This doubleness may easily make us poor neighbors and friends sometimes .

但有时这双重人格很容易使别人难于和我们作邻居，交朋友了。

In his influential 1974 book " the inner game of tennis , " author timothy gallwey applied the notion of doubleness to the tennis player , describing how each self hinders or enhances performance .

作家蒂莫西葛维在他1974年出版的一部颇具影响力的著作《网球的内心竞赛》中赋予了网球选手双重人格，书中描述了选手的另一人格如何妨碍或者提升他的表现。