What was the study conducted where researchers scanned thousands of books across decades to research emotion?

[Kevin7]

[Mrs. Ted H]

The Expression of Emotions in 20th Century Books Published: March 20, 2013
Alberto Acerbi, Vasileios Lampos, Philip Garnett, R. Alexander Bentley

We report here trends in the usage of “mood” words, that is, words carrying emotional content, in 20th century English language books, using the data set provided by Google that includes word frequencies in roughly 4% of all books published up to the year 2008. We find evidence for distinct historical periods of positive and negative moods, underlain by a general decrease in the use of emotion-related words through time. Finally, we show that, in books, American English has become decidedly more “emotional” than British English in the last half-century, as a part of a more general increase of the stylistic divergence between the two variants of English language.

We analyze trends in the past century of mood words in books, using Google's Ngram database. Google's Ngram database represents a 4% digitally–scanned sample of several centuries of books, for a total of 5,195,769 volumes. The corpus contains texts in different languages, and, for English, a further distinctions is made between American English and British English (according to the country of publication, i.e. United States versus Great Britain). Additionally, a subset of English texts collects only fiction books. Titles of books present in the corpus are not available because of copyright reasons . The corpus gives information on how many times, in a given year, an 1-gram or an n-gram is used, where an 1-gram is a string of characters uninterrupted by space (i.e. a word, but also numbers, typos, etc.) and an n-gram is a sequence of n 1-grams.

We make use of six unique lists of terms to characterize mood categories labeled as Anger, Disgust, Fear, Joy, Sadness, and Surprise. These mood word lists have previously been applied on a study of U.K. Twitter content, which showed that changes in these mood word frequencies identified real-world events such as the unexpected deaths of popular personas, public unrest, or natural disasters. We extend the time scale of this analysis by tracking mood word frequencies through the past century of Google book data. We find a general decrease in the use of mood terms through time, which underlies a distinct increase in emotional word usage in American books versus British books in the last half century.

Our analysis yielded three main results. First, we can distinguish between ‘happy’ and ‘sad’ periods in the data...shows that moods tracked broad historical trends, including a ‘sad’ peak corresponding to Second World War, and two ‘happy’ peaks, one in the 1920's and the other in the 1960's. In more recent years we can see a ‘sad’ period starting from the 1970's, with an increase in ‘happiness’ in the last years of the data set. Interestingly, the First World War does not seem to register a particular change in mood words.

Our second finding is a clear decrease in the overall use of mood words through time...Notably, the mood of Fear, which declined throughout most of the early century, has increased markedly since the 1970's, in contrast to the continued decline of other moods

Our third finding is that, since about 1960, American books have increased their mood contents compared to British books. This divergence between American and British English occurs within the context of the overall decline in the use of mood words... Somewhat surprisingly, this difference has apparently developed only since the 1960s, and as part of a more general stylistic differentiation in American versus British English, reflected similarly in content-free word frequencies. This relative increase of American mood word use roughly coincides with the increase of anti–social and narcissistic sentiments in U.S. popular song lyrics from 1980 to 2007.
http://www.plosone.org/article/info%3Ado...ne.0059030