Song Modality: Trends Over Time
Is there a noteworthy difference in word usage patterns over time?
Chronologically, the key date to look for is 1964, since The Beatles began their first US tour -- commonly known as "The British Invasion" -- with a concert in New York City on February 7th of that year. This tour made them a phenomenal success; it also represented their exposure to a new music market that, while it clearly loved them, could have different tastes. Their songwriting, and their choice of cover songs to record, may have responded to some extent to that market. Did it, and if so, to what extent?
The graph above is visually confusing, yet it is full of data. Even a brief glance will show that the "warm" colors (red, orange, yellow) are most represented in the upper half of the spectrum, while the cooler colors (especially cyan, blue, purple, and black) are more heavily represented in the lower half.
What does this mean? Let's break it down. We know that the left has high scores (focus on fewer common words, repeated often) and the right has low scores (focus on uncommon words, or words used fewer times per song, so more linguistical variety); so we can cut out the height element that is used to indicate that. We can also disaggregate the bars by year, and set the background to light grey so the blue background of the website is eliminated as a visually confusing factor.
Vertically disaggregated this way into a kind of lyrical spectroscopy, we can see some trends over time emerging.
1960-1962 (red): While there are few songs, and some occur further down the spectrum, there is a clear cluster towards the high end of the scale, emphasizing use of common words. This may represent an early and less linguistically ambitious or sophisticated phase of their songwriting.
1963 (orange): This was their single most productive year of their recording career. There are definitely more songs to the bottom of the scale, indicating more willingness to use uncommon words, suggesting a moving on from writing simplistic ditties; but the center of gravity is still to the left (high end) of the scale.
1964 (yellow): The year of the British Invasion. The center of gravity contracts sharply towards the higher end of the scale, indicating a move back away from uncommon words. This may represent a commercial, market-driven response to an American musical consumer assumed to be less linguistically sophisticated, more interested in simple, catchy lyrics.
1965 (green): The year following the British Invasion. Visually, the bars pull further in towards the center than in either 1964 or 1963, though there is a returning willingness to flirt with the bottom end of the scale. Sometimes when a band has been phenomenally successful, they have more ability to push back against a record label's insistence for maximally marketable music and indulge their artistic ambitions; they have much less to prove at that point.
1966 (cyan): This certainly bears out the supposition that The Beatles were interested in recording songs that relied much less heavily on repeating common words and much more heavily on using uncommon ones. Compare the 1960-1962 (red) bars to the 1966 (cyan) bars: those two represent the greatest difference of any two years.
1967 (blue): In Hegelian terms, if the early (red) songs are the thesis and the 1966 (cyan) songs are the antithesis, then the blue bars of 1967 represent the synthesis. There are a handful of songs at the higher end of the scale, a return to linguistic simplicity; yet also, and outweighing them, an even stronger focus on the bottom end of the scale, representing linguistic complexity.
1968 and following (purple, black): In the last two years in which The Beatles recorded together (1968-1969), they returned at last to distributions akin to their most productive year, 1963, yet still weighted slightly to the right, the more linguistically complex end of the scale.
This exercise has suggested that songs recorded by The Beatles follow a certain pattern in linguistic complexity driven in part by The Beatles' desire (or their record label's desire) to cater to the perceived tastes of the American market. Following their massive commercial success, they showed more interest in experimental and challenging lyrics. While they finally settled, in their most mature years, into a return to the full span of lyrical complexities, from simple ditties to the challenging, obscure, or specific, the willingness to lean in towards the latter type of songs remained greater in 1967-1969 than in the earlier part of their recording career.