There's a good explanation for the phenomenon in the book The Formula: The Universal Law of Success by Albert Laszlo Barabasi.
阿尔伯特·拉兹洛·巴拉巴斯（Albert Laszlo Barabasi）所著的《公式：成功的普遍法则》（the Formula: the Universal Law of Success）一书对这一现象作出了很好的解释。
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According to Barabasi, it's easier and less risky for those in positions of power to choose to hand awards and funding to those who've already been so recognized.