Home Publications Vita Contact Links Colin Holbrook Associate Professor of Cognitive and Information Sciences University of California, Merced I study decision-making under contexts of threat, with particular focus on the social and emotional determinants of trust, cooperation and aggression. Although most of the papers to prove it are still in prep or under review, my current research primarily concerns human-AI interaction during crises. PUBLICATIONS Holbrook, C., Holman, D., Clingo, J. & Wagner, A. R. (2024). Overtrust in AI recommendations about whether or not to kill: Evidence from two human-robot interaction studies. Scientific Reports, 14, 19751. LINK Samore, T., Fessler, D. M. T., Sparks, A. M., Holbrook, C. ... Wang, X. (2024). Accordance and conflict between religious and scientific precautions against COVID-19 in 27 societies. Religion, Brain & Behavior, 1–20. https://doi.org/10.1080/2153599X.2024.2363757 PDF Dayer, A., Aswamenakul, C., Turner, M. A., Nicolay, S., Shurik, K., & Holbrook, C. (2024). Intuitive moral bias favors the religiously faithful: Evidence from two societies. Scientific Reports, 14, 18291. LINK Lobato, E. & Holbrook, C. (2024). Prejudice is epistemically unwarranted belief. Applied Cognitive Psychology, 38(3), e4216. https://doi.org/10.1002/acp.4216 LINK Holbrook, C., Krishnamurthy, U., Maglio, P., & Wagner, A. R. (2024, June 22). Physical anthropomorphism (but not gender presentation) influences trust in household robots. PsyArXiv. PREPRINT Yin, Y., Nayyar, M., Holman, D., Lucas, G., Holbrook, C., & Wagner, A. (2024, June 24). Validation and evacuee modeling of virtual robot-guided emergency evacuation experiments. PsyArXiv. PREPRINT Moser, C., Holbrook, C., Ellks, R., & Jones, A. (2024, June 24). Possessing potential weapons (still) heightens anger perception: Replicating and extending a test of Error Management Theory. PsyArXiv. PREPRINT Holbrook, C., Holman, D., Wagner, A. R., Marghetis, T., Lucas, G., Sheeran, B., Surendran, V., Armagost, J., Spazak, S., Andor, K., & Yin, Y. (2023). Investigating human-robot overtrust during crises. In P. K. Murukannaiah, T. Hirzle (Eds.) Proceedings of the Workshops at the Second International Conference on Hybrid Human-Artificial Intelligence (164-168) (CEUR-WS.org). PDF Holbrook, C., Fessler, D. M. T., Sparks, A. M., Johnson, D. L., Samore, T., & Reed, L. I. (2023). Coalitionality shapes moral elevation: Evidence from the U.S. Black Lives Matter protest and counter-protest movements. Royal Society Open Science, 10, 220990. LINK Samore, T., Fessler, D. M. T., Sparks, A. M., Holbrook, C., Aaroe, L., Baeza, C. G., … Wang, X. (2023). Greater traditionalism predicts COVID-19 precautionary behaviors across 27 societies. Scientific Reports. LINK Sheeran, B. P., Wagner, A. R., Holbrook, C., & Holman, D. (2023, January 23-27). Robot guided emergency evacuation from a simulated space station [Paper presentation]. AIAA SciTech 2023 Forum, National Harbor, MD. doi.org/10.2514/6.2023-0156 PDF *Fessler, D. M. T., *Merrill, W., Holbrook, C., & Ackerman, J. (2023). Beware the foe who feels no pain: Associations between relative formidability and pain sensitivity in three U.S. online studies. Evolution & Human Behavior, 44(1), 1-10.  LINK (* equal authorship.) Ocampo, D., Sullivan, J., Dayer, A., Palka, E., Betschart, N., & Holbrook, C. (2023). Prosocial aggression tracks genetic relatedness distinctly from emotional closeness. Emotion, 23(6), 1575-1583. PDF Holbrook, C., Yoon, L., Fessler, D.M.T., Moser, C., Jimenez Delgado, S., & Kim, H. (2022). Moral parochialism and causal appraisal of transgressive harm in Seoul and Los Angeles. Scientific Reports, 12, 14227. LINK Wagner, A. R., Holbrook, C., Holman, D., Sheeran, B., Surendran, V., Armagost, J., Spazak, S., & Yin, Y. (2022, November 17-19). Using virtual reality to simulate human-robot emergency evacuation scenarios [Paper presentation]. AAAI AI-HRI Fall Symposium Series 2022, Arlington, VA. arXiv:2210.08414 PDF Holbrook, C. & Hahn-Holbrook, J. (2022). Evolved to learn: Emotions as calibrational adaptations. In D. Dukes, E. Walle, A. Samson (Eds.), The