Abstract: Although most modern militaries go to great lengths to prevent their soldiers from losing their moral bearing, unlawful and unethical behaviour, and atrocities are widespread in war. Interestingly, such acts are commonly committed by groups rather than single individuals. The following paper explores the cognitive mechanisms at the heart of communal cruelty. It suggests that communal transgression of moral and social norms ultimately constitutes an integral part of human social cognition, facilitating in-group cohesion and loyalty. However, although we aim to understand how and why people commit acts of communal cruelty, we do not condone it or relieve the perpetrator(s) of responsibility for their actions. Instead, through an attempt to understand the cognitive mechanisms which may, under certain conditions, lead up to extraordinary communal cruelty, this paper aims to contribute to the development of tools to reduce the risk of such acts occurring.
Problem statement: How to explain severe communal transgressive behaviour and how to train officers and NCOs to prevent such acts by those under their command.
Bottom-line-up-front: Communal taboo-breaking behaviour is deeply rooted in human social cognition and accentuated under stressful conditions. However, given the right tools, leadership can mitigate or neutralise this tendency.
So what?: If we wish to limit the frequency and severity of severe communal transgressive behaviour, we should first understand it.
Ordinary People and Extraordinary Evil
On the 01st of April, 2022, the first images of the massacre of civilians in the Ukrainian town of Bucha reached popular news outlets. In little over a month of occupation, Russian troops of the 64th Motorised Rifle Brigade had killed at least 419 civilians, many bound before execution and mutilated. In addition, the Ukrainian Territorial Defence Forces, who liberated the town, found a torture chamber and Russian soldiers are reported to have raped girls as young as 14 years old. In 21st-century Europe, such atrocities were, until recently, seen as something from the past, and yet, Bucha was by no means an isolated incident. Similar reports have emerged following the liberation of Izium, Makariv, and Lyman; it is now safe to assume that more towns and cities in Russian-held territory have suffered a similar fate. The Russian authorities, for their part, deny any such event has occurred.
In little over a month of occupation, Russian troops of the 64th Motorised Rifle Brigade had killed at least 419 civilians, many bound before execution and mutilated.
Our inability to understand how anyone, no matter the circumstances, could inflict such horrendous acts of violence upon others often leads to attempts at conceptualising perpetrators of such acts as intrinsically different from ourselves by either singling them out as mentally compromised or designating them to an out-group that possesses an exceptional predisposition for brutality. Either way, they are not like us! They are motivated by evil to do evil; they take delight in the suffering they inflict upon others. The reality, of course, is far more nuanced, and most acts of extreme communal cruelty are rooted in the social context and/or ideological-political system in which they occur. In fact, as the German-born philosopher Hannah Arendt observes, most acts of extraordinary evil are committed by ordinary people, for ordinary reasons, and with ordinary means and are, therefore, "banal".
However, as this view suggests, if extraordinary communal cruelty is rooted in the ordinary, we are left with two inescapable premises: 1. The ability to inflict harm on others is innate to the human condition; and 2. this ability is only expressed under certain conditions. Unsurprisingly, most research in the field is centred around the conditions that enable extraordinary cruelty and is mainly concerned with what we will refer to as 'institutionally endorsed' (i.e., the local power structure actively sanctions, supports, or enables perpetrators in their actions) atrocities. Institutional endorsement amplifies the human capacity to inflict tremendous suffering on others in two distinct ways. Firstly, it facilitates higher levels of organisation and planning, which can prolong an ordeal and lead to the recruitment of larger groups of potential perpetrators. Secondly, it gives perpetrators the conceptual space to mentally dissociate from their actions. Each participant, from the autocrat who plans the logistics, to the propagandist who formulates the justification, to the executioner who pulls the trigger, becomes a cog in an institutional system and can thus downplay their personal responsibility. As such, one can play a central role in a genocide that kills millions without ever coming face to face with one's victims.
Each participant, from the autocrat who plans the logistics, to the propagandist who formulates the justification, to the executioner who pulls the trigger, becomes a cog in an institutional system and can thus downplay their personal responsibility.
Although less well studied, 'spontaneous eruptions' of extreme communal cruelty do occur (see, for instance, the Maywand killings, Afghanistan 2010 and the killing of civilians and prisoners of war by Australian Special Forces, Afghanistan 2005-2016), but lack the necessary bureaucracy to conduct large-scale and/or prolonged atrocities. However, because spontaneous eruptions require all members of the group, and especially the ringleaders, to actively engage, they demonstrate far more clearly that, in many cases, extraordinary communal cruelty is, at its core, a means to stimulate social bonding among perpetrators (see also the literature on gang-rape). As such, we postulate that this focus on the conditions which facilitate communal cruelty falls short just shy of the acknowledgement that extraordinary communal cruelty constitutes a universal tendency in human social cognition and, thus, very likely, amounts to a dysfunctional expression of an otherwise adaptive trait.
