Political violence stems from both the extreme left and right, but not in equal measure. More ideologically motivated killings have been perpetrated by the far-right in the United States than by far-left movements over the last four decades,1 and attacks by members of the far-right have increased precipitously in the last few years.2 A similarly asymmetric and accelerating association between violence and the political right has been observed in countries throughout the world.3 A Darwinian approach to the threat psychologies distinguishing left from right political orientation can help make sense of the link between violence and extreme conservatism.

Broadly speaking, when environments are dangerous, vigilance against threats and adherence to tried-and-true behaviors are adaptive strategies. Conversely, when environments are safe, threat-vigilance and adherence to the tried-and-true can lead to wasteful expenditures of effort on defense, and failures to adopt beneficial innovations. Given that environmental danger varies, and that individuals vary in the degree to which they are equipped to confront or endure threats, natural selection favors genetic variation within populations in reactivity to indications of threat. This distribution in relative threat-reactivity appears to manifest in some of the values and intuitions informing one’s political orientation, and may partially explain the abiding distinction between conservatives, who prioritize the preservation of cultural traditions and the welfare of the in-group as safeguards against a world perceived as fraught with enemies, and progressives, who view change and between-group cooperation as beneficial opportunities in a world perceived as relatively safe.4 Consistent with this functional perspective, convergent evidence indicates that conservatives process threat-related cues with greater salience and reactivity than do progressives.5  Notwithstanding recent evidence that political orientation does not reliably track skin conductance responses to threatening pictures,6 conservatives have been found more distracted by threatening imagery,7-9 more emotionally reactive to threatening images,6 and more likely to perceive ambiguous facial expressions as indicating malevolent intent relative to progressives.10

Such varied expressions of threat-reactivity may be understood as heightened negativity bias, a pattern observed across many species.11,12 Insofar as threats are more imminent than benefits of comparable magnitude, and can preclude the opportunity to reap benefits (e.g., due to injury or death), failing to detect and respond to potential threats carries greater fitness costs than failing to detect and respond to potential benefits. Natural selection, therefore, favors the evolution of psychological mechanisms that assign greater weight to potential threats than to potential benefits or other sorts of information. In our species, information regarding potential threats has been found more attention-grabbing, memorable, and evocative than information about potential benefits,13 and people tend to believe false claims to a greater degree when framed as threats than as benefits.14

The tendency to believe spurious claims about threats makes adaptive sense. As in other forms of negativity bias, failing to believe true threat claims is often costlier than mistakenly believing false threat claims, due to the lopsided difference between the costs of suffering harm versus unnecessary precaution.14 Conservatives appear more prone to negativity bias with regard to credulity toward false threat claims, even when the threats in question are apolitical in nature, with no such difference observed regarding claims about potential benefits.15,4 The overall findings indicate that the link between political orientation and threat-credulity is not explicable by demographic variables, differences in reasoning abilities, or gullibility regarding non-threat topics.15 Rather, conservatives appear to believe false claims about threats due to an underlying threat-reactivity which manifests in an array of perceptual, affective, cognitive, and behavioral tendencies which were likely advantageous in perilous ancestral environments.

Political orientation seems to be heritable as well as contingent on environmental influences. A cross-cultural analysis of over 12,000 adult twin pairs found evidence that genetic factors contribute 10-59% of the variance in political ideology in samples spanning four decades and five societies.16 In addition, early exposure to unsafe environments increases threat-reactivity throughout the lifespan,17,18 potentially inclining individuals toward conservatism. Within-group exchanges of information (i.e., “information bubbles”) may solidify such endogenous propensities and strengthen investment in one’s left or right political coalition.

If, as the large and growing body of evidence outlined above suggests, conservatives truly are more threat-reactive and more credulous of alleged threats, then a polarized media environment in which conservatives are inundated with disinformation about outgroup threats may set the stage for far-right extremism to flourish. Indeed, levels of conservatism track the intensity of belief in conspiracy theories.4 The functional model of conservatism sketched here predicts that information regarding ostensibly threatening out-groups should garner greater attention, emotional salience, memory, and credulity among conservative audiences, potentially engendering a positive feedback loop wherein individuals feel motivated to seek further information regarding putative threats—and to confront them aggressively.

Crucially, the pattern of heightened reactivity and credulity toward potential threats characteristic of the conservative mind is not associated with fearfulness or timidity, but with confidence in the ability to triumph through force. Cues of threat often exacerbate intergroup antipathy,19,20 and conservatives display not only a lower threshold for identifying out-group members as threats,10,21 but also greater confidence in achieving victory through warfare,21 in a pattern observed in the United States, the United Kingdom, and Spain, and which should theoretically replicate in other societies.22,23 By contrast, the same data portray progressives as less inclined to categorize out-group members as threats, less confident in attaining victory through force, and more inclined to seek negotiation and accommodation. As such, far-right extremists commit acts of political violence moreso than their far-left counterparts in an exaggerated pattern consonant with the differences observed among individuals who fall within the normal spectrum of political attitudes.

