How Facebook's newsfeed algorithm shapes childhood vaccine hesitancy: An algorithmic fairness, accountability, and transparency (FAT) perspective

Vaccine hesitancy is the delay or refusal of vaccination when vaccines are available. Over the last decade, many reports have suggested that the proliferation of vaccine disinformation and misinformation on social media has aggravated the vaccine-hesitancy problem. Access to vaccine dis(mis)information on social media is deemed partly responsible for the resurfacing of vaccine-preventable diseases (e.g., measles). Although studies have examined social media dis(mis)information, including that related to vaccines, the newsfeed algorithm, which determines the content social media users see, has received scant attention in the literature. We examine how people's perceptions of the fairness, accountability, and transparency (FAT) of the Facebook newsfeed algorithm influence their intention to vaccinate their children. We find that people's perceptions of the Facebook newsfeed algorithm's FAT increase their negative attitudes toward vaccination (fairness and transparency). However, they decrease users' perceptions of antivaccination norms on Facebook (fairness, accountability, and transparency). Negative attitudes toward vaccination decrease the intention to vaccinate, as do perceptions of Facebook antivaccination norms. Our findings demonstrate that to decrease the effectiveness of vaccine dis(mis)information, it is critical to educate the public about how social media newsfeed algorithms make content-display decisions.