Research

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My work began with theory and measurement problems in political psychology. My recent work uses generative AI to make the person-level study of belief systems tractable.

Working papers

• Costello, T.H., Pelrine, K., Kowal, M., Arechar, A.A., Godbout, J.-F., Gleave, A., Rand, D., & Pennycook, G. (2026). Large language models can effectively convince people to believe conspiracies. [Preprint]
• Costello, T.H.*, Rabb, N.*, Stagnaro, M.N., Pennycook, G., & Rand, D. (2025). Reducing belief in conspiracy theories as they unfold using large language models. [Preprint] (* shared first authorship)
• Kowal, M., Timm, J., Godbout, J.-F., Costello, T.H., Arechar, A.A., Pennycook, G., … & Pelrine, K. (2025). It’s the thought that counts: Evaluating the attempts of frontier LLMs to persuade on harmful topics.
• Costello, T.H., Pennycook, G., Willer, R., & Rand, D. (2025). Deep canvassing using AI reduces prejudice toward undocumented immigrants. [Preprint]
• Xu, H.G.*, Costello, T.H.*, Schwartz, J.L., Niccolai, L.M., Pennycook, G., & Rand, D. (2025). Personalized dialogues with AI effectively address parents’ concerns about HPV vaccination. [Preprint] (* shared first authorship)
• Czarnek, G., Orchinik, R., Lin, H., Xu, H.G., Costello, T.H., Pennycook, G., & Rand, D.G. (2025). Addressing climate change skepticism and inaction using human–AI dialogues.
• Costello, T.H., Pennycook, G., & Rand, D. (2025). Just the facts: How dialogues with AI reduce conspiracy beliefs. [Preprint]
• Costello, T.H., Waldman, I.W., & Pennycook, G. Mapping the heterogeneity of political beliefs and rigidity. Preprint.
• Costello, T.H., Newton, C., Lin, H., & Pennycook, G. A metacognitive blind spot in intellectual humility measures. Preprint.

