In the 1990s, the attention span of moviegoers was first measured into a series of waves using a mathematical trick called a Fourier transform. It was observed that particular length of attention spans in the viewers often recurred at regular intervals. Now, this property is known as a 1/f fluctuation, or 'pink noise," reports New Scientist. Cutting has measured the duration of every shot in 150 high-grossing Hollywood movies in various genres released between 1935 and 2005.
He found that later films were more likely to obey the 1/f law than earlier ones. However, Cutting insists that directors are not deliberately using mathematics to make movies. He thinks films that happen to be edited in this way, which are often more gripping, has inspired other filmmakers to follow suit. It also explains the reason most recent films tend to follow 1/f.