And if you start to pay attention to this, and you sort of split test.

如果你开始注意这一点，你就会进行拆分测试。

They split test subjects into three groups and asked them not to eat anything for three hours before the experiment.

实验。 他们将测试对象分成三组， 并要求他们在实验前三个小时内不要吃任何东西。