Social Cognitive and Affective Neuroscience, 2019, 569–577 doi: 10.1093/scan/nsz034 Advance Access Publication Date: 6 May 2019 Original article Ventromedial and dorsolateral prefrontal interactions underlie will to fight and die for a cause Clara Pretus,1,2,10 Nafees Hamid,1,3 Hammad Sheikh,1,4 Ángel Gómez,1,5 Jeremy Ginges,1,4 Adolf Tobeña,1,2 Richard Davis,1,6,7 Oscar Vilarroya,1,2 and Scott Atran1,7,8,9 1 Artis International, Scottsdale, AZ 85254, USA, 2 Departament de Psiquiatria i Medicina Legal, Universitat Autònoma de Barcelona, Cerdanyola del Vallès 08193, Spain, 3 Department of Security and Crime Science, University College London, London WC1H 9EZ, England, 4 Department of Psychology, New School for Social Research, New York, NY 10011, USA, 5 Departamento de Psicología Social y de las Organizaciones, Universidad Nacional de Educación a Distancia, Madrid 28040, Spain, 6 School of Politics and Global Studies, Arizona State University, Tempe, AZ 85287, USA, 7 The Changing Character of War Centre, Pembroke College, University of Oxford, Oxford OX1 1DW, England, 8 Centre National de la Recherche Scientifique, Institut Jean Nicod–Ecole Normale Supérieure, Paris 75005, France, 9 Gerald Ford School of Public Policy and Institute for Social Research, University of Michigan, Ann Arbor 48109, MI USA, and 10 Fundació IMIM (Institut Municipal d’Investigacions Mèdiques), 08003 Barcelona, Spain Correspondence should be addressed to Clara Pretus, Departamento de Psiquiatria i Medicina Legal, Facultat de Medicina, Campus de Bellaterra, 08193, Cerdanyola del Vallès, Barcelona, Spain. E-mail: clara.pretus@gmail.com. Abstract Willingness to fight and die (WFD) has been developed as a measure to capture willingness to incur costly sacrifices for the sake of a greater cause in the context of entrenched conf lict. WFD measures have been repeatedly used in field studies, including studies on the battlefield, although their neurofunctional correlates remain unexplored. Our aim was to identify the neural underpinnings of WFD, focusing on neural activity and interconnectivity of brain areas previously associated with value-based decision-making, such as the ventromedial prefrontal cortex (vmPFC) and the dorsolateral prefrontal cortex (dlPFC). A sample of Pakistani participants supporting the Kashmiri cause was selected and invited to participate in an functional magnetic resonance (fMRI) paradigm where they were asked to convey their WFD for a series of values related to Islam and current politics. As predicted, higher compared to lower WFD was associated with increased ventromedial prefrontal activity and decreased dorsolateral activity, as well as lower connectivity between the vmPFC and the dlPFC. Our findings suggest that WFD more prominently relies on brain areas typically associated with subjective value (vmPFC) rather than integration of material costs (dlPFC) during decision-making, supporting the notion that decisions on costly sacrifices may not be mediated by cost-benefit computation. Key words: costly sacrifices; will to fight and die; sacred values; fMRI; functional connectivity Introduction across a number of contexts, such as the Israeli–Palestinian In previous studies, our research group has studied beliefs conflict (Sheikh et al., 2013), the US–Iranian nuclear conflict and values embedded within protracted political conflict (Dehghani et al., 2009), the Indian–Pakistani conflict over Received: 7 November 2018; Revised: 24 March 2019; Accepted: 29 April 2019 © The Author(s) 2019. Published by Oxford University Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com 569 570 Social Cognitive and Affective Neuroscience, 2019, Vol. 14, No. 6 Kashmir (Sachdeva and Medin, 2009) and the frontline battle compared to low WFD to be positively correlated with brain against Islamic State (ISIS) in Iraq (Gómez et al., 2017). Across activity that is typically associated with subjective value during these samples, their report high levels of commitment to their decision-making (vmPFC). Because the personal drive to fight in-group and the values, often showing willingness to personally and die for a cause often runs independently of risks and out- fight and die to defend them. Thus, the need emerged to develop comes for the self (Sheikh et al., 2016), we also anticipated lower a suitable measure to assess motivation for incurring extreme integration of costs, hence, reduced activity in the dlPFC, during personal costly sacrifices including risking