[, , , ] In a widely discussed paper, Michel and colleagues [-@michel_quantitative_2011] analyzed the content of more than 5 million digitized books in an attempt to identify long-term cultural trends. The data that they used has now been released as the Google NGrams dataset, and so we can use the data to replicate and extend some of their work.
In one of the many results in the paper, Michel and colleagues argue that we are forgetting faster and faster. For a particular year, say "1883", they calculated the proportion of 1-grams published in each year between 1875 and 1975 that were "1883". The reasoned that this proportion is a measure of the interest in events that happened in that year. In Fig 3a they plot the usage trajectories for three years: 1883, 1910, and 1950. These three years share a common pattern: little use before that year, then a spike, then decay. Next, t