The internet and social media are the main source of everyday information for university students, despite the high presence of fake news. Therefore, it is necessary to develop critical thinking and learn to counter-argue in order to filter the information received through these media.

This creates the need to design interventions that help students critically confront fake news. Since the use of video games for educational purposes can offer a high level of motivation and promote the development of digital literacy and skills among students, this study proposes an intervention focused on a session with a video game (serious game). Serious games can be defined as games whose primary intention is training or learning with definable educational objectives, rather for entertainment.

The main objective of this study is to implement and test an educational intervention based on a serious game and focused on the identification of misinformation using four indicators (Authorship, Data quality, Emotional language, and Interest) to justify the credibility of a fake new.

Methodology: The study involved 212 first-year undergraduate students (79,4% women) from Education, Psychology, and Nursing degree programs at Spanish public universities in Cantabria, Catalonia and Madrid. The research design follows a pre-post study in which the quantity and type of criteria used by students to justify the degree of credibility of four fake news articles are compared. The level of credibility was measured using a Likert scale from 0 to 10. The justifications provided by the students were categorized through consensus by two expert researchers.

The intervention task consisted of a 50-minute session with the following components:
a) Initial stance on the topic of news;
b) Pre-test: assessment of the credibility of a fake new article and reasoned justification;
c) Educational intervention: during 30 minutes, students played the serious game on their mobile phones. The game was designed to address misinformation and fake news through questions related to the four indicators, allowing progression through levels based on the ability to detect different elements of misinformation;
d) Post-test: assessment of the credibility of a new fake news article and reasoned justification of the credibility level.

Preliminary results, with a subsample (n=50), indicate statistically significant differences before and after the use of the video game in the total number of indicators used by students to justify the credibility degree assigned to a news article (one-tailed p=.037). More specifically, we observed an increase in the percentage of students incorporating the Authorship criterion (one-tailed p=.026). We conclude that the most frequently used indicator by university students in both the pre-test and post-test was Data quality, although at a low frequency, as most students tend to justify credibility based on the content of the news and their prior knowledge.

These results highlight the difficulties university students face in evaluating fake news based on reliability indicators and underscore the need for educational interventions focused on developing criteria to detect and counterargue misinformation.

Keywords: Critical thinking, Serious game, Misinformation, Argumentation, Higher education, Fake news.