To be clear, the overwhelming majority of conservatives do not appear unusually prone to violence, and violence is perpetrated at times by the far left. The present commentary should not be mistaken as an argument that acts of violence are necessarily related to conservative political ideologies, as extremism is motivated by many and complex factors. Our intention here is not to caricature individuals on the basis of their political values, but to summarize emerging evidence that natural selection shaped threat-processing mechanisms that psychologically distinguish left from right, generating somewhat distinct phenotypes evolved to function best within safe versus dangerous environments, respectively. These baseline differences in conservatives’ threat-reactivity, credulity and aggression appear alarmingly susceptible to exaggeration when subjected to the malign influence of propagandist media.

Read the full series “Extremism in Historical and Evolutionary Perspective”:

  1. Introduction by Anthony Lopez and Hammad Sheikh
  2. The Virtue of Extremism is its Enhancement of the Ordinary by David Barash
  3. Extremism as Defense by Rose McDermott
  4. Why Extremism Isn’t the Real Issue by Mark Sedgwick
  5. What is Radicalization? by Sophia Moskalenko
  6. Conservative Extremists Are Afraid of Threats That Don’t Exist by Colin Holbrook and Jennifer Hahn-Holbrook
  7. Extremist Violence Has Its Roots in Morality, Not Ideology by Clark McCauley
  8. In the Eye of the Beholder: Parochial Altruism, Radicalization, and Extremism by Zoey Reeve
  9. Hidden Figures: The Untold Story of Terrorist Recruiters by John Horgan and Katerina Papatheodorou
  10. Why Terrorists Are Misunderstood by Max Abrahms


