识别来自大环境中的声音。结合选项，故选C。

3.推理判断题。根据文章倒数第二段中Being able to ignore the sounds of one’s own movements is likely important for humans as well. But the ability to predict the sounds of our own actions is also important for more complex human behaviors such as speaking or playing an instrument.（能够忽略自己动作的声音对人类来说可能也很重要。但是，预测我们自己行动的声音的能力，对于更复杂的人类行为，比如说话或演奏乐器也很重要。）由此可以推知，一个好的交响乐指挥家在一个错误的音符被演奏时，能立即识别它，因为他能够预测出每个音符在管弦乐队中应该如何演奏。结合选项，故选D。

4.推理判断题。根据文章第一段中You’re walking down a quiet street and suddenly you hear some footsteps. Undoubtedly, it means that there’s someone around. But have you ever wondered why it occurs to us that it’s someone else’s footsteps, not ours?（你走在一条安静的街道上，突然听到一些脚步声。毫无疑问，这意味着周围有人。但你有没有想过，为什么我们会想到这是别人的脚步，而不是我们的?）由此可以判断出，如果人类有忽视熟悉噪音的能力，有助于发现潜在危险。结合选项，故选B。