Journal articles

• 43. Axt, J.R., Connor, P., Hoogeveen, S., Clark, C.J., Vianello, M., Lahey, J.N., Hahn, A., To, J., Petty, R.E., Costello, T.H., Mitchell, G., Tetlock, P.E., & Uhlmann, E.L. (2026). On the relationship between indirect measures of Black versus White racial attitudes and discriminatory outcomes: An adversarial collaboration using a sample of White Americans. Journal of Personality and Social Psychology. [DOI]
• 42. Pennycook, G., Costello, T.H., & Rand, D.G. (2026). Using artificial intelligence to better understand human intelligence. Current Directions in Psychological Science. [DOI]
• 41. Lin, H., Czarnek, G., Lewis, B., White, J.P., Berinsky, A.J., Costello, T.H., Pennycook, G., & Rand, D.G. (2025). Persuading voters using human–AI dialogues. Nature. [DOI]
• 40. Boissin, E., Costello, T.H., Alonso, D.M., Rand, D., & Pennycook, G. (2025). Dialogues with large language models reduce conspiracy beliefs even when the AI is perceived as human. PNAS Nexus. [DOI]
• 39. Malka, A., Federico, C.M., Costello, T.H., & Panish, A. (2025). Polarized attitudes and anti-democratic orientation: Robust evidence for paradoxical relationships among American partisans. Political Studies. [DOI]
• 38. Lowman, K.L., Costello, T.H., & Patrick, C.J. (2025). Creating scale measures of latent factors: A genetic algorithmic approach. Assessment. [DOI]
• 37. Bowes, S.M., Clark, C.J., Conway, L.G., Costello, T.H., Osborne, D., Tetlock, P.E., & van Prooijen, J.-W. (2025). An adversarial collaboration on the rigidity-of-the-right, symmetry thesis, or rigidity-of-extremes: The answer depends on the question. Political Psychology. [DOI]
• 36. Costello, T.H. (2025). Large language models as disrupters of misinformation. Nature Medicine. [Article]
• 35. Binnendyk, J., Li, S., Costello, T.H., Hale, R., Moore, D.A., & Pennycook, G. (2025). Is overconfidence a trait? An adversarial collaboration. Psychological Science. [DOI]
• 34. Costello, T.H., Pennycook, G., & Rand, D.G. (2025). The problem with AI dialogue at scale — Response. Science, 387, 1158. [DOI]
• 33. Costello, T.H., Pennycook, G., & Rand, D. (2024). Durably reducing conspiracy beliefs through dialogues with AI. Science, 385, eadq1814. [DOI]
• 32. Lilly, K., Costello, T.H., Sibley, C., & Osborne, D. (2024). Identifying “types” of authoritarians: A latent profile analysis of left- and right-wing authoritarianism and social dominance orientation. European Journal of Personality. [DOI]
• 31. Holford, D., Fasce, A., Costello, T.H., & Lewandowsky, S. (2023). Psychological profiles of anti-vaccination argument endorsement. Scientific Reports, 13, 11219. [DOI]
• 30. Bowes, S.M., Costello, T.H., & Tasimi, A. (2023). The conspiratorial mind: A meta-analytic review of motivational and personological correlates. Psychological Bulletin. [DOI]
• 29. Costello, T.H., Zmigrod, L., & Tasimi, A. (2023). Thinking outside the ballot box. Trends in Cognitive Sciences, 27, 605–615. [DOI]
• 28. Malka, A., & Costello, T.H. (2023). Professed democracy support and openness to flagrant authoritarian actions in the American public. American Politics Research, 51, 327–342. [DOI]
• 27. Costello, T.H., Bowes, S.M., Malka, A., Baldwin, M., & Tasimi, A. (2023). Revisiting the rigidity-of-the-right hypothesis: A meta-analytic review. Journal of Personality and Social Psychology, 124, 1025–1052. [DOI]
• 26. Osborne, D., Costello, T.H., Duckitt, J., & Sibley, C. (2023). The causes and societal consequences of authoritarianism. Nature Reviews Psychology, 2, 220–232. [DOI]
• 25. Costello, T.H., & Bowes, S.M. (2023). Absolute certainty and political ideology: A systematic test of curvilinearity. Social Psychological and Personality Science, 14, 93–102. [DOI]
• 24. Costello, T.H., & Patrick, C.J. (2023). Development and initial validation of two brief measures of left-wing authoritarianism: A machine learning approach. Journal of Personality Assessment, 105, 187–202. [DOI]
• 23. Clark, C.J., Costello, T.H., Mitchell, G., & Tetlock, P.E. (2022). The road less travelled: Understanding adversaries is hard but smarter than ignoring them. Journal of Applied Research in Memory and Cognition, 11, 50–53. [DOI]
• 22. Lilienfeld, S.O., Bowes, S.M., Strother, A.N., Liu, C.J., Costello, T.H., Norton, K.A., & Latzman, R.D. (2022). On the association between grants and scholarly achievement among the world’s most eminent psychologists. Current Psychology, 42, 29325–29336. [DOI]
• 21. Costello, T.H., Clark, C.J., & Tetlock, P.E. (2022). Shoring up the shaky psychological foundations of a micro-economic model of ideology: Adversarial collaboration solutions. Psychological Inquiry, 33, 88–94. [DOI]
