In general, it seems reasonable to suppose that we should prefer peace and quiet to noise. And yet most of us have had the experience of having to adjust to sleeping in the mountains or the countryside because it was initially “too quiet”, an experience that suggests that humans are capable of adapting to a wide range of noise levels. Research supports this view. For example, Glass and Singer (1972) exposed people to short bursts of very loud noise and then measured their ability to work out problems and their physiological reactions to the noise. The noise was quite disruptive at first, but after about four minutes the subjects were doing just as well on their tasks as control subjects who were not exposed to noise. Their physiological reactions also declined quickly to the same levels as those of the control subjects.
But there are limits to adaptation and loud noise becomes more troublesome if the person is required to concentrate on more than one task. For example, high noise levels affect the performance of subjects who were required to monitor three dials at a time, a task not unlike that of a plane pilot or an air-traffic controller. Similarly, noise did not affect a subject’s ability to track a moving line with a steering wheel, but it did affect the subject’s ability to repeat numbers while tracking (Finkelm and Glass 1970).
Probably the most significant finding from the research on noise is that its predictability is more important than how loud it is. We are much more able to “tune out” long-lasing background noise, even if it is quite loud, than to work under circumstances with unexpected disturbance of noise. In Glass and Singer’s study, in which subjects were exposed to bursts of noise as they worked on a task, some subjects heard loud bursts and others heard soft bursts. For some subjects, the bursts were spaced exactly one minute apart (predictable noise); others heard the some amount of noise overall, but the bursts occurred at random intervals (unpredictable noise). Subjects reported finding the predictable and unpredictable noise equally annoying, and all subjects performed at about the same level during the noise portion of the experiment. But the different noise conditions had quite different after-effects when the subjects were required to proofread written material under conditions of no noise. The study shows that the unpredictable noise produced more errors in the later proofreading task than predictable noise; and soft unpredictable noise actually produced slightly more errors on this task than the loud predictable noise.
Apparently, unpredictable noise produces more fatigue than predictable noise, but it takes a while for this fatigue to take its toll on performance.
When talking about people’s difficulty in sleeping in the mountains, what can be inferred in the passage?

A．They usually do not prefer peace and quiet to noise.

B．They may be exposed to short bursts of very strange sounds.

C．They prefer to hear a certain amount of noise while they sleep.

D．They may not have adapted to a higher noise level in the city.

What did Glass and Singer find in their noise experiment?

A．Problem-solving is much easier under quiet conditions.

B．Physiological reactions prevent the ability to work.

C．Bursts of noise hardly disturb problem-solving in the long term.

D．The physiological reactions of the control subjects declined quickly.

Researchers discovered that high noise levels are not likely to affect the __________.

A．successful performance of a single task

B．tasks of pilots or air traffic controllers

C．ability to repeat numbers while tracking moving lines

D．ability to monitor three dials at once

What does “take its toll on performance” in the passage probably mean?

A．Destroy the performance completely.

B．Have a negative effect on the performance.

C．Improve the performance greatly.

D．Have a positive influence on the performance.