one’s life and the high vs low WFD decisions. For the same reason, we expected lives of others to defend highly cherished beliefs. To this end, functional connectivity between the dlPFC and the vmPFC to be willingness to fight and die (WFD) was developed as a measure weak or even negative in the high vs low WFD condition. of extreme commitment in field studies of value-based conflicts, whether involving active supporters (Swann et al., 2009; Gómez Methods et al., 2011; Atran et al., 2014a; Atran et al., 2014b) or frontline combatants (Gómez et al., 2017). Participants Behavioral field studies show that decisions over willingness The study was approved by the Institutional Review Board Ethics to engage in costly sacrifices for the sake of a greater cause Committee according to the Declaration of Helsinki guidelines escape instrumental reasoning and cost-benefit computation and informed consent was obtained from all participants before (Ginges et al., 2011). For example, willingness to partake in polit- taking part in the study. Data protection was a priority in this ical violence compared to non-violence was mainly predicted study and complete anonymity was guaranteed. by perceived righteousness, with little contribution of perceived Participants were selected by means of field interviews and effectiveness, whereas support for military compared to diplo- surveys with a sample of 146 male respondents of Pakistani ori- matic solutions to a conflict was insensitive to quantity in terms gin living in migrant marginalized neighborhoods of Barcelona of number of saved lives and number of deterred enemy attacks (Spain); the average age was 30.82 years old (range 18 to 62). All in the future (Ginges and Atran, 2011). respondents were Muslim, and most self-identified as Sunni. In Value-based choices are generally thought to be modulated line with the recruitment criteria, all participants in the selected by interactions between the dorsolateral prefrontal cortex sample expressed (i) support for a jihadist group that fights for (dlPFC) and the ventromedial prefrontal cortex (vmPFC) usually the Pakistani reclamation of Kashmir (ii) agreement with armed favoring adaptive behavior (Hare et al., 2009; Basten et al., 2010; jihad (iii) agreement that Muslims must unite against the West Rudorf and Hare, 2014). Whereas the vmPFC has been proposed by all means necessary and (iv) willingness to personally engage as a global value comparator that computes subjective value or facilitate violence in the name of armed jihad (to engage in (Basten et al., 2010; Camille et al., 2011), the dlPFC is thought violent protest, to financial support a non-state militant group, to modulate value encoding during decisions that integrate to join a non-state militant group or to fight and die on their costs (Hare et al., 2009) or reweight stimulus attributes (Rudorf own in support of armed jihad). From those n = 45 respondents and Hare, 2014). However, the interplay between the dlPFC who met all three criteria in the field survey, n = 30 agreed to and the vmPFC during value-based decisions has not yet been participate in the fMRI study. investigated in the context of WFD. Although WFD should The final fMRI study sample consisted of male Muslim par- broadly recruit brain networks associated with value-based ticipants from Pakistani origin living in and around Barcelona. choice, such as the vmPFC and dlPFC (Plassmann et al., 2007; The average age was 30.10 years old (s.d. = 5.37, range from 18 Hutcherson et al., 2012), decisions involving high compared to to 39 years old): 51.7% of them were married, 82.7% finished low WFD might be expected to show substantial differences in secondary school and 10.3% held a bachelor’s degree; 72.4% the extent to which brain regions associated with cost-benefit reported a well below average income; and 72.4% stated that calculation are recruited. religion was the most important thing in their lives. All but one Accordingly, the goal of the present study was 2-fold. First, agreed that ‘India should have no right to ownership of Kashmir’ we sought to identify the neural correlates of WFD by com- and all of them reported a favorable or somewhat favorable paring values receiving high vs low WFD ratings, especially opinion of Lashkar-e-Taiba (LeT or ‘army of the pure’), one of focusing on activity in usual decision-making neural hubs such the largest militant Islamist groups in Pakistan functioning since as the dlPFC and vmPFC. Second, we