My research focused on increasing computer security by reducing users’ likelihood of installing Trojan Horses: malware hiding inside attractive software. Social cognition research suggests that reading security warnings in software reviews could reduce the likelihood of installing malware. In Study 1, 43 undergraduates viewed user reviews of hypothetical games. Half the reviews were malware warnings. Ratings of the warnings’ strength were used to select strong and weak warnings for Study 2. In Study 2, 45 undergraduates viewed reviews of real computer games. I manipulated the strength and
number of warnings in the reviews. Results showed the likelihood of installing a game was influenced by both the number and strength of malware warnings in reviews: two warnings reduced ratings of installation likelihood more than did one warning; strong warnings reduced the ratings more than did weak ones. Implications and limitations of the findings for social contributions to computer security are discussed.