The Perpetrators and Their Crimes
Despite a general willingness, and often enthusiasm, to actively engage, the available, albeit limited, evidence suggests that most perpetrators of communal acts of cruelty know on some level, both during the act and post-factum, that their actions are morally unacceptable. Adolf Eichman, for instance, admitted during his trial in Jerusalem in 1961 that, even though he visited the extermination camps at Auschwitz, Treblinka, and Chelmno, as well as Minsk and Lviv during raids by the Einsatzgruppen, the sight of murder made him feel sick, and he avoided it as much as possible. Likewise, Wilhelm Trapp, a major in the German Reserve Police Battalion 101 (Reserve-Polizei-Bataillon 101), informed his men with tears in his eyes on the morning of the 13th of July 1942, that they were ordered to round up the Jewish population of the Polish town of Jozewof. Males of working age were to be separated and sent to labour camps, and the women, children, and the elderly were to be shot. Trapp proceeded to make the extraordinary offer to the older men in the battalion that those who did not feel up to the task could refrain from participation. Only 10 to 12 of the approximately 400 members came forward. In addition, one officer had asked to be excused from participation the night before. These men were assigned to different, yet still enabling, duties, while the rest carried out the murders as ordered. Some requested to be replaced after the first shootings, and many participants recounted afterwards how disgusted they were with themselves during and after their first mass killing. Similar sentiments have been reported by many of the men of Charlie Company (First Battalion, 20th Infantry Regiment, 11th Infantry Brigade, 23rd Infantry Division) after the My Lai Massacre, in which they killed between 347 and 504 unarmed civilians. For instance, Private First Class Paul Meadlo was ordered several times to kill groups of hurdled-together villagers. Reluctantly, and with great emotional strain, he executed the order and reportedly broke down in tears several times during the 4-hour-long massacre.
Adolf Eichman, for instance, admitted during his trial in Jerusalem in 1961 that, even though he visited the extermination camps at Auschwitz, Treblinka, and Chelmno, as well as Minsk and Lviv during raids by the Einsatzgruppen, the sight of murder made him feel sick, and he avoided it as much as possible.
This willingness to engage in communal acts of cruelty, despite the awareness that it is morally unacceptable, raises the question; why? Why, if the vast majority of perpetrators know that what they are doing is wrong, do they engage anyways? And why, moreover, if this sentiment is so widespread, does dissent not lead to decisive action? At My Lai, there were a handful of soldiers who refused to participate. Still, none in Charlie Company actively resisted, safe for corporal Ronald Grzesik, who intervened when a group of soldiers attempted to rape a young girl. However, he failed to secure her safety for long, and once he had turned his back, the girl was shot together with her mother, sister, and several children. In fact, the most decisive action that day was taken by the crew of an observation helicopter commanded by Warrant Officer Hugh Thompson jr. While flying overhead, they realised that something was wrong and managed to arrange the evacuation of some of the remaining villagers.
Certainly, some individuals, especially those who display dark triad (psychopathy, narcissism, and Machiavellianism) traits, tend to lack basic levels of empathy. Moreover, these traits, especially psychopathy, have been associated with higher levels of (sexual) sadism. However, these individuals make up just 1-4.5 per cent of the general population. They can hardly account for the actions of the majority of individuals who commit communal acts of cruelty. Even if we assume that the military disproportionately attracts or recruits individuals who portray a tendency towards the dark triad (to our knowledge there is one study suggests that the prevalence of anti-social personality disorders, which includes the dark triad, might be twice as high in the military compared to the general population), it is statistically improbable that a military unit constitutes, by accident, 80 per cent or more individuals with a serious tendency for sadism and a severe lack of empathy. Let alone that such a unit would make it through basic training without anyone noticing. However, these individuals may be disproportionately involved in instigating transgressive behaviour; especially psychopathy has been associated with higher tendencies to engage in wartime atrocities. Still, the higher presence of individuals with anti-social personality disorders in the military does not explain the engagement in communal cruelty of neurotypical soldiers.
Even if we assume that the military disproportionately attracts or recruits individuals who portray a tendency towards the dark triad, it is statistically improbable that a military unit constitutes, by accident, 80 per cent or more individuals with a serious tendency for sadism and a severe lack of empathy.
Moreover, in some cases, people high on dark triad traits are considered detrimental to efficiency and too unreliable by organisations, which either engage in or enable communal acts of cruelty. The SS Einsatzgruppen, for instance, would commonly prefer neurotypical, psychologically healthy individuals and actively selected against individuals with a tendency towards sadism or psychopathy. As such, although individuals with anti-social personality traits may facilitate communal acts of cruelty, they are too few to account for the high levels of engagement commonly observed among perpetrators.
