What can neuroscience tell us about violent extremism? As a cognitive scientist who was part of the team that conducted the first ever set of brain scans of a radicalised population (that is, jihadist supporters), this is a question I encounter at conferences, during webinars and via social media posts. Often the question is meant rhetorically. Some social scientists have even accused me of conducting phrenology, a defunct discipline from the 19th century that is best known for looking at bumps on human skulls to make unfounded conclusions about the intellectual inferiority of certain ethnicities. My answer, if I choose to give one, is that neuroscience has much to contribute to our scientific understanding and in terms of offering practical insights. Moreover, these contributions are complimentary to rather than in competition with social and behavioural sciences.

In my experience, most social scientists and policy experts specialising in security-related issues fall on two ends of a spectrum when presented with neuroscientific data. One group is repulsed, at worst calling such research “Nazi science” or at best showing extreme scepticism about the encroachment of life sciences on what they see as something that should fall squarely within the purview of the social sciences. The other, much larger group takes the opposite position, displaying a bizarre fealty to colourful pictures of the human brain and showing a willingness to dismiss everything that they previously believed in order to usher in the findings from a “real science”.

Of course, both ends of this spectrum are overreactions. Neuroscientific research will always be subordinate to the social and behavioural sciences. It is the observations from such fields as sociology that allow neuroscientists to infer what must be going on inside the human brain given what we see at a social scale. Meanwhile, social neuroscience is largely a field that takes well-tested social psychology experiments and tries to replicate them inside things like brain scanners. Neuroscientific data is nothing more than an extra source of information that can help us to triangulate, along with social and behavioural science data, the causes of violent extremism and potentially lead to solutions as to preventing and countering them.

Rational Actors Versus Devoted Actors

So, how does neuroscience work hand in glove with the social and behavioural sciences to explain violent extremism? Much of social science research looks at war and violent conflict through the lens of rational actor models. These are models positing that people make decisions by weighing self-interested advantages and disadvantages of a particular action. From this perspective, if the pros outweigh the cons, it is then rational to go to war, join a terrorist group, start an insurrection and so on.

While rational actor models certainly explain a lot, they are insufficient at explaining the data on radicalisation, the process by which someone’s mind changes to increase their likelihood of committing political violence. Many of those who join terrorist groups leave behind comfortable, secure and materially pleasurable existences to put their lives at risk in war-torn regions of the world. They are not being rational in a self-interested way; rather, they are being group- and value-interested. We call these people devoted actors: people who are willing to make extreme, costly sacrifices (including fighting and dying) for their primary identity group and their sacred values.

The concept of sacred values has been well developed in anthropology, sociology, political science and psychology. They are a subset of moral values that do not conform to instrumental (that is, reward and punishment) decision-making. In other words, adherence to sacred values cannot be explained using rational actor models. Instead, it seems to be a fundamental element of devoted actors. My colleagues and I wanted to see how peer-group dynamics interacted with sacred values to increase or decrease a radicalised person’s willingness to fight and die. In essence, we wanted to pinpoint how peer-group dynamics can move people closer to and further from violence, to inform counter-radicalisation programmes.

Social Exclusion Pushing Extremists Towards Violence

To do this, we ran two neuro-imaging studies on jihadist supporters in Barcelona. Spain regularly ranks among Europe’s top nations for recruitment into jihadist groups and the Barcelona region is the country’s primary hotspot for radicalisation. In the first study we wanted to look at what made people at the early stages of radicalisation move towards violence. We know from decades of social and behavioural science research that social exclusion can push people towards nefarious groups, such as gangs, cults and extremist movements. In this context, we wanted to see how a sample of Moroccan diaspora men who held jihadist sympathies would react if they were excluded by non-diaspora Spaniards.

Out of a pool of 535 surveyed respondents from the Moroccan diaspora community, we recruited 38 early-stage radicals who said that they would engage in violence in defence of issues championed by jihadist groups (such as the enforcement of strict sharia law across all Muslim countries, armed jihad against the West and so on). After being screened for normal IQs and mental health disorders, the Moroccan participants played a virtual game with three ostensibly Spanish players that involved tossing a ball. For half the participants, after a few attempts, the Spanish players stopped passing the ball to the early-stage radicals and kept passing it among themselves (what the study considered a “social exclusion condition”). For the other half, the other players kept passing the ball to our participants (this was the “control condition”). All participants then entered the scanner and viewed multiple values that were either sacred or non-sacred to them, as ascertained beforehand using psychometric tools. They also evaluated their willingness to fight and die for each value.

We found behavioural and neural evidence that social exclusion moves values from the non-sacred category into the sacred one. Specifically, we found that participants who were socially excluded had areas of the brain (in particular, the left inferior frontal gyrus) that normally activates for sacred values (as evidenced in two previous studies) now activated for non-sacred values. Participants even started behaviourally stating that previously non-sacred values were now sacred. Additionally, the socially excluded participants explicitly increased their stated willingness to fight and die for their non-sacred values and made them comparable to sacred values. This is a worrying finding as this means these individuals were becoming more devoted actors. Standard rational actor persuasion techniques (such as carrots and sticks) will thus become less effective.