Oxford Handbook of Emotional Development. Oxford: Oxford University Press. PDF Holbrook, C., Iacoboni, M., Gordon, C., Proksch, S., Makhfi, H., & Balasubramaniam, R. (2021). Posterior medial frontal cortex regulates sympathy: A TMS study. Social Neuroscience, 16(6), 595-606. PDF Kupfer, T.R., Fessler, D.M.T., Lal, V., Wu, B., Hwang, T., Alas, S., Samore, T., Sparks, A.M., Sakhamuru, T., & Holbrook, C. (2021). The skin crawls, the stomach turns: Ectoparasites and pathogens elicit distinct defensive responses in humans. Proceedings of the Royal Society B: Biological Sciences, 288: 20210376. PDF Samore, T., Fessler, D. M., Sparks, A. M., & Holbrook, C. (2021). Of pathogens and party lines: Social conservatism positively associates with COVID-19 precautions among Democrats but not Republicans. PLoS ONE 16(6): e0253326. LINK Lopez, L.D., Moorman, K., Schneider, S., Baker, M.N., & Holbrook, C. (2021). Morality is relative: Anger, disgust and aggression as contingent responses to sibling versus stranger harm. Emotion, 21(2), 376-390. PDF Holbrook, C., Iacoboni, M., Gordon, C., Proksch, S., & Balasubramaniam, R. (2020). Posterior medial frontal cortex and threat-enhanced religious belief: A replication and extension. Social Cognitive and Affective Neuroscience. PDF Lobato, E.J.C., Powell, M., Padilla, L., & Holbrook, C. (2020). Factors predicting willingness to share COVID-19 misinformation. Frontiers in Psychology. PDF Scrivner, C., Holbrook. C., Fessler, D.M.T., & Maestripieri, D. (2020). Gruesomeness conveys formidability: Perpetrators of gratuitously grisly acts are conceptualized as larger, stronger, and more likely to win. Aggressive Behavior, 46(5), 400-411. PDF Holbrook, C. & Hahn-Holbrook, J. (2020). Conservative extremism and threat appraisal [Commentary]. In A. Lopez, H. Sheikh (Eds.), Extremism in Historical and Evolutionary Perspective. The Evolution Institute. PDF Holbrook, C.,* Pollack, J.,* Zerbe, J.G., & Hahn-Holbrook, J. (2020). Perceived supernatural support enhances battle confidence: A knife combat field study. Religion, Brain & Behavior, 10(1), 6–17. PDF (* equal authorship.) Sparks, A.M., Fessler, D.M.T., & Holbrook. C. (2019). Elevation, an emotion for prosocial contagion, is experienced more strongly by those with greater expectations of the cooperativeness of others. PLOS-ONE. LINK Lobato, E., Tabatabaeian, S., Fleming, M., Sulzmann, S. & Holbrook, C. (2019). Religiosity predicts evidentiary standards. Social Psychological and Personality Science. PDF Tabatabaeian, S., Holbrook, C. & Jennings, C.D. (2019). A re-examination of the interrelationships between attention, eye behavior, and creative thought. In A.K. Goel, C.M. Seifert, & C. Freksa (Eds.) Proceedings of the 41st Annual Conference of the Cognitive Science Society (p. 3590). Montreal, QB: Cognitive Science Society. Fessler, D.M.T., Sparks, A.M., Samore, T., & Holbrook, C. (2019). Does observing reciprocity or exploitation affect elevation, a mechanism driving prosociality? Evolutionary Human Sciences, 1, E3. doi:10.1017/ehs.2019.3 PDF Samore, T., Fessler, D.M.T., Holbrook, C., & Sparks, A.M. (2018). Electoral fortunes reverse, mindsets do not: Political orientation, credulity, and conspiracism following the 2016 U.S. elections. Public Library of Science ONE. PDF Holbrook, C. (2018). Cues of violent intergroup conflict diminish perceptions of robotic personhood. ACM Transactions on Interactive Intelligent Systems, 8(4), Article 28. PDF Holbrook, C., Gordon, C.G., & Iacoboni, M. (2018). Continuous theta burst stimulation of posterior medial frontal cortex to experimentally reduce ideological threat responses. Journal of Visualized Experiments. VIDEO & PDF Pollack, J.,* Holbrook, C.,* Fessler, D.M.T., Sparks, A. M., & Zerbe, J.G. (2018). May God guide our guns: Visualized supernatural aid heightens team confidence in a paintball battle simulation. Human Nature,29(3), 311-327. PDF (* equal authorship.) Holbrook, C., Lopez-Rodriguez, L., Gomez, Á. (2018). Battle of wits: Militaristic conservatism and warfare cues enhance the perceived intellect of allies versus adversaries. Social