Interestingly, there is some evidence that suggests that head injury may precipitate diminished empathy. Although exact statistics are hard to come by, it is safe to assume that front-line military personnel runs a greater risk of head trauma. It is, however, unclear how such trauma interacts with stress and psychological trauma and whether its effects are permanent or transient. Moreover, decreased empathy does not necessarily entail increased cruelty and, as such, seems a prerequisite for cruel behaviour rather than an indicator. Similarly, there are some indications that psychological trauma may negatively affect empathy. However, the available evidence relates largely to post-traumatic stress disorder, a mental disorder which is commonly diagnosed at least six months after the traumatic experience. As such, it is unclear how psychological trauma affects empathy in the short term. Moreover, in many cases, communal cruelty precedes the trauma rather than causing it.
One explanation, which is often cited by perpetrators post-factum, is a fear of repercussions, and there certainly seems to be an element of in-group control on commitment. Such repercussions may range from being killed oneself to future negative consequences or social ostracisation. As far as we know, there is limited evidence, apart from the Rwandan genocide, that explicit threats against abstainers' lives are common. However, especially in a military context, the availability of lethal weapons and the general danger involved in operations may contribute to such fears, even if the threat is not made explicit. Moreover, non-compliers often find themselves on more dangerous missions in the wake of communal cruelty. As such, the threat is often there, even if it is not explicitly voiced.
More common are explicit threats of future consequences. Most mass atrocities, and thus by extension, the more severe acts of communal cruelty, occur in a military or para-military context. As such, the context and structure to both reward and punish (non-)compliance are readily in place. At My Lai, for instance, Lieutenant Calley threatened several soldiers with court-martial, when they disobeyed orders to shoot unarmed civilians. On the other hand, throughout the Vietnam war, the 'body count' indicated a soldier's chances of promotion, which may have influenced some at My Lai to see an easy way to self-advancement. As such, opportunities to advance or degrade one's professional position are closely tied to one's willingness to engage in institutionally endorsed transgressions.
At My Lai, for instance, Lieutenant Calley threatened several soldiers with court-martial, when they disobeyed orders to shoot unarmed civilians.
In addition, institutional endorsement often provides the logistics, means and formal justification (i.e., ideology) to carry out prolonged large-scale atrocities. As such, one does not necessarily need to be a firm believer in the ideology on which the transgression is based. Pragmatic acceptance of its basic premises often suffices. Only 25 per cent of the men serving in Reserve Police Battalion 101, for instance, were members of the Nazi party. Moreover, they were recruited into the Reserve Police because they were considered too old for the regular army (the average age was 39) and thus had their formative years in pre-nazi Germany, came from a social class which traditionally leaned more communist or socialist. Most came from Hamburg, one of the least Nazified cities in Germany. Although hard data about their ideological beliefs are unfortunately unavailable, it is not likely that these individuals were hard-core believers in Nazi ideology. Yet, they managed to be directly or indirectly involved in the murder of 83.000 Jews, making them part of the most deadly police battalions of the Holocaust.
Finally, institutional endorsement offers participants the conceptual space to dissociate from the harm they cause by diffusing responsibility over the system or situation. Firstly, any prolonged, large-scale, coordinated action requires a certain level of planning and bureaucracy. As such, behind the actual killers stands a cadre of individuals who enable and coordinate their actions. As mentioned above, Eichman probably never killed anyone personally, and yet, aside from Hitler, he probably bears more responsibility for the Holocaust than anyone else. Eichman is not unique in this regard. For many men involved in planning, justifying, and facilitating the Holocaust, it was a bureaucratic or ideological exercise rather than the systematic murder of millions of people. They were, in a sense, divorced from the suffering they were causing even though their guilt, it can be argued, far exceeds that of the camp guards, members of the SS and the auxiliary forces who carried out the murders.
However, the space to diffuse responsibility over the larger community of perpetrators or the organisation which endorses the transgression extends to the killers as well. During the Rwandan Genocide in 1994, Hutu perpetrators attacked their Tutsi compatriots with machetes and rifles. In many cases, the perpetrators and victims lived in the same villages and knew each other well. They came from the same communities and went to church together. Yet, despite this close social and physical proximity, the Hutu genocidaires killed approximately half a million Tutsi within the first 100 days, making it one of the most efficient and brutal genocides in recorded history.
During the Rwandan Genocide in 1994, Hutu perpetrators attacked their Tutsi compatriots with machetes and rifles.
