Personalization of social media content improves targeting. Social media platforms provide information tailored to each user’s preferences. Users personalize their social media experience across platforms by selecting who or what they follow. Machine learning takes that personalization further, serving up content based on individuals’ previous choices and social media metadata, which helps content producers more accurately tailor and target content. It’s necessary for revenue from both advertising and data mining, which have made huge investments to set up and make social media platforms commercially viable.52 However, personalization technologies also allow malicious information to spread via social media to influence people efficiently, which can lead to attitudinal and behavior changes conducive to conflict. This happens via various individual cognitive processes that are susceptible to exploitation. For example:    The primacy effect: Users at a formative state with respect to an issue, such as young people and violent extremism, may form conclusive opinions on the basis of the information that is first acquired, regardless of its veracity.53 The illusory truth effect: Because of personalization, users that demonstrate an interest in violent extremism are more likely to see additional content that promotes radicalization. When people are exposed and re-exposed to information, they tend to believe that it is more truthful because they cannot remember the original source.54 The availability heuristic and confirmation bias: On social media, individuals’ preferences and algorithmic targeting will expose them to content that further confirms rather than discounts their views.55 Increasing polarization exacerbates conflict risk (especially in vulnerable societies). Though the internet can theoretically “democratize information” by connecting people across geographic and identity divisions, the personalization of social media platforms (and even search algorithms) instead functions to parse users’ information access into relatively uniform groups that share preferences and demographic characteristics. When there is dissonance between people online, cutting ties via unfriending or unfollowing others is relatively easy compared with real-world social networks, encouraging further segregation. The resulting “social media bubbles” or “echo chambers” have implications for conflict, particularly in settings with volatile root causes. In these contexts, discourse, attitudes, norms and “facts” begin sorting along ethnic, ideological, linguistic or other societal cleavages. Individuated social media news streams provide user groups with content and social proof that justifies their attitudes, beliefs and prejudices, fueling disagreement and eroding the shared language and knowledge through which people could otherwise find common ground.56 Identity protective cognition provides one explanation for why groups polarize, and describes a form of reasoning in which people selectively credit and dismiss factual information to protect their status within an affinity group.57 Social media fills the trust gap and intensifies rumor dynamics. The conflict-driving effect of personalized information is exacerbated by the low levels of trust that are prevalent in settings with histories 52 Mark Hachman, “The Price of Free: How Apple, Facebook, Microsoft and Google Sell You to Advertisers,” PCWorld, October 1, 2015, https://www.pcworld.com/article/2986988/privacy/the-price-of-free-how-apple-facebook-microsoft-and-google-sell-you-to-advertisers.html. 53 Vasu Et Al. (2018) Fake News: National Security In The Post-truth Era. S. Rajaratnam School Of International Studies: Policy Report. 54 Ibid. 55 Heshmat, S. (2015) What is confirmation bias? Psychology Today. Available: https://www.psychologytoday.com/us/blog/science-choice/201504/whatis-confirmation-bias 56 Allcott, H. and Gentzkow, M. (201) “Social Media and Fake News in the 2016 Election.” Journal of Economic Perspectives 31, no. 2: 230. 57 NATO (2017) Digital Hydra:Security Implications Of False Information Online. Available: https://www.stratcomcoe.org/digital-hydra-securityimplications-false-information-online MERCY CORPS The Weaponization of Social Media: How social media can spark violence and what can be done about it 18