• 20. Murphy, B.A., Casto, K.V., Watts, A.L., Costello, T.H., Tatum, J.A., Verona, E.V., & Algoe, S.B. (2022). “Feeling powerful” versus “desiring power”: A pervasive and problematic conflation in personality assessment? Journal of Research in Personality, 101, 104305. [DOI]
• 19. Costello, T.H., Bowes, S.M., Stevens, S.T., Waldman, I.W., Tasimi, A., & Lilienfeld, S.O. (2022). Clarifying the structure and nature of left-wing authoritarianism. Journal of Personality and Social Psychology, 122, 135–170. [DOI] [The Atlantic]
• 18. Clark, C.J., Costello, T.H., Mitchell, G., & Tetlock, P.E. (2022). Keep your enemies close: Adversarial collaborations will improve behavioral science. Journal of Applied Research in Memory and Cognition, 11, 1–18. [DOI]
• 17. Bowes, S.M., Costello, T.H., Lee, C., Davis, D.E., McElroy-Heltzel, S., & Lilienfeld, S.O. (2021). Stepping outside the echo chamber: Is intellectual humility associated with less political myside bias? Personality and Social Psychology Bulletin, 48, 150–164. [DOI]
• 16. Costello, T.H., & Lilienfeld, S.O. (2021). Social and economic political ideology consistently operate as mutual suppressors: Implications for personality, social, and political psychology. Social Psychological and Personality Science, 12, 1425–1436. [DOI]
• 15. Avendaño, D., Fasce, A., Costello, T.H., & Adrián-Ventura, J. (2021). Spanish adaptation of the Left-wing Authoritarianism Index. Journal of Personality Assessment, 104, 692–699. [DOI]
• 14. Conway III, L.G., McFarland, J.D., Costello, T.H., & Lilienfeld, S.O. (2021). The curious case of left-wing authoritarianism: When authoritarian persons meet anti-authoritarian norms. Journal of Theoretical Social Psychology, 5, 423–442. [DOI]
• 13. Costello, T.H., Bowes, S.M., & Lilienfeld, S.O. (2020). “Escape from Freedom”: Authoritarianism-related traits, political ideology, personality, and belief in free will/determinism. Journal of Research in Personality, 86, 1–16. [DOI]
• 12. Costello, T.H., Watts, A.L., Murphy, B.A., & Lilienfeld, S.O. (2020). Extending the nomological network of interpersonal sexual objectification to psychopathic and allied traits. Personality Disorders: Theory, Research, and Treatment, 11, 237–248. [DOI]
• 11. Lilienfeld, S.O., Costello, T.H., Bowes, S.M., & Strother, A. (2020). Has psychology found its conscience? European Journal of Personality, 34, 529–530.
• 10. Bowes, S.M., Costello, T.H., Ma, W., & Lilienfeld, S.O. (2020). Looking under the tinfoil hat: Clarifying the personological and psychopathological correlates of conspiracy beliefs. Journal of Personality, 89, 422–436. [DOI]
• 9. Bowes, S.M., Ammirati, R.J., Costello, T.H., Basterfield, C., & Lilienfeld, S.O. (2020). Cognitive biases, heuristics, and logical fallacies in clinical practice: A brief field guide for practicing clinicians and supervisors. Professional Psychology: Research and Practice, 51, 435–445. [DOI]
• 8. Costello, T.H., Smith, S.F., Bowes, S., Riley, S., Berns, G., & Lilienfeld, S.O. (2019). Risky business: Psychopathy, framing effects, and financial outcomes. Journal of Research in Personality, 78, 125–132. [DOI]
• 7. Lilienfeld, S.O., Watts, A.L., Murphy, B., Costello, T.H., Bowes, S.M., Smith, S.F., Latzman, R.D., Haslam, N., & Tabb, K. (2019). Psychopathy as an Emergent Interpersonal Syndrome: Further reflections and future directions. Journal of Personality Disorders, 33, 645–652. [DOI]
• 6. Lilienfeld, S.O., Watts, A.L., Murphy, B., Costello, T.H., Bowes, S.M., Smith, S.F., Latzman, R.D., Haslam, N., & Tabb, K. (2019). Personality disorders as Emergent Interpersonal Syndromes: Psychopathic personality as a case example. Journal of Personality Disorders, 33, 577–622. [DOI]
• 5. Costello, T.H., Unterberger, A., Watts, A.L., & Lilienfeld, S.O. (2018). Psychopathy and pride: Testing Lykken’s hypothesis regarding the implications of fearlessness for prosocial and antisocial behavior. Frontiers in Psychology, 9, 185. [DOI]
• 4. Murphy, B.A., Costello, T.H., Watts, A.L., Berg, J.M., & Lilienfeld, S.O. (2018). Strengths and weaknesses of two empathy measures: A comparison of the measurement precision, construct validity, and incremental validity of two multidimensional indices. Assessment, 27, 246–260. [DOI]
• 3. Bowes, S., Watts, A.L., Costello, T.H., Murphy, B.A., & Lilienfeld, S.O. (2018). Psychopathy and entertainment preferences: Clarifying the role of abnormal and normal personality in music and movie interests. Personality and Individual Differences, 129, 33–37. [DOI]
• 2. Murphy, B.A., Costello, T.H., & Lilienfeld, S.O. (2018). Is empathic contagion helpful or harmful? Overlooked heterogeneity in the Empathy Index. Psychological Assessment, 30, 1703–1708. [DOI]
• 1. Lilienfeld, S.O., & Costello, T.H. (2017). From crisis to salvation. PsycCRITIQUES, 62, 30–34. [DOI]