Psychological and Personality Science, 8, 670-678. PDF Hahn-Holbrook, J., & Holbrook, C. (2018). The social neuroendocrinology of pregnancy and breastfeeding in mothers (and others). In P. Mehta and O. Schultheiss, (Eds.), International Handbook of Social Neuroendocrinology. New York: Routledge Press. PDF Sparks, A., Fessler, D.M.T., Chan, K.Q., Ashokkumar, A., & Holbrook, C. (2018). Disgust as a mechanism for decision making under risk: Illuminating sex differences and individual risk-taking correlates of disgust propensity. Emotion, 18(7), 942-958. PDF Fessler, D.M.T., Pisor, A.C., & Holbrook, C. (2017). Political orientation predicts credulity regarding putative hazards. Psychological Science, 28(5), 651-660. PDF Holbrook, C., Lopez-Rodriguez, L., Fessler, D.M.T., Vazquez, A., Gomez. A. (2017). Gullivers politics: Conservatives envision potential enemies as readily vanquished and physically small. Social Psychological and Personality Science, 8, 670-678. PDF Fessler, D.M.T. & Holbrook, C. (2016). Synchronized behavior increases assessments of the formidability and cohesion of coalitions. Evolution and Human Behavior, 6, 502-509. PDF Holbrook, C., Izuma, K., Deblieck, C., Fessler, D.M.T., & Iacoboni, M. (2016). Neuromodulation of group prejudice and religious belief. Social Cognitive & Affective Neuroscience, 11, 387-394. PDF Holbrook, C. (2016). Branches of a twisting tree: Domain-specific threat psychologies derive from shared mechanisms. Current Opinion in Psychology, 7, 81-86. PDF Holbrook, C., Fessler, D.M.T., & Navarrete, C. (2016). Looming large in others eyes: Racial stereotypes illuminate dual adaptations for representing threat versus prestige as physical size. Evolution and Human Behavior, 37, 67-78. PDF Fessler, D.M.T., Holbrook, C., Kanovsky, M., Barrett, H.C., Bolyanatz, A.H., Gervais, M., Gurven, M., Henrich, J., Kushnick, G., Pisor, A.C., Stich, S., von Reuden, C., & Laurence, S. (2016). Moral parochialism misunderstood: A reply to Piazza and Sousa. Proceedings of the Royal Society B: Biological Sciences, 283, 20152628 PDF * Note that this reply also contains extensive additional analyses. 283(1823):20152628. Holbrook, C., Fessler, D.M.T., & Pollack, J. (2016). With God on your side: Religious primes reduce the envisioned physical formidability of a menacing adversary. Cognition, 146, 387-392. PDF Fessler, D.M.T., Holbrook, C., & Dashoff, D. (2016). Dressed to kill? Visible markers of coalitional affiliation enhance conceptualized formidability. Aggressive Behavior, 42, 299-309. PDF Sousa, P., Holbrook, C., & Swiney, L. (2015). Moral asymmetries in judgments of agency withstand ludicrous causal deviance. Frontiers in Psychology. PDF Fessler, D.M.T., Barrett, H.C., Kanovsky, M., Stich, S., Holbrook, C., Henrich, J., Bolyanatz, A.H., Gervais, M., Gurven, M., Kushnick, G., Pisor, A.C., von Reuden, C., & Laurence, S. (2015). Moral parochialism and contextual contingency across seven disparate societies. Proceedings of the Royal Society B: Biological Sciences, 282, 20150907. PDF Holbrook, C., & Fessler, D.M.T. (2015). The same, only different: Threat management systems as homologues in the tree of life. In Handbook of Personal Security, P. J. Carroll, R. M. Arkin, and A. L. Wichman, eds., pp. 95-109. New York: Psychology Press. PDF Fessler, D.M.T., Holbrook, C., & Fleischman, D.S. (2015). Assets at risk: Menstrual cycle variation in the envisioned formidability of a potential sexual assailant reveals a component of threat assessment. Adaptive Human Behavior & Physiology, 1, 270-290. PDF Holbrook, C., Hahn-Holbrook, J., & Holt-Lunstad, J. (2015). Self-reported spirituality correlates with endogenous oxytocin. Psychology of Religion and Spirituality, 7, 46-50. PDF Fessler, D.M.T., & Holbrook, C. (2014). Marching into battle: Synchronized walking diminishes the conceptualized formidability of an antagonist in men. Biology Letters. PDF Fessler, D.M.T., Holbrook, C., Tiohkin, L., & Snyder, J.K. (2014). Sizing up Helen: Nonviolent physical risk-taking enhances the envisioned bodily formidability of women. Journal of Evolutionary Psychology, 12, 67-80. PDF