Institutional endorsement, and thus formal space to diffuse responsibility, is not always explicit and often retracted retrospectively. Many of the American GIs involved in the massacre at My Lai believed they were expected to kill indiscriminately and reference this as one of the main reasons for their brutality. Subsequent investigations by the United States Army led to the conviction of Lieutenant William Calley, even though he was neither the highest-ranking officer on the ground nor the only soldier engaging in the killing. In truth, few refused to participate, and none in Charlie Company seriously attempted to stop it. Although it is unclear what led the men to carry out the massacre, the presence of command helicopters overhead suggests that the destruction of My Lai, including its civilian population, might have been part of the contemporary US counterinsurgency strategy. Similarly, there are indications that the torture sessions inflicted on prisoners by US soldiers at the Abu Ghraib prison in Iraq in 2004 were, if not instigated, at least supported and tolerated by higher command as a means to aid intelligence gathering.
In response to these and other atrocities, social psychologists have sought to shed light on the underlying psychological mechanisms and have identified authority, social conformity, and fear of in-group retribution as potential pressure points once the transgression has commenced. However, non of these mechanisms explain why groups gravitate towards transgression in the first place. The Stanford Prison Experiment has yielded a host of information and theories about the acceleration of transgression but remarkably little on its instigation. To date, this has been the only somewhat controlled experiment into the dynamics of communal transgressions against widely accepted ethical norms. In it, participants (all male students at Berkley University with no indications of mental disorder) were randomly assigned to either be prison guards or prisoners. The experiment was supposed to take two weeks but had to be terminated after only five days because of the severe mistreatment of prisoners by the prison guards. Although based on newly uncovered materials, it has recently been argued that the experimenters probably played a more significant role in instigating the abuse than previously thought. However, participants in the experiment knew that they were under no obligation to carry out any directive from the experimenters and could, at any moment, terminate their participation.
The Stanford Prison Experiment has yielded a host of information and theories about the acceleration of transgression but remarkably little on its instigation. To date, this has been the only somewhat controlled experiment into the dynamics of communal transgressions against widely accepted ethical norms.
Moreover, they had been screened for markers of mental disorders, and there was no indication of a higher affinity to sadism in any of them. So, even if they were urged to mistreat the "prisoners", they could have objected but chose not to. Encouraged or not, they took the first and following steps towards inhumane behaviour.
Moreover, in the absence of explicit institutional endorsement, acts of extreme communal cruelty, albeit on a smaller scale, unfortunately, occur with shocking regularity. Although one could point to in-group dominance structures as a substitute for institutional endorsement, it must be noted that this would require the individuals who make up these structures to instigate, accelerate and actively participate in the brutality.
During the Maywand killings, a group of 12 US servicemen deployed in the Maywand district in Afghanistan styled themselves the "Afghan Kill Team". This group engaged passively (seven were involved in the cover-up but not the killing itself) or actively in the thrill-killing and subsequent mutilation of at least three Afghan civilians. In at least two of the three known cases, the perpetrators used captured weapons to hide the fact their victims were unarmed non-combatants. Such actions indicate that these men were aware that what they did was wrong and would get into serious trouble if found out. However, at the same time, they took photographs of themselves posing with the bodies and sometimes took body parts as souvenirs.
Incidents like the Maywand killings indicate that although the institutional, hierarchal, and ideological context can undoubtedly play a prominent part in shaping acts of extreme communal brutality, it is unlikely that they constitute the psychological bedrock which underlies the tendency of groups to inflict harm on others. Instead, this tendency can best be understood as a dysfunctional expression of transgression and secrecy dynamics. A greater understanding of these dynamics and the conditions under which they can become dysfunctional may thus aid in mitigating the likelihood and severity of acts of extreme communal brutality.
Secrecy and the Social Value of Transgression
Minor infractions of commonly held norms are incredibly common, as is the willingness to divulge information about those infractions selectively. At first glance, this is paradoxical; surely, if a certain bit of information is worth concealing, its revelation would be detrimental to the transgressor. To account for this paradox, it is traditionally assumed that humans are inherently moral beings and that they, therefore, struggle to conceal information intentionally. Secrecy, thus, coevolved with stigmatisation and enables individuals to, at least temporarily, conceal certain undesirable traits, knowledge of which may constitute a challenge to their position within the social group. Initially, this position was corroborated by studies into deceit, of which secrecy forms a sub-category, which suggests that being truthful leads to less cognitive strain than lying. However, these studies compared truthfulness and deceit under neutral conditions and did not take the roles of social and psychological pressures into account. Accordingly, when this was corrected for in subsequent experiments, the choice depended on an ad hoc cost-benefit calculation (i.e., the cost of being truthful set off against the convenience of lying within the specific context) rather than an innate desire or drive to be truthful.
Minor infractions of commonly held norms are incredibly common, as is the willingness to divulge information about those infractions selectively.
