Some of the world’s most celebrated literary works are filled with gender bias.

Stereotypes were rife among both male and female characters in the descriptors used to identify them, their jobs, and even their roles in the books, according to a study by IBM’s India Research Lab which looked at works shortlisted for the Man Booker Prize between 1969 and 2017. Male characters figured more prominently in plots, and were depicted as powerful, wealthy and strong, it showed, while female characters were more likely to be depicted as beautiful or romantic instead.

The researchers used artificial intelligence to look for instances of such bias in some 275 works shortlisted for the 50-year-old annual literary award given to works of fiction written in English and published in the UK. The study used plot descriptions from book recommendations website Goodreads.

So far, 31 men and 16 women have won the prize.

The analysis “reveals the pervasiveness of gender bias and stereotype in the books on different features like occupation, introductions, and actions associated to the characters in the book,” IBM said.

The researchers used tools like Watson’s Natural Language Understanding API, graph algorithms, and an in-house research prototype for occupation-bias detection for the purpose.

Occupation

Male characters, the study says, have often held “higher-level” jobs. They were more likely to be doctors, professors, novelists, directors, and priests. Female characters were mainly described as “teacher” or a “whore.”

Definition

Across the descriptions of shortlisted books, IBM researchers found stereotypes in the adjectives and verbs associated with male and female characters, too. Men were often depicted to be in a position of power while women were relegated to more submissive roles.

Credit: IBM Research

Male characters were described with terms such as “rich,” “handsome,” and “strong,” while women were identified mainly as “beautiful,” “lovely,” “pretty,” or “romantic.”

The descriptive verbs used to define male and female characters also differed dramatically. Men were often represented as more endearing, brave, and in control, while women were often the ones seeking help, according to IBM. Men were associated with verbs such as “affirms, foresees and encounters,” whereas the verbs used to describe women included “falls, loves, believes and worships, fears.”

Mentions

Male characters, the report found, are also pivotal to the plot, which is why they find far greater mention in the plot descriptions themselves.

Total character mentions showing mentions of male and female characters. Female mentionsare presented in pink and male mentions in blue. Credit: IBM Research India

Male characters in these fictional works get mentioned twice more than their female counterparts. Over time, female characters were mentioned 50% less than males.

However, there has been a slight shift in this trend in recent years as more works of fiction with strong female characters have been published, and books authored by female writers have increasingly been shortlisted for the Man Booker Prize. IBM found that books with stronger female characters were often written by female authors. These include Do Not Say We Have Nothing by Madeleine Thien, How to be Bothby Ali Smith, We Are All Completely Beside Ourselves by Karen Joy Fowler, and The Lowland by Jhumpa Lahiri.

This article first appeared on Quartz.