endeavored to establish 1993 and declared a terrorist group by the US (2002) followed a functional connectivity profile between these brain regions, by the UN (2005). The organization fights for the liberation of respectively associated with integration of costs during decision- Kashmir from Indian control and the unification of all Muslim making (dlPFC) and subjective value computation (vmPFC), dur- majority regions beyond Pakistan, pointing at the US, Israel ing proceeding of WFD. For this purpose, we recruited a sample of and India as existential enemies of Islam, as reported by the male participants of Pakistani origin living in Barcelona (Spain) SATP (South Asia Terrorism Portal, www.satp.org). LeT has been who expressly supported the cause of Kashmiri resistance to attributed several violent attacks including the 2008 Mumbai Indian rule, and then scanned them while they expressed WFD bombings, which caused 200 deaths and 300 injured civilians, for a series of values related to Islam and current politics. We and the Indian parliament attacks in 2001 (see Box 1 for more then analyzed neural activity associated with high and low WFD, details on the Kashmir conflict). and compared functional connectivity between the dlPFC and the vmPFC in these two conditions using the CONN functional connectivity toolbox (The Gabrieli Lab, McGovern Institute for Box 1 The Kashmir conflict started in 1947 with India’s Brain Research). This toolbox allows quantifying the co-variance independence and its partition from Pakistan. Although among previously selected neural regions, or between previously it began as a territorial dispute it has evolved into a selected neural regions and the rest of the brain, in a given clash between Hindu and Muslim religious identities espe- experimental condition. cially salient for the Muslim community (Sachdeva and Given that WFD for a value is a measure that reflects dis- Medin, 2009). The first war between India and Pakistan over position to incur extreme costly sacrifices, we predicted high C. Pretus et al. 571 five pairs of circles, one representing the self (a small circle) Kashmir in 1947 caused mass killings of all ethnic groups and another representing the group (a big circle), with varying and hundreds of thousands of refugees. In 1948 the UN degrees of overlap between the circles. From the five options, Security Council imposed a ceasefire, forcing Pakistan only the option representing the small circle fully inside the to withdraw its troops, and promised a plebiscite for big circle denotes fusion. We added an additional response Kashmiris to democratically vote for their independence. option to the original scale showing no contact at all between Neither Pakistan obeyed nor did the plebiscite take place, the two circles owing to the reluctance of some respondents creating a climate of escalating violence leading to the to accept any contact between the circles in previous field Sino–Indian war in 1962 and the Indo–Pakistani war in studies (Gómez et al., 2017). These were intended to measure 1971. The Indian military occupation lead to the formation the extent to which respondents felt ‘viscerally connected’ of opposing Muslim militant groups, culminating in the to a reference group such as nation or religious community Mujahedeen insurgency in 1989, which has caused 70 000 (Gómez et al., 2017). deaths and 8000 missings to date. The most recent cease- fire resolution between Pakistan and India was signed in 2003, although there have been several violent attacks from fMRI paradigm both sides ever since. Currently, 43% of the territory is The rapid event-related fMRI paradigm was designed using controlled by India, 37% by Pakistan and 20% by China. MATLAB 2012a (The MathWorks, Inc., Natick, Massachusetts, The general Pakistani view defends that Kashmir should USA) with Psychtoolbox extensions (Kleiner et al., 2007). During be independent or annexed to Pakistan, according to its brain scanning, participants rated their WFD for each value (one Muslim majority and responding to the Kashmiri uprising. value per trial) by means of a 7-point Likert scale ranging from 1 (not willing) to 7 (extremely willing). Values were presented in Urdu (see Figure S1). Linguistic variations of each value produced 80 different trials (40 sacred value trials and 40 Procedure non-sacred value trials) with controlled length and sentence Participants were invited to the fMRI facilities where they structure in order to increase the number