  1. Miller, E. (2017). Ideological motivations of terrorism in the United States, 1970-2016. Retrieved from the National Consortium for the Study of Terrorism and Responses to Terrorism: https://www.start.umd.edu/pubs/START_IdeologicalMotivationsOfTerrorismInUS_Nov2017.pdf
  2. Jones, S.G. (2018). The rise of far-right extremism in the United States. Retrieved from the Center for Strategic and International Studies: https://www.csis.org/analysis/rise-far-right-extremism-united-states
  3. Koehler, D. (2019). Violence and terrorism from the far-right: Policy options to counter an elusive threat. Retrieved from the International Centre for Counter-Terrorism-The Hague: https://icct.nl/wp-content/uploads/2019/02/Koehler-Violence-and-Terrorism-from-the-Far-Right-February-2019.pdf
  4. 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. PLoS ONE, 13(12): e0208653. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0208653
  5. Hibbing, J.R., Smith, K.B., & Alford, J.R. (2014). Differences in negativity bias underlie variations in political ideology. Behavioral and Brain Sciences, 37, 297–350. https://motyl.people.uic.edu/NegativityBiasCommentary.pdf
  6. Osmundsen, M., Hendry, D., Laustsen, L., Smith, K., & Petersen, M. (2019, June 21). The Psychophysiology of Political Ideology: Replications, Reanalysis and Recommendations. https://doi.org/10.31234/osf.io/49hfg
  7. Cararro, L., Castelli, L., & Macchiella, C. (2011). The automatic conservative: Ideology-based attentional asymmetries in the processing of valenced information. PLoS One, 6, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0026456
  8. Dodd, M. D., Balzer, A., Jacobs, C. M., Gruszczynski, M. W., Smith, K. B. & Hibbing, J. R. (2012) The political left rolls with the good; the political right confronts the bad. Philosophical Transactions of the Royal Society of London, Biological Sciences. 367(1589), 640–49.
  9. McLean, S.P., Garza, J.P., Wiebe, S.A., Dodd, M.D., Smith, K.B., Hibbing, J.R., & Espy, K.A. (2014). Applying the Flanker task to political psychology: A research note. Political Psychology, 35, 831–840. https://www.jstor.org/stable/43783824
  10. Vigil, J.M. (2010). Political leanings vary with facial expression processing and psychosocial functioning. Group Processes and Intergroup Relations, 13, 547–558. https://doi.org/10.1177/1368430209356930
  11. Rozin, P., Royzman, E.B. (2001) “Negativity Bias, Negativity Dominance, and Contagion,” Personality and Social Psychology Review, 5(4), 296–320. https://www.wisebrain.org/media/Papers/NegativityBias.pdf
  12. Garcia, J., Hankins, W.G., & Rusiniak, K.W. (1974) “Behavioral Regulation of the Milieu Interne in Man and Rat,” Science, 185(4154), 824–831. https://science.sciencemag.org/content/185/4154/824.long
  13. Ito, T.A., Larsen, J.T., Smith, N.K., & Cacioppo, J.T. (1998) “Negative Information Weighs More Heavily on the Brain: The Negativity Bias in Evaluative Categorizations,” Journal of Personality and Social Psychology, 75(4), 887–900. http://dx.doi.org/10.1037/0022-3514.75.4.887
  14. Fessler, D.M.T., Pisor, A.C., & Navarrete, C.D. (2014). “Negatively-biased Credulity and the Cultural Evolution of Beliefs,” PLoS ONE, 9(4), e95167. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0095167
  15. Fessler, D.M.T., Pisor, A.C., & Holbrook, C. (2017). “Political Orientation Predicts Credulity Regarding Putative Hazards,” Psychological Science, 28(5), 651–660. https://journals.sagepub.com/doi/full/10.1177/0956797617692108?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed
  16. Hatemi, P.K., Funk, C.L., Medland, S.E., Maes, H.M., Silberg, J.L., … Martin, N.G. (2009). “Genetic and Environmental Rransmission of Political Attitudes Over a Life Time,” Journal of Politics, 71, 1141–1156. https://www.procon.org/sourcefiles/genetic-and-environmental-transmission-of-political-attitudes-over-a-life-time.pdf
  17. Loman, M.M., & Gunnar, M.R. (2010). “Early Experience and the Development of Stress Reactivity and Regulation in Children,” Neuroscience & Biobehavioral Reviews, 34(6), 867-876. https://doi.org/10.1016/j.neubiorev.2009.05.007
  18. VanTieghem, M.R., & Tottenham, N. (2017). “Neurobiological Programming of Early Life Stress: Functional Development of Amygdala-Prefrontal Circuitry and Vulnerability for Stress-Related Psychopatholog,” In E. Vermetten, D. Baker & V. Risbrough (Eds.), Behavioral Neurobiology of PTSD (pp. 117-136). Cham, Switzerland: Springer.
  19. Holbrook, C. (2016). “Branches of a Twisting Tree: Domain-specific Threat Psychologies Derive from Shared Mechanisms,” Current Opinion in Psychology, 7, 81-86. https://www.sciencedirect.com/science/article/pii/S2352250X15002006
  20. 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.
  21. Jost, J.T., & Amodio, D.M. (2012). “Political Ideology as Motivated Social Cognition: Behavioral and Neuroscientific Evidence,” Motivation and Emotion, 36, 55–64. http://dx.doi.org/10.1007/s11031-011-9260-7
  22. Holbrook, C., López-Rodríguez, L., Fessler, D.M.T., Vázquez, A., & Gómez. A. (2017). “Gulliver’s Politics: Conservatives Envision Potential Enemies as Readily Vanquished and Physically Small,” Social Psychological and Personality Science, 8, 670-678. https://doi.org/10.1177/1948550616679238
  23. Holbrook, C., López-Rodríguez, L., Gómez, 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. https://doi.org/10.1177/1948550617746219

Header image: “Gun rights advocates lobby,” Jan. 20, 2020 by VCU Capital News Service via Flickr

Published On: January 21, 2020

Colin Holbrook

Colin Holbrook

Colin Holbrook is an Assistant Professor of Cognitive and Information Sciences at the University of California, Merced. His program of research explores decision-making under contexts of threat, with particular focus on aggression, coalitional psychology, morality, and the attribution of mental states.

Jennifer Hahn-Holbrook

Jennifer Hahn-Holbrook

Jennifer Hahn-Holbrook is an Assistant Professor of Psychology at University of California, Merced who has published research in neuroendocrinology, developmental psychology, and threat assessment. Using interdisciplinary approaches, Dr. Hahn-Holbrook investigates how our rapidly changing world (in terms of technology, nutrition, employment patterns, etc.) impacts our mental and physical health.



  • Steve Davis says:

    Conservatism in its modern political form originated with Thomas Hobbes, who himself admitted (from memory) to an unnatural personal level of fear and anxiety.

    Hobbes’ believed that society is built on fear because each individual has base motives and acts lawfully only through fear of legal penalties. This erroneous belief permeates conservative thought! Ethical principles are actually the essence of social life, not fear. As we interact with others in our daily life, it’s ethical standards that provide us with the guidelines for a sociality that is mutually agreeable and productive. Social life can exist without fear but it cannot exist without ethics. Conservatism has side-stepped history and logic, making legal principles the foundation of civil society.
    Whenever the alleged virtues of conservatism and economic liberalism are trumpeted to the world it’s not ethics or decency or fairness that get a mention, it’s “the rule of law” and “property rights.” We can conclude therefore that there is no ethical basis to conservative/liberal thought, there is no conservative/liberal ethos.