Holbrook, C., Galperin, A., Fessler, D.M.T., Johnson, K., Bryant, G., & Haselton, M. (2014). If looks could kill: Anger judgments are intensified by affordances for doing harm. Emotion, 14, 455-461. PDF Fessler, D.M.T., Holbrook, C., & Gervais, M. (2014). Men's physical strength moderates conceptualizations of prospective foes in two disparate human societies. Human Nature, 25, 393-409. PDF Fessler, D.M.T., Tiokhin, L., Holbrook, C., Gervais, M., & Snyder, J.K. (2014). Foundations of the "Crazy Bastard" Hypothesis: Nonviolent physical risk-taking enhances conceptualized formidability. Evolution and Human Behavior, 35, 26-33. PDF Holbrook, C., Piazza, J., & Fessler, D.M.T. (2014). Further challenges to the "Authentic" / "Hubristic" model of pride: Conceptual clarifications and new evidence. Emotion, 14, 38-42. PDF * Note that this reply reports an additional study. Holbrook, C., Piazza, J., & Fessler, D.M.T. (2014). Conceptual and empirical challenges to the 'Authentic' versus 'Hubristic' model of pride. Emotion, 14, 17-32. PDF Fessler, D.M.T., Holbrook, C., Pollack, J., & Hahn-Holbrook, J. (2014). Stranger danger: Parenthood and child presence increase the envisioned bodily formidability of menacing men. Evolution and Human Behavior, 35, 109-117. PDF Jonas, E., McGregor, I., Klackl, J., Agroskin, D., Fritsche, I., Holbrook, C., Nash, K., Proulx, T., & Quirin, M. (2014). Threat and defense: From anxiety to approach. In J. M. Olson & M. P. Zanna (Eds.), Advances in Experimental Social Psychology (pp. 219 - 286). San Diego, CA: Academic Press. PDF Fessler, D.M.T., & Holbrook, C. (2013). Bound to lose: Physical incapacitation increases the conceptualized size of an antagonist in men. PLOS-ONE. PDF Piazza, J., Sousa, P., & Holbrook, C. (2013). Authority dependence and judgments of utilitarian harm. Cognition, 128, 261-270. PDF Holbrook, C., & Sousa, P. (2013). Supernatural beliefs, unconscious threat, and judgment bias in Tibetan Buddhists. Journal of Cognition and Culture, 13, 33-56. PDF Fessler, D.M.T., & Holbrook, C. (2013). Friends shrink foes: The presence of comrades decreases the envisioned physical formidability of an opponent. Psychological Science, 24, 797-802. PDF Holbrook, C., & Fessler, D.M.T. (2013). Sizing up the threat: The envisioned physical formidability of terrorists tracks their leaders' failures and successes. Cognition, 127, 46-56. PDF Holbrook, C., Fessler, D.M.T., & Gervais, M. (2013). Revenge without redundancy: Functional outcomes do not require discrete adaptations for vengeance or forgiveness [Commentary]. Behavioral and Brain Sciences, 36, 22-23. PDF Fessler, D.M.T., & Holbrook, C. (2013). Baumard et al.'s moral markets lack market dynamics [Commentary]. Behavioral and Brain Sciences, 36, 89-90. PDF Fessler, D.M.T., Holbrook, C., & Snyder, J.K. (2012). Weapons make the man (larger): Relative formidability influences perceived size and strength. PLOS-ONE. PDF Holbrook, C., Sousa, P., & Hahn-Holbrook, J. (2011). Unconscious vigilance: Worldview defense without adaptations for terror, coalition or uncertainty management. Journal of Personality and Social Psychology, 101, 451-466. PDF Hahn-Holbrook, J., Holt-Lunstad, J., Holbrook, C., Coyne, S., & Lawson, E. T. (2011). Maternal defense: Breastfeeding increases aggression by decreasing stress. Psychological Science, 22, 1288-1295. PDF Hahn-Holbrook, J.*, Holbrook, C.*, & Haselton, M. (2011). Parental precaution: Adaptive ends and neurobiological means. Neuroscience and Biobehavioral Reviews, 35, 1052-1066. (*equal authorship.) PDF Sousa, P., & Holbrook, C. (2010). Folk concepts of intentional action in the contexts of amoral and immoral luck. Review of Philosophy and Psychology, 1, 351-370. PDF Hahn-Holbrook, J., Holbrook, C., & Bering, J. (2010). Snakes, spiders, strangers: How the evolved fear of strangers may misdirect efforts to protect children from harm. In J. M. Lampinen & K. Sexton-Radek (Eds.) Protecting children from violence: Evidence-based interventions. New York: Psychology Press. PDF Sousa, P., Holbrook, C., & Piazza, J. (2009). The morality of harm. Cognition, 113, 80-92. PDF