of trials within the completed a pre-scan survey and an fMRI task described fMRI paradigm without wording repetitions. A post hoc analysis below. The pre-scan survey was used to determine which comparing stimulus length in Urdu showed no differences values were perceived as sacred (non-negotiable) and non- in stimulus length neither between sacred and non-sacred sacred (mundane values) by each participant in order to ensure value trials (sacred values: M = 12.05 words, s.d. = ±.28; non- sufficient variability in the WFD measure. A list of 25 candidate sacred values: M = 11.97 words; s.d. = ±.6, t(28) = .598, P = .555) values was presented to participants, which was designed based nor between the conditions of interest, that is, high and low on previous ethnographic fieldwork and included topics relevant WFD (high WFD: M = 12.08 words, s.d. = ±.36; low WFD: M = 12.04 to the sample population: ‘Western military forces should be words, s.d. = ±.76, t(28) = .204, P = .840). Stimuli were presented expelled from Muslim lands’, ‘Strict sharia should be applied in randomly with jittered inter-trial intervals in two runs. Inter- all Muslim countries’, ‘Armed jihad should be waged against the trial interval durations varied randomly from 2.5 s up to 12.5 s enemies of Muslims’, ‘India should have no right to ownership in 2.5 s steps. Participants were instructed to read the value of Kashmir’, ‘Current Muslim countries should be unified in a and, once they knew their response, convey their WFD making single Caliphate’, among others (see full list in Table S1). In line use of the 7-point Likert scale located below the value using with previous work on sacred values (Baron and Spranca, 1997; left/right buttons. The participant’s response was recorded based Tetlock, 2003; Berns et al., 2012), a value was considered sacred on their button presses by means of Psychtoolbox functions on if: (i) participants refused any material incentive to give it up, Matlab. Pilot testing with non-selected candidates from the same such as better economic conditions for their own community, population allowed establishing a response time of 10 s (reading that is, they responded ‘No’ instead of ‘Yes’ or ‘Maybe’ to the + responding), which allowed all participants to respond to question ‘Would you be willing to give up this value if adopting most trials. The values and the 7-point Likert scale were always the opposite position entailed better economic conditions for presented in the same location of the screen and the cursor’s your community?’, and (ii) their stance was immune to social starting point was always at 4 points, the center of the scale (if influence, that is, they responded ‘No’ instead of ‘Yes’ or their response was actually a 4, they were instructed to go either ‘Maybe’ to the question ‘If there was a democratic consensus left or right and then back to 4, otherwise the trial counted over the opposite position, would you find it acceptable?’ as a null). The value remained on screen until the 10 s were (Fiske and Tetlock, 1997; Baron and Leshner, 2000; Ginges et al., over. Keeping stimuli in place facilitated reading and reduced 2007; Berns et al., 2012; Sheikh et al., 2013). Participants had to confusion. Before starting the fMRI paradigms, participants respond ‘No’ to both questions in order for the value to be practiced the task in a computer until fully comprehending the considered sacred. Next, participants ranked their sacred and exercise and mastering control of the response buttons. non-sacred values by importance and the top 6 sacred values, as well as 6 randomly chosen sacred values were selected for the fMRI paradigm. There was a considerable amount MRI acquisition of overlapping between each participants’ sacred value and Images were acquired in a Siemens 3 T scanner. T1-weighted non-sacred value sets, with the most frequently employed images were obtained using a fast spoiled gradient-echo (FSPGR) sacred values being those including religious content (see sequence (TR: 11.6 ms, TE: 4.8 ms, FA: 12, matrix size: 280 × 280, Table S1). Measures of identity fusion with seven different 150 slices, slice thickness: 1.00 mm). An EPI-T2∗ sequence groups (Swann et al., 2009), including ‘Islam’, ‘Muslim Ummah’, allowed obtaining the functional volumes, each comprising forty ‘Pakistan’, ‘Spain’, ‘Borderless Muslim Caliphate’, ‘Federated 3.4 mm thick slices (TR 2500 ms, TE: 27 ms, FA: 90, matrix size: Muslim Caliphate’ and ‘Close Friends’, were also