Adjectives and adverbs in life sciences across 50 years: implications for emotions and readability in academic texts

Writing in a clear and simple language is critical for scientific communications. Previous studies argued that the use of adjectives and adverbs cluttered writing and made scientific text less readable. The present study aims to investigate if the articles in life sciences have become more cluttered and less readable across the past 50 years in terms of the use of adjectives and adverbs. The data that were used in the study were a large dataset of 775,456 scientific texts published between 1969 and 2019 in 123 scientific journals. Results showed that an increasing number of adjectives and adverbs were used and the readability of scientific texts have decreased in the examined years. More importantly, the use of emotion adjectives and adverbs also demonstrated an upward trend while that of nonemotion adjectives and adverbs did not increase. To our knowledge, this is probably the first large scale diachronic study on the use of adjectives and adverbs in scientific writing. Possible explanations to these findings were discussed.