As such, secrecy, in both content and outlook, is quite distinct from self-concealment. The latter refers to "a predisposition to actively conceal from others personal information that one perceives as distressing or negative"  and generally involves the fear of stigmatisation. Hence, self-concealment often occurs in relation to trauma, illness, mental health issues, family matters, personal insecurities, and sometimes severe transgressions of social norms. As such, not only the content but also the existence of that content is consciously concealed. On the other hand, secrecy refers to information which is concealed, while its existence of said information is not, and may even be, actively propagated. As such, secrecy is, first and foremost, a social phenomenon, and both revelation and concealment are aimed at a target audience. The choice to reveal or conceal information can, thus, best be understood as a social strategy and depends largely upon whether or not the secret keeper perceives the potential receiver as both willing and able to use the information to the detriment of the revealer. Secrecy, thus, beyond the potential transmission of information, secrecy (i.e., the act of either revealing or concealing information) constitutes a means of social communication.
Because of this social component, secrets commonly comprise specific information types. The most common and most important to the current discussion are relatively minor infractions of commonly held social and moral norms. Because of the social nature of secrecy revelations, these transgressions can neither be too trivial nor too serious. Few would, for instance, be comfortable receiving information about a murder, let alone keeping that information concealed. Secondly, secrets may contain information that provides the keeper with a social or economic advantage over others. This information may pertain to transgressions by others, perceived innovations, or ongoing political processes (i.e., state and corporate secrets). Importantly, the information that makes up the content of these secrets does not reflect negatively upon the revealer, even if the act of revealing it may.
The communication of secrets follows a relatively strict set of rules, a grammar, in which, if successful, the secret keeper and receiver enter into a "social contract". Firstly, by revealing the information, the secret keeper relinquishes control and, thus, power over the information in favour of the receiver. Even though the receiver is expected to retain secrecy, what they do with it, is ultimately up to them. The act of revealing this information thus signals trust and a desire to deepen relations, and further dissemination of the information by the receiver usually constitutes a breach of that trust. It is therefore not surprising that even if the receiver of secret knowledge is not made explicitly aware of the secret nature of the information revealed to them, most instinctively understand, though not necessarily respect, the secret nature of the information.
The act of revealing this information thus signals trust and a desire to deepen relations, and further dissemination of the information by the receiver usually constitutes a breach of that trust.
On the other hand, the receiver signals a similar desire and understanding by receiving the information and retaining secrecy. Moreover, because many secrets involve personal transgressions of commonly held social norms, the receiver is expected to refrain from judging the secret keeper based on the revealed information. A refusal to receive secret information thus communicates as much of an unwillingness to interact with the secret keeper, as the unwillingness to reveal.
As a consequence, human social groups are infused with lots of interpersonal connections in which everyone has some information on some others, but no one knows everything about everyone. As such, secrecy allows individuals to demonstrate their loyalty to and investment in the group without facing the judgment of said group. Furthermore, people who conceal or reveal too much and people who never transgress against the norms, are often mistrusted or disliked their lack of secret-sharing limits the strength of the connections they can make. In addition, because secrecy serves as a means to signal in-group investment and loyalty, the willingness to reveal and the risks one is willing to take to over-share increases as the need for in-group affiliation rises. Consequently, high-stress environments should be expected to invite the revelation of more severe social norms transgressions. Moreover, these revelations are aimed predominantly at individuals whom the keeper perceives as similar or superior on the social hierarchy.
Communal transgressions of social norms differ substantially from individual infractions in that the group as a unit engages in the norm-violating behaviour. Consequently, if one of the group opts to divulge the information to a third party, they do so to the detriment of themselves and all in-group members. As such, communal transgressions require extra controls on dissemination, which is in part achieved through mutual engagement. Mutual engagement signals loyalty to the group by taking on an equal share of the responsibility and, thus, an equal investment in sustained concealment. However, it is often impossible to precisely quantify the transgression, let alone replicate it, and so, the severity of transgression can quickly accelerate as in-group members vie to demonstrate in-group involvement and loyalty. The men of the Reserve Police Batallion 101, for instance, felt such an obligation towards their comrades to participate that those who could not bring themselves to kill would decades later still ascribe this inability to weakness rather than moral considerations for the wellbeing of their victims.
Mutual engagement signals loyalty to the group by taking on an equal share of the responsibility and, thus, an equal investment in sustained concealment.
Of course, shared responsibility for communal transgressions, based on mutual engagement, which are carried out within a strict hierarchal structure, like the military, is mitigated by the different positions transgressors occupy in said hierarchy. An officer who orders a unit to carry out an atrocity, it could be argued, bears more responsibility for it than the soldier who carries out said order. At My Lai, for instance, Lieutenant Calley threatened to have some of the soldiers in his platoon who refused to partake in the murders court-martialled, and Captain Medina encouraged his men in the aftermath of the massacre to refrain from commenting on it. In addition, he approached at least one soldier, Michael Berhardt, personally to warn him not to write to his congressman about the massacre. Bernhardt was one of the soldiers who refused to participate and thus had little incentive to keep the massacre secret. Although he claimed not to have discussed any plans to attract attention to the massacre with anyone, his refusal to participate and a history of contacting authorities was enough for Medina to make his thinly veiled threat. Had Bernhardt actively participated, his involvement may have been perceived as sufficient to deter him from contacting outside authorities. As such, despite differences in responsibility due to hierarchal positions, at a certain point, the level of engagement exceeds the norms to such an extent that any differences become —at least on an emotional level— almost academic.