administered 64 × 64, 40 slices, slice thickness: 3.4 mm). Head motion was in the pre-scan survey. The identity fusion measure includes tracked by means of center of mass measurements during image 572 Social Cognitive and Affective Neuroscience, 2019, Vol. 14, No. 6 acquisition. None of the participants showed head movement variable in this analysis. Post hoc analyses included parameter above voxel size acquisition after a post hoc evaluation of the six estimate extraction of vmPFC and left and right dlPFC activity head movement parameters. in the high WFD vs baseline and the low WFD vs baseline Statistical Parametric Mapping (SPM12) (Welcome Department contrast using Marsbar in order to illustrate the amount of region of Imaging Neuroscience, London, UK) and the Analysis of of interest (ROI) activity in each condition. Reported results Functional Neuroimaging software were employed for the were corrected for multiple comparisons using family-wise error functional MRI data analysis. Functional images were despiked (FWE) correction at cluster level, single voxel P < 0.001. Analysis of Functional NeuroImages (AFNI), corrected for motion-related artifacts (SPM12), normalized to MNI standard space (SPM12), smoothed with a 8 mm full-width-at-half- Effective connectivity analysis maximum Gaussian kernel (SPM12) and detrended (AFNI). The functional connectivity analysis was conducted by means of the connectivity toolbox CONN on SPM12 (Whitfield-Gabrieli Behavioral analysis and Nieto-Castanon, 2012). To test the interplay between brain regions associated with executive control (dlPFC) and subjective The behavioral analysis included a paired sample t-test compar- value computation (vmPFC) during high and low WFD, a series ing WFD ratings in the high WFD condition and the low WFD of anatomical ROIs were defined using Automated Anatomical condition. The effect of value sacredness on WFD ratings was Labeling (aal) labels (Neurofunctional Imaging Group, Université computed by means of a repeated measures analysis of variance de Bordeaux). These ROIs included the left dlPFC (left middle (ANOVA) assessing value sacredness as a within-subjects factor. frontal gyrus), the right dlPFC (right middle frontal gyrus) and Percentages of fused participants (6 out of 6 points) were cal- the vmPFC (bilateral medial orbitofrontal gyrus). For each partic- culated for each identity fusion scale and correlations between ipant, a generalized Psycho-Physiological Interaction (gPPI) anal- identity fusion and WFD ratings were conducted. ysis was conducted. The gPPI analysis tests the task-modulated effective connectivity between pairs of a previously defined set Neuroimaging analysis of ROIs (here: right dlPFC, left dlPFC and vmPFC) by means of a multiple regression model incorporating task effects, the Image processing was conducted using the SPM12 function ROIs timeseries and an interaction term (PPI term) between package (Wellcome Trust, University College London, UK) on both parts. The effects of the high and low WFD conditions on MATLAB. Trials were split in high vs low WFD as a function of effective connectivity between the bilateral dlPFC and the vmPFC each participant’s average. The first-level general linear model were then computed and compared. Group-level gPPI results (GLM) included two regressors for trials where participants were corrected for multiple comparisons at seed level (P < 0.05 conveyed either high (above each participant’s mean) or low FWE). (below each participant’s mean) WFD ratings. The average number of trials was 47.2 (s.d. = ±8.82) in the high WFD condition, and 32.8 (s.d. = ±8.82) in the low WFD condition. The duration of Results the events spanned from stimulus onset up to the participant’s first button press, and thus, it varied from trial to trial. Each The average WFD rating in the high WFD condition was 6.67 (s.d. condition was parametrically modulated by a binary regressor ±0.48), whereas the average WFD rating in the low WFD condi- with ones and zeros, including whether the value at stake was tion was 3.94 (s.d. ± 1.02). The average response time was 5.93 s sacred (1) or not (0). Of note, the high and low WFD conditions did (s.d. = ±1.03), and no differences in response time were detected not always correspond to responses to sacred and non-sacred between conditions (High WFD condition: M = 5.02, s.d. = ±1.22; values, respectively. That is, the high WFD condition included, Low WFD condition: M = 5.04, s.d. = ±1.38; t(28) = −.089, P = .930). at average, 77.11% trials with sacred values (s.d. = 13.96%) and In addition, response time did not correlate with WFD ratings, the low WFD condition included, at average, 12.81% trials with neither when analyzing all trials together (r = −.032, P = .868) nor sacred values (s.d. = 13.94%). Because sacred values entail higher when evaluating each condition separately (high WFD condition: levels of attitude strength, familiarity, salience and emotional r = .070, P = .718; low WFD condition: r = .042, P = .828). Indeed, intensity than non-sacred values (Pretus et al., 2018; Hamid et al., value sacredness as a within-subjects factor had a significant 2019), the inclusion of a value sacredness parametric regressor effect on WFD (F(1) = 168.612, P < .001). was crucial to account for these confounding effects on the Seventy-five percent of the sample was fused with Islam, measures of interest (WFD). Missing trials (no button response 72.4% with the Muslim Ummah, 93.1% with Pakistan, 31% with throughout the trial), which were, at average, 3.62 trials per Spain, 21% with a Borderless Muslim Caliphate, 24% with a Fed- participant (s.d. = ±5.44) were not modeled in the GLM, and erated Muslim Caliphate and 79.3% with Close Friends. Identity thus, they were processed as part of the implicit baseline. In fusion with Pakistan was the only identity fusion measure that turn, in order to account for the confounding effects of motor correlated with WFD (r = 0.388, P < 0.038), although this result did preparation and response, we introduced an hrf-convolved not survive Bonferroni correction. button press regressor. Six non-convolved head movement fMRI signal contrasts between high vs low WFD appear in regressors were also included. Table 1. The high compared to the low WFD condition was Group-level effects of the high vs low WFD contrast were associated with greater activity in a cluster encompassing evaluated by means of a t-test on individual level contrasts. In the anterior cingulate cortex and the left middle orbital addition, we ran a second-level regression with identity fusion gyrus (T = 4.49, k = 446, P = 0.013 FWEc) and lower activity in with Islam and the Muslim Ummah as a predictor of neural the right inferior parietal lobule (T = 5.49, k = 1690, P < 0.001 activity in the high vs low WFD contrast as well as in high FWEc), right middle frontal gyrus (T = 5.47, k = 424, P = 0.016 and low vs baseline contrast, respectively. In order to be able FWEc), left superior medial frontal gyrus (T = 5.37, k = 735, to capture more subtle differences in neural activity associated P = 0.001 FWEc), left inferior parietal lobule (T = 5.33, k = 1800, with identity fusion, identity fusion was used as a continuous P < 0.001 FWEc) and a cluster including the left inferior frontal C. Pretus et al. 573 Table 1. Results of the high vs low WFD contrast thresholded at T = 3.4, P < 0.05 FWE cluster-level corrected, single level P < 0.001 MNI coordinates Region label k T(28) x y z p-FWEc High > Low WFD L ACC 446 4.49 −4 38 0 0.013 Location not in atlas 446 4.07 26 38 2 0.013 L Mid orbital gyrus 446 3.52 −2 62 −2 0.013 Low > high WFD R Supramarginal gyrus 1690 −5.49 56 −32 54 <0.001 R Angular gyrus 1690 −3.88 40 −72 48 <0.001 R Middle frontal gyrus 424 −5.47 48 36 32 0.016 L Superior medial gyrus 735 −5.37 0 24 46 0.001 L Inferior parietal lobule 1800 −5.33 −54 −40 54 <0.001 L Inferior parietal lobule 1800 −5.05 −36 −44 46 <0.001 L Superior parietal lobule 1800 −4.54 −26 −68 62 <0.001 L IFG (pars triangularis) 1230 −5.11 −40 20 6 <0.001 L IFG (pars triangularis) 1230 −4.99 −52 14 32 <0.001 L Middle frontal gyrus 1230 −3.50 −44 34 32 <0.001 gyrus (pars triangularis) and left middle frontal gyrus (T = 5.11, cost-benefit computation, high compared to low WFD negatively k = 1230, P < 0.001 FWEc; see Figure 1A and B). Post hoc parameter correlated with brain activity associated with integration of costs estimates analyses corroborated the increased vmPFC activity and stimulus reweighting, that is, the dlPFC (Hare et al., 2009; (t(28) = 3.25, P = 0.003) and decreased left PFC (t(28) = −2.19, Rudorf and Hare, 2014). In addition, the effective connectivity P = 0.037) and right dlPFC (t(28) = −3.00, P = 0.006) activity in the analysis revealed a stronger negative correlation between the high WFD vs baseline contrast compared to the low WFD vs vmPFC as a seed region and the bilateral dlPFC in the high vs baseline contrast, although the left dPFC comparison did not