[多项选择]这可能听起来显得离奇，然而现已完成了一些试验，它们显示，这仍应是正确的解释。在一家医院的婴儿室里，几组新生婴儿被安排听很长时间的每分钟72次的标准速率的心跳录音。每组有9名婴儿，结果发现，当心跳录音停放时，其中一个或更多的婴儿60%的时间在啼哭，但是当心跳录音卜卜响起时，啼哭的时间降到了38%。听心跳声的那几组婴儿的体重的增长也高于另几组婴儿，虽然两者食物的摄取量是相等的。显然，未听心跳声的几组婴儿由于使劲啼哭的行为而消耗了多得多的能量。

参考答案:This may sound far-fetched, but tests have now been carried out which reveal that it is nevertheless the true explanation. Groups of new-born babies in a hospital nursery were exposed for a considerable time to the recorded sound of a heart-beat at a standard rate of GB beats per minute. There were nine babies in each group and it was found that one or more of them was crying for F0 per cent of the time when the sound was not switched on, but that this figure fell to only CH per cent when the heart-beat recording was thumping away. The heart-beat groups also showed a greater weight-gain than the others, although the amount of food taken was the same in both cases. Clearly the beatless groups were burning up a lot more energy as a result of the vigorous actions of their crying.