The extent to which individuals are willing to engage in communal transgressions is thus tied to their psychological need for in-group safety, which in turn depends on their perception of both the group and the wider context. Under uncertain or highly stressful conditions, the incentive to engage thus increases. Where individual transgressions are not meant to shock, communal transgressions depend, in as far as they signal loyalty to the group, on a willingness to transgress past commonly accepted limits. Moreover, because the direct peer group collectively engages in transgressive behaviour, there are few social cues that one is involved in unacceptable conduct. From the perpetrator's perspective, their concerns about their actions and those of other in-group members do not seem shared to the same extent by the group. This further lowers the threshold to engage, even if one knows it is incorrect. As such, military personnel is uniquely set up for the perfect storm; they are confronted with highly stressful and dangerous situations, depend heavily on each other (the in-group) for survival, and are equipped with the means to cause serious harm.
The Unknown Hero: Those Who Resist Human Nature
Unfortunately, remarkably little is known about instances in which individuals prevented an atrocity from occurring. Not because this rarely happens, but rather because if an issue has been prevented from reaching its logical conclusion, then nothing has happened and thus, there is no incident to report. Therefore, we are confronted with a reverse survivor bias. Only those cases in which things go terribly wrong are reported, which provides us with a wealth of information on the ugliest side of human nature. Yet, we lack sufficient direct evidence on prevention. However, given the number of wars fought worldwide, we should expect far more mass atrocities. That they do not, or that we do not learn of them, may be partially down to successful cover-ups or a lack of interest (the best-kept secrets are, after all, "those that no one really wants to know"). However, in a world in which everyone has a camera on their phone and ready internet access, it has become increasingly difficult to cover up extreme, large-scale communal transgressions. The mistreatment of prisoners at Abu Ghraib, the Maywand killings, and, more recently, the war crimes of Russian soldiers in Ukraine have all been partially documented photographically by perpetrators, who shared this material with others. As such, all else being equal, we should expect a stark increase in reported cases. This disproportionately affects the militaries of more affluent (i.e., with easier access to modern communication technology) nations. To our knowledge, this is not the case.
Only those cases in which things go terribly wrong are reported, which provides us with a wealth of information on the ugliest side of human nature. Yet, we lack sufficient direct evidence on prevention.
Sometimes resistance comes in the form of an out-group member or an in-group member who is divorced from the act for one reason or another and intercedes. In the My Lai massacre, for instance, a US helicopter commander, Warrant Officer Hugh Thompson Jr., intervened. Upon realising what was happening, Thompson confronted the officers and later the enlisted men of Charlie Company while he began arranging the evacuation of civilians. His bravery, and that of the two men under his command, saved the remaining villagers and brought the massacre to the world's attention. Likewise, although on a much less dramatic scale, when psychologist Christina Maslach was brought in to evaluate the Stanford Prison Experiment, she was appalled by what was happening and convinced the principal researcher, Philip Zimbardo, to put an end to the experiment. However, given that such instances require the presence of an out-group or semi-out-group member willing and able to intercede on behalf of the victims, they are probably relatively rare.
As such, the most likely source of resistance derives from within the in-group. Interestingly, although Solomon Asch's classic studies into conformity are often referenced as evidence for the tremendous effect in-group dynamics have on human perception, one variation of his experiment demonstrated how one dissenting voice can largely offset the effect. However, in Asch's experiments, stress levels and the need for in-group security were relatively low. In more challenging conditions, a dissenting voice seems to have less of an impact if it is only concerned with a refusal to engage. One of the prison guards in the Stanford Prison Experiment refused to engage in the abuse but was not followed by his fellow guards. Likewise, there were those within Charlie Company in My Lai and Reserve Police Batallion 101 in Poland who refused to participate without their objections having had much of an effect on other members of their respective units. As such, resistance under these conditions likely requires a more proactive stance. After all, one needs to offset both the effects of in-group conformity and the need for safety within the group.