low WFD condition. survive Bonferroni correction (see Figure 1B). Differences in WFD Other neuroimaging studies on decision-making report scores in the high vs low WFD conditions correlated with neural interactions between the vmPFC and the dlPFC during value- activity differences in the left dlPFC (r = −0.578, P = 0.001) and based choices. For example, Baumgartner et al. (2011) observed right dlPFC (r = −0.456, P = 0.013), but not the vmPFC, between increased dlPFC activity and higher functional connectivity conditions after Bonferroni correction (see Figure 1C). between the dlPFC and the vmPFC during decisions where Study participants were predominantly fused with Islam and fairness and self-interest were in conflict (i.e. in participants the Muslim Ummah; however, the available variability was neg- who more frequently made fair decisions vs participants atively associated with left middle frontal gryus activity in the who made more selfish decisions, but no between-group high WFD vs baseline contrast (T = 5.01, k = 489, P = 0.024 FWEc) differences in non-conflicting decisions). Similarly, Hare et al., and in the high vs low WFD contrast (T = 4.38, k = 71, P = 0.045 2009 found higher dlPFC activity and increased dlPFC–vmPFC FWEc after small volume correction with the left dlPFC ROI, see connectivity during decisions about food consumption in dieting Figure 2). However, identity fusion with Islam and the Muslim ‘self-controllers’ (participants evaluating both taste and health Ummah did not significantly correlate with average WFD scores for each food item) vs dieting ‘non-self-controllers’ (evaluating (r = 0.141, P = 0.467) nor with WFD scores in the high (r = 0.058, taste only); and there was a correlation between vmPFC activity P = 0.766) or low (r = 0.066, P = 0.735) WFD condition, probably due and food value regardless of self-control. to a limited variability of identity fusion in this sample. Nevertheless, none of these prior studies investigated The gPPI analysis revealed a negative effective connectivity the relationship between these brain areas in regard to between the vmPFC as a seed region and the bilateral dlPFC decisions involving costs in human lives. Here, we found (F(2)(27) = 2.98, Intensity = 4.25, P = 0.01 FWE seed-level corrected) that decisions over WFD for a cause were modulated by when comparing the high vs low WFD conditions (see Figure 3). interactions between the vmPFC and the dlPFC. Particularly, Results of the reverse contrast (low > high WFD) did not survive the vmPFC was more active, and the dlPFC, together with multiple comparisons correction. other fronto-parietal areas, such as the left inferior frontal gyrus and the bilateral parietal lobe, was less active during decisions involving high WFD for a cause. Several studies point at the vmPFC as an integration hub that reflects the Discussion subjective value of a given choice ‘all things considered’ The present study aimed to identify the neural underpinnings of (Chib et al., 2009; Peters and Büchel, 2010; Bartra et al., 2013; WFD for the sake of values related to Islam in a sample of Pak- Shenhav and Greene, 2014). Moreover, the dlPFC has been istani participants supporting the cause of Kashmiri resistance associated with a myriad of functions related to executive to Indian rule. As anticipated, decisions involving high compared control, such as stimulus reweighting (Rudorf and Hare, 2014) to low WFD (with respect to each participants’ average) corre- and integration of costs (Hare et al., 2009). More generally, the lated with higher ventromedial prefrontal activity (vmPFC), a fronto-parietal network, including areas found to be less active brain region typically associated with subjective value computa- in the high vs low WFD conditions (inferior frontal gyrus and tion during decision-making (Plassmann et al., 2007; Bartra et al., the parietal lobules), has been associated with cognitive control 2013). Moreover, consistent with behavioral field studies indicat- enabling rapid and flexible goal-oriented behavior (Marek and ing that decisions over costly sacrifices run independently from Dosenbach, 2018). From this perspective, our results suggest 574 Social Cognitive and Affective Neuroscience, 2019, Vol. 14, No. 6 Fig. 1. Results of the high vs low WFD contrast. (A) The high vs low WFD condition yielded higher activity in a cluster including the anterior cingulate cortex (ACC) and the vmPFC (in red-yellow) and lower activity in the superior medial