Social Norms Pulling Extremists Back From Violence

How do you persuade a devoted actor off the path of violence? In the previous study, we showed how social exclusion from an out-group can move in-group members who hold extremist sympathies towards violence. Next, we wanted to see how non-extremist in-group members can pull their extremist peers back from violence. To do this, we conducted a second study where we surveyed 146 Pakistani men in the Barcelona region and found 30 who explicitly supported Lashkar-e-Taiba, a jihadist group that fights on the Kashmir issue and is associated with al-Qaeda. They also explicitly supported armed jihad more broadly, saying that they would be willing to carry out an act of armed jihad and endorsing violence against the West. These participants were thus far more radicalised than those in our previous study.

As in the previous study, our participants evaluated their willingness to fight and die for various sacred and non-sacred values while in the scanner. This time, however, after they had made their evaluations, they were presented with their own responses and the average responses of Pakistanis from the broader community in Barcelona. Unbeknown to them, these responses were invented. They showed that half the time the average willingness to fight and die of the broader community was the same as that of the participants and half the time it was lower (we also wanted to include a third condition where the community responses were higher but this was not possible since the participants gave responses that were already at the extreme end of the spectrum). The Lashkar-e-Taiba supporters then left the scanner and re-evaluated their willingness to fight and die for all values.

We found that parts of the brain associated with deliberation and self-control (such as the dorsolateral prefrontal cortex) went “offline” when participants evaluated their willingness to fight and die for their sacred values. However, when they were presented with the information that their peers (other local Pakistanis) had a lower willingness to fight and die than them, this caused that same area to come back “online”. Not only that, when the supporters re-evaluated their willingness to fight and die, they reduced it to conform with their peers’ responses. Furthermore, the degree of reactivation of self-control regions of the brain predicted the extent of their conformity with their peers’ responses, indicating a link between the activation of those brain areas and the extent of their behavioural change. As such, the Lashkar-e-Taiba supporters did not change their sacred values but they did change the level of violence they were willing to engage in to defend those values once they realised it was out of step with their peer group. This provides evidence of one way – bringing the attitudes of the broader peer group to an extremist’s attention – to move a devoted actor off the path of violence.

Social, Behavioural and Brain Sciences Informing Policy Together

Both of these studies were inspired by decades of research from the social and behavioural sciences that highlight the importance of social exclusion and social norms (that is, what people suspect their peer group thinks are acceptable beliefs or behaviours). Qualitative research on violent extremism in SyriaSomalia and Nigeria has shown the importance of social exclusion as a motivating factor for why people join jihadist groups. Longitudinal survey research in the United States has shown that when marginalised Muslims face discrimination they increase their support for radical groups. Similarly, the role of social norms in reducing violent conflict has been demonstrated in post-conflict reconciliation environments. Large-scale randomised control trial studies in Rwanda and the DRC demonstrated that social norms embedded in radio soap opera programmes increased willingness for reconciliation and cooperation by changing perceptions of social norms while having no effect on personal beliefs. The neuro-imaging research simply augments these findings by offering yet another source of data.

While these studies may be the first conducted on radicalised populations, there are exciting findings emerging from adjacent fields, such as neuro-criminology. Research has shown that youth who have adverse childhood experiences grow up with an increased likelihood for delinquency and criminal behaviour, especially once they reach adolescence and early adulthood. Given the well-established links between crime and terrorism, these findings could bear important policy implications for violent extremism as well.

An obvious policy suggestion would be to try to reduce such adverse experiences in children’s lives. But what could one suggest if a child has already experienced these adversities but has not yet reached adolescence? There seems to be a window of opportunity to intervene. However, if we do not understand which psycho-neural mechanisms create the increased vulnerability to crime and extremism, any intervention will be little more than a shot in the dark. Luckily, there is some ongoing research that shows that adverse childhood experiences negatively impact sympathetic nervous system reactivity but that high-quality friendships by the age of twelve can buffer against some of these outcomes. If these results can be replicated, they will add to the research demonstrating the importance of peers, in terms of both social exclusion and social norms, in either increasing or decreasing an individual’s propensity for political violence.

This kind of research is especially prescient in such countries as Syria, Iraq and South Sudan, where there are potentially tens of thousands of children who are in this window of opportunity after having survived early childhood years amid armed conflict. Discovering and offering the right kinds of interventions for these children is a humanitarian concern, while failing to do so could lead to security issues in the future if armed groups are able to prey on unhealed trauma for recruitment purposes.

Neuroscience need not be seen as a pariah invading the domain of social and behavioural sciences, nor should it be seen as a prophet descending from on high to answer all our security-related questions. Instead, it is an ally for all empirical work that seeks to understand the factors that move people closer to or further from violence. Its findings can help to aid theoretical developments and provoke practical policy suggestions.

This blog was originally published on the International Centre for the Study of Radicalisation’s website.