Chapters & commentaries

Chapters in edited volumes

• Costello, T.H. (2023). The conundrum of measuring authoritarianism. In Cobb, C., Lynn, S.J., & O’Donohue, W. (Eds.), Clinical psychological science: The seminal work of Scott Lilienfeld. Springer: New York, NY. [DOI]
• Lilienfeld, S.O., Basterfield, C., Bowes, S.M., & Costello, T.H. (2020). Nobelists gone wild: Case studies in the domain-specificity of critical thinking. In Sternberg, B., & Halpern, D. (Eds.), Critical thinking in psychology (2nd ed.). Cambridge, United Kingdom: Cambridge University Press. [DOI]

Commentaries & replies

• Costello, T.H., Pennycook, G., & Rand, D.G. (2025). The problem with AI dialogue at scale — Response. Science, 387, 1158. [DOI]
• Costello, T.H., Clark, C.J., & Tetlock, P.E. (2022). Shoring up the shaky psychological foundations of a micro-economic model of ideology: Adversarial collaboration solutions. Psychological Inquiry, 33, 88–94. [DOI]
• Clark, C.J., Costello, T.H., Mitchell, G., & Tetlock, P.E. (2022). The road less travelled: Understanding adversaries is hard but smarter than ignoring them. Journal of Applied Research in Memory and Cognition, 11, 50–53. [DOI]
• Lilienfeld, S.O., Costello, T.H., Bowes, S.M., & Strother, A. (2020). Has psychology found its conscience? European Journal of Personality, 34, 529–530.
• Lilienfeld, S.O., Watts, A.L., Murphy, B., Costello, T.H., Bowes, S.M., Smith, S.F., Latzman, R.D., Haslam, N., & Tabb, K. (2019). Psychopathy as an Emergent Interpersonal Syndrome: Further reflections and future directions. Journal of Personality Disorders, 33, 645–652. [DOI]
• Lilienfeld, S.O., & Costello, T.H. (2017). From crisis to salvation. PsycCRITIQUES, 62, 30–34. [DOI]

Popular press

• Costello, T.H., Pennycook, G., & Rand, D. (2025, October 30). Chatbots are surprisingly effective at debunking conspiracy theories. MIT Technology Review. [Article]
• Costello, T.H. (2023). Curated summary: “Current research overstates American support for political violence” by Westwood, Grimmer, Tyler, and Nall (2022). Library of Partisan Animosity.
• Costello, T.H., & Bowes, S.M. (2022, August). Popper was right about the link between certainty and extremism. Psyche. [Article]
• Lilienfeld, S.O., Bowes, S.M., Costello, T.H., & Strother, A. (2020, March/April). Intellectual humility: A guiding principle for the skeptical movement. Skeptical Inquirer.
• Basterfield, C., Lilienfeld, S.O., Bowes, S., & Costello, T.H. (2020, May/June). The Nobel disease: When intelligence fails to protect against irrationality. Skeptical Inquirer.

Curriculum vitae (PDF).