    The really sad fact however, is that Hobbes’ dismal view of society, sick and twisted though it was, has become a self-fulfilling prophecy. The base, the suspicious, and the fearful, have a grip on power and are shaping the world in their own image. This is not mere rhetoric. Their unrelenting campaign against unionism is evidence not only of an acceptance of Hobbes’ false view of historical man, but of a wish and a striving for Hobbesian man! If conservatives/liberals were genuine in their concern for the alleged savagery of ordinary people they would see unionism as an evolutionary advance towards a state of harmony. Instead they see unionism as a threat to their class interests and prefer to see collective action eliminated and society accordingly weakened, to preserve narrow sectional interests.
    The conservative/liberal ideal is not one of harmonious development and social evolution, of voluntary association and mutual aid of the kind unions and other less formal groupings can give, their ideal is a fragmented society managed by an all-powerful state.

  • Rich says:

    The left/right psychological differences you describe could also be seen as stages of maturity where admitting the whole truth without getting defensive when your cultural beliefs are questioned is understood. Of course, here, the left is just as susceptible, once truths they are uncomfortable with are talked about. Threats are perceived when our cult-ural beliefs are questioned…. until we mature. The Holbrooks talk of

    ” .. the abiding distinction between conservatives, who prioritize the preservation of cultural traditions and the welfare of the in-group as safeguards against a world perceived as fraught with enemies, and progressives, who view change and between-group cooperation as beneficial opportunities in a world perceived as relatively safe.”
    But every group is made up of human minds that can choose to use narcissism and compassion in various ways. Humans mature to using more and more compassion because this agrees with our nature the most because we are social animals and compassion creates the best relationships where threats and stress are minimized. This is why we are egalitarian social animals. As humans mature, we realize that we can create social environments to be either threating or safe depending on whether we use narcissistic or compassionate, uncaring or caring mindsets. The advent of monarchies silenced compassion and permanently delayed human maturity.
    I just read a great article in the New Scientist by Deborah Rogers called “Inequality: Why egalitarian societies died out”. She ends with- “Although dominance hierarchies may have had their origins in ancient primate social behaviour, we human primates are not stuck with an evolutionarily determined, survival-of-the-fittest social structure. We cannot assume that because inequality exists, it is somehow beneficial. Equality – or inequality – is a cultural choice.” https://www.newscientist.com/article/dn22071-inequality-why-egalitarian-societies-died-out/
    I think cultural beliefs are the reason so many individuals do see equality as freedom- imagine there is a monopoly game where insecure landlords fight each other to collect money and forget about equality, and then also see reality where all humans want lasting respect and the only way to receive this from others is to live and act with a compassionate mindset that shares honor, equality and social justice. A compassionate mindset shares power with others. An immature mindset seeks fake power over others, like a king, and cannot be respected. A compassionate mindset understands reality where there is honor in being human. Narcissistic mindsets don’t know themselves, they are stuck in cultural beliefs that tried to silence human compassion many generations ago when monarchies formed and baboon temperaments corrupted modern egalitarian human neo-cortexes. Narcissistic mindsets have an insecurity that prevents them from seeing there is honor in being human- enculturation, being treated like a subject, and told they must improve their worth sparked fantasies of having superiority over others- so, they fight to defend the fake honor of their individuality, just like an immature king who doesn’t know how to receive real respect or honorable equality. Every cult-ure is a cult, some understand human nature and our drive for compassion and others create inequality, trauma and violence. Every empire fights the goodness in human nature and fails. So, are all men created equal or unequal? Cultural choice determines whether we live in truth, peace and well-being…or whether we suffer in lies, war, and stress. Calling out the conservatives might not be the best thing to do. Liberals are just a susceptible to using a narcissistic mindset in the monarch’s games of inequality we still play. All humans are trusting and gullible because we evolved being born into groups that care about us and tell us the truth. Monarchy changed this, and all modern cultures that stem from monarchy have been led by immature narcissistic mindsets that prey on their own people and lie to them domestically and about foreign policy. It’s easy to believe your culture is doing good things in the world, both the right and left make this mistake. They both have traditionally been told to see enemies who were really just people who were just practicing self-determination and trying to improve their well-being. Around 1900, the U.S. had a popular open debate about whether or not to be an empire on the global stage, Stephen Kinzer wrote a great book about this called The True Flag. Unfortunately, the imperialists won and decided to go “America first” everywhere. We chose to maximize corporate profits at the expense of the well-being of foreign civilians who we controlled through violence and puppet dictators. This was Teddy Roosevelt all left and right administrations since, including Hillary’s “American Exceptionalism”.

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