You notice at the beginning one-two, At the beginning these chords are holding for four measures or a total of eight beats.

注意在开头，在开始的部分，和弦持续了4小节也就是8拍。

耶鲁公开课 - 聆听音乐课程节选

These are--human attention tends to be sporadic.

人类无法持续保持注意力

耶鲁公开课 - 金融市场课程节选