Although there is, to our knowledge, no direct evidence to support the notion that proactive resistance against communal brutality can be "contagious" (i.e., can lead others to object as well), there is reasonable circumstantial evidence to suggest this is indeed the case. Firstly, a follow-up to the classic Asch paradigm found that most participants did not conform because they believed the position of the group to be more correct than their own. Similar sentiments are found in the accounts of perpetrators of communal brutality; many engage while knowing on some level that what they are doing is unacceptable. Although some believe that, what they are involved in, is morally correct, this is a minority, and any communal action ends or never commences when a critical mass within the group proactively opposes the group's activities. As such, any strategy to diminish the likelihood of extreme transgressions has to be aimed at those in the group who know that the infraction is highly immoral but do not act upon it.
Although relatively little is known about predictors of "reluctant conformers", neurological studies into conformity suggest a rise in activity in the amygdala upon confrontation with a factually "wrong" answer by the current in-group. This brain region is strongly associated with stress-response and prediction error. Therefore, it is unsurprising to see activity in this region rise among those who feel uncertain in response to conflicting perceptions with the group. Moreover, individuals with a higher affinity for psychopathy, i.e., less susceptible to in-group dynamics, do not display equal elevations of activity. In contrast to this, those who conform and fully embrace the position of the in-group, beyond displaying elevated amygdala reactivity, demonstrate raised activity in the hippocampus (a region primarily associated with memory) and the visual cortex, which indicates a retrospective reevaluation of memory and perception. In a real sense, they grew to believe the false information to be true. As such, at least for reluctant conformers, resistance to in-group pressure and amygdala reactivity should be correlated and resilience training for military professionals should, hence, incorporate protocols that lower the effects of in-group pressure on amygdala reactivity and the stress response in general.
Although relatively little is known about predictors of "reluctant conformers", neurological studies into conformity suggest a rise in activity in the amygdala upon confrontation with a factually "wrong" answer by the current in-group.
Exactly how this can be accomplished, given the high-stress context in which military professionals operate, remains, at least to our knowledge, unclear and more research is warranted. There are some interesting avenues of study, including the effects of leadership on endorphin function in subordinates and the effects of a "designated confidant" (i.e., an individual who is explicitly tasked with taking the moral position in a unit's actions to ensure the conceptual space for resistance. In addition, providing officers lower down the ranks and non-commissioned officers with higher levels of autonomy may limit the conceptual space for the diffusion of responsibility. However, at present, all these approaches are based mainly on speculation. As such, this paper should be read as an attempt to explore the next step in investigating atrocity prevention rather than providing concrete recommendations.
Most research into extreme communal cruelty revolves around the conditions which make it possible. Given the scale and frequency of genocide in the previous century, it is unsurprising that, in particular, institutionally endorsed atrocities have been awarded a lot of attention. In this paper, we explored the cognitive basis for extreme communal cruelty instead and have identified a possible mechanism through which otherwise moral individuals can find themselves engaging in unspeakable acts of violence. Rather than a symptom of mental dysfunction or indoctrination, we argue that communal transgressions of commonly held social norms are rooted in human social cognition and in-group cohesion. However, where individual infractions of the norms are naturally limited in their expression (if they are to serve a social function), communal transgressions are far less constrained. As such, especially in high-stress contexts, such as those faced by military professionals, the need for in-group security, and thus the willingness to engage in communal transgressions and accelerate their severity, rises substantially. Extreme communal cruelty can, therefore, be understood as a dysfunctional expression of human social cognition under extreme conditions. Any attempt at curtailing such events should, therefore, be aimed primarily at the mechanisms behind in-group membership and the stress which comes with potential exclusion. Such targeted curtailment becomes especially pertinent when one considers that often, acts of conformity do not equate to a personal agreement with the group, just a willingness to go along with the group's judgement in favour of one's own.
Rather than a symptom of mental dysfunction or indoctrination, we argue that communal transgressions of commonly held social norms are rooted in human social cognition and in-group cohesion.
Finally, we would like to caution the reader that this paper and its thesis are in no way a defence of the indefensible. On the contrary, because most involved know that the transgression is unacceptable, it likely takes a few in-group members to actively oppose it to keep in-group signalling dynamics from running out of control. The tendency to yield to perceived in-group pressure can be significantly mitigated by as little as one dissenting voice. In a genuine sense, in the face of the worst that humankind has to offer, each individual becomes responsible for both their own acts and those of all others in their in-group. The massacre at Bucha, and all those preceding and following it were not inevitable. Attempting to understand the mechanisms behind communal cruelty does not justify or condone such behaviour or relieve perpetrators of their responsibility. However, it may help in avoiding, mitigating the severity of, and predicting future occurrences.
Although instances in which groups are effectively kept from engaging in extreme violence rarely reach front-page news, the fact that the introduction of modern communication technologies did not notably raise the instances of reported misconduct in modern, western-trained militaries suggests that proper training and leadership as well as care for deployed soldiers, may strongly mitigate the probability of extreme communal transgressions occurring.
