The author claims that it is the increased levels of melatonin before birth that cause shyness during infancy and later life, through a research and some conclusion of what effect the shyness.

• 首先，据个人所知，婴儿或多或少对陌生环境会有不同程度的紧张，作者没有提供说明这些婴儿比其他婴儿更紧张。