frontal gyrus, the right middle frontal gyrus, Left inferior frontal gryus (pars triangularis) and bilateral inferior parietal lobule (in blue-green). Results thresholded at T = 3.4. P < 0.05 FWEc. single level P < 0.001. (B) Parameter estimates of vmPFC activity were higher in the high WFD vs baseline condition compared to the low WFD vs baseline condition (t(28) = 3.25. P = 0.003), while those of the bilateral dlPFC were lower (left dlPFC: t(28) = 2.19. P = 0.037; right dlPFC: t(28) = 3.00. P = 0.006) in the same contrast. (C) Between-conditions difference in WFD ratings correlated with between-conditions left dlPFC (r = −0.578, P = 0.001) and right dlPFC (r = −0.456, P = 0.013), but not with vmPFC activity difference, after Bonferroni correction for three tests (one per ROI). Fig. 2. Correlations between neural activity and identity fusion measures. (A) Surface projection of the left middle frontal gryus activity predicted by fusion with Islam and the Muslim Ummah in the high WFD vs baseline contrast (T = 5.01, k = 489, P = 0.024 FWEc) and in the high vs low WFD contrast (T = 4.38, k = 71, P = 0.045 FWEc after small volume correction with the left dlPFC ROI). (B) Scatterplot of the correlation between the fusion score and left middle frontal gryus parameter estimates found in the high WFD vs baseline contrast (r = −0.659, P < 0.001) and the high vs low WFD contrast (r = −.627, P < 0.001). (C) Results table of the second-level GLM using identity fusion with Islam and the Muslim Ummah as predictor of brain activity in the high and low WFD vs baseline contrasts, respectively, and the high WFD vs low WFD contrast. that high (vs low) WFD choices could involve higher subjective dlPFC). In addition, high compared to low WFD was associated value, with little contribution of brain regions associated with negative effective connectivity between the vmPFC as with integration of costs and cognitive control (including the a seed region and the bilateral dlPFC. This finding suggests C. Pretus et al. 575 Fig. 3. Effective connectivity analysis results. (A) Parameter estimates of the high WFD effects (dark red) and the low WFD effects (light red) on the effective connectivity between each pair of ROIs including the left and right dlPFC and the vmPFC (‘[seed region]–[target region]’). (B) 3D display of the effective connectivity differences between the high and low WFD conditions after FWE seed-level correction (left lateral and superior view). (C) Effective connectivity results table comparing high > low WFD including a negative correlation between the vmPFC as a seed region and the bilateral dlPFC; no significant results were found in the reverse contrast (low > high WFD). that a greater vmPFC response contributes to bilateral dlPFC violence (military action) compared to non-violence (diplomacy) downregulation during decisions involving high WFD for a was mainly predicted by perceived righteousness, with little con- cause. In this vein, future research should clarify whether tribution of perceived effectiveness, whereas support for military stimulating dlPFC activity effectively decreases WFD ratings compared to diplomatic solutions to a conflict was insensitive for causes that would otherwise be associated with high WFD to quantity in terms of number of saved lives and number of responses. deterred future attacks by the enemy (Ginges and Atran, 2011). Finally, most participants were fused with Pakistan, Islam Participants were ready to support a military intervention to and the Muslim Ummah, in line with studies showing identity resolve a hypothetical international conflict if it meant saving fusion in frontline fighters, who establish family-like bonds the life of a single hostage or deterring one future attack. By with fellow combatants (Whitehouse et al., 2014; Gómez et al., contrast, diplomatic solutions were favored only if they involved 2017). Available variability revealed a positive correlation saving more than 100 hostages or 60 future attacks (Ginges and between identity fusion with Islam and the Mulsim Ummah and Atran, 2011). decreased dlPFC recruitment during the high WFD condition The present study has several limitations. On one hand, (both compared to baseline and compared to the low WFD values in the high and low WFD conditions differed in a number condition), although this did not entail higher WFD ratings. of ways, including emotional intensity, familiarity and salience. Identity fusion is associated with commitment and costly