David William Mac Gillavry, Ph.D. is an assistant professor at the Department of Leadership (Faculty of Military Leadership, Czech University of Defence). His research focuses on the evolutionary, cognitive and physiological foundations of human behaviour under extreme conditions.
Zdeněk Mikulka, Ph.D. is an assistant professor for the Department of Leadership at the Czech University of Defence. He specialises in applied (military and security) ethics. Within the framework of military and security ethics, his research focuses primarily on processes of moral judgments and moral decision-making and the issue of bellum iustum.
First Lieutenant Ing. Jakub Stříbrný is a former member of a Czech airborne battalion and a Ph.D. candidate at the Czech University of Defence. His research is mainly concerned with stress management under extreme conditions and combat leadership.
The views contained in this article are the author's alone and do not represent the views of the Czech University of Defence.
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 Louisa Loveluck et al., “In Bucha, the Story of One Man’s Body Left on a Russian Killing Field,” The Washington Post, April 16, 2022, https://www.washingtonpost.com/world/interactive/2022/bucha-atrocities-civilian-killings/; Max Bearak and Louisa Loveluck, “In Bucha, the Scope of Russian Barbarity Is Coming into Focus,” The Washington Post, April 6, 2022, https://www.washingtonpost.com/world/2022/04/06/bucha-barbarism-atrocities-russian-soldiers/.
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 Former United States Sevcretary of Defence, Donald Rumsfeld, for instance, referred to the guards at the US-run Abu Graib prison, who were involved in the torture and humiliation sessions of prisoners, as “un-American” and “a few bad apples” (see: Kersten, Astrid, and Mohammed Sidky. “Re-Aligning Rationality: Crisis Management and Prisoner Abuses in Iraq.” Public Relations Review 31, no. 4 (2005): 471–78. https://doi.org/10.1016/j.pubrev.2005.08.003; Smeulers, Alette, and Sander Van Niekerk. “Abu Ghraib and the War on Terror - A Case against Donald Rumsfeld?” Crime, Law and Social Change 51, no. 3–4 (2009): 327–49. https://doi.org/10.1007/s10611-008-9160-2). Similarly, the My Lai massacre was at the time often ascribed to a few rouge soldiers, and accordingly, only one, Lieutenant Calley, got sentenced for his involvement (see: Gray, Truda, and Brian Martin. “My Lai: The Struggle Over Outrage.” Peace & Change 33, no. 1 (2007): 90–113. https://doi.org/10.1111/j.1468-0130.2007.00477.x.).
 For an excellent review and critique of perpetrator profiles as well as an intuitive understanding of them, see: James Waller, Becoming Evil: How Ordinary People Commit Genocide and Mass Killing (Oxford: Oxford University Press, 2002), https://doi.org/10.1001/jama.300.6.737.
 In this paper, we do not address extremely violent acts perpetrated by individuals. We recognise, of course, the existence of pathologies such as psychopathy, sociopathy and narcissism, which may predispose individuals to violent behaviour. Here, however, we are solely concerned with communal acts of extreme cruelty.
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 In the high-intense violence fuelled conditions associated with many atrocities committed during wartime, the threat of suffering is ever present and, at times, explicitly expressed. Several participants of the Rwandan genocide, for instance, attest that they were given the choice between killing or being killed. See: Waller, Becoming Evil: How Ordinary People Commit Genocide and Mass Killing.
 Some of those who refused to participate in the My Lai massacre were threatened by Leutenant Calley with a court martial for disobeying orders. In addition, warrant officer Thompson got sent on increasingly dangerous missions after he submitted his report about the massacre. See: Jones, My Lai: Vietnam, 1968, and the Descent into Darkness.
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 See, for instance, non-compliers at My Lai: Jones, My Lai: Vietnam, 1968, and the Descent into Darkness, 343.
 Waller, Becoming Evil: How Ordinary People Commit Genocide and Mass Killing, 191.
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 for an excellent analysis of the Rwandan Genocide, see: Waller, 2008.
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 Many of the soldiers who served in Charley Company certainly believed that the order to destroy everything at My Lai came from a higher authority than their company commander. See: Jones, My Lai: Vietnam, 1968, and the Descent into Darkness, 181.
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 According to Michael Bernhardt in his testimony before the Peers committee in 1970; See: Olson and Roberts, 123.
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 I.e., individuals who know that what they are doing is wrong but engage anyways to avoid friction with the group.
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 At present, there is not enough data to assume causation.
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 We are not the first to address this issue. A similar point was made very effectively in: Hannah Arendt, Eichmann in Jerusalem: A Report on the Banality of Evil (Penguin Books, 2006), and: James Waller, “Perpetrators of Genocide: An Explanatory Model of Extraordinary Human Evil,” Journal of Hate Studies 1, no. 1 (2002): 5, https://doi.org/10.33972/jhs.2.