Stylometry has been used to bust open many of the great mysteries surrounding authorship. This statistical sleuthing technique has previously been used to question whether Shakespeare wrote all of his work alone and even hunt down the terrorist “Unabomber” Theodore Kaczynski.
Now, Harvard statistician Mark Glickman and mathematician Jason Brown (both big fans of The Beatles, obviously) have used this technique to weigh in on one of pop culture's big debates: who wrote the song In My Life?
John Lennon and Paul McCartney wrote the majority of The Beatles songs with a handful of notable exceptions. For most of their songs, who wrote which parts is reasonably well documented. However, questions remain over who wrote the music for In My Life, a track from the 1965 album Rubber Soul often cited as one of the “Greatest Songs of All Time”.
Although McCartney always takes credit for writing the song’s music, the statistical analysis of the melody suggests he’s not quite remembering it correctly.
“The probability that In My Life was written by McCartney is .018, which basically means it's pretty convincingly a Lennon song,” Glickman said in a statement.
To unravel this mystery, Glickman and Brown started by breaking down 70 different Beatles songs created between 1962 and 1966 with confirmed authorship. Their approach analyzed the different frequencies, recurring patterns, and structures found in 149 musical features. Using this data, they could then make a fairly good estimation of whether a song was more characteristic of a particular author’s style.
“Think of decomposing a color into its constituent components of red, green and blue with different weights attached. We’re doing the same thing with Beatles songs, though with more than three components,” added Glickman. “In total, our method divides songs into a total of 149 constituent components."
The research looked at other songs from the famous four and confirmed the long-standing observation that Lennon's songs, compared to McCartney’s, feature melodic lines that don’t vary much.
"Consider the Lennon song, Help!" said Glickman. "It basically goes, 'When I was younger, so much younger than today,' where the pitch doesn't change very much. It stays at the same note repeatedly, and only changes in short steps. Whereas with Paul McCartney, you take a song like Michelle, and it goes, 'Michelle, ma belle. Sont les mots qui vont très bien ensemble.' In terms of pitch, it's all over the place."