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 determinants of trust, cooperation and aggression. Although the papers to prove it are still in prep or under review, my current research primarily concerns human-AI interaction during crises.


Holbrook, C., Holman, D., Clingo, J. & Wagner, A. R. (2023, October 9). Overtrust in AI recommendations to kill. 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. (in press). Investigating human-robot overtrust during crises. Hybrid Human Artificial Intelligence Conference MULTITTRUST Workshop. PREPRINT

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.)

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

Ocampo, D., Sullivan, J., Dayer, A., Palka, E., Betschart, N., & Holbrook, C. (2022). Prosocial aggression tracks genetic relatedness distinctly from emotional closeness. Emotion. 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. 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

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

Lopez, L.D., Moorman, K., Schneider, S., Baker, M.N., & Holbrook, C. (2019). Morality is relative: Anger, disgust and aggression as contingent responses to sibling versus stranger harm. Emotion. PDF

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.,* Pollack, J.,* Zerbe, J.G., & Hahn-Holbrook, J. (2018). Perceived supernatural support enhances battle confidence: A knife combat field study. Religion, Brain & Behavior. PDF
(* equal authorship.)

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. 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. a href= "http://colinholbrook.com/Hahn_Holbrook_Holbrook_Social_Neuroedocrinology.pdf" target="_blank">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. PDF
* Note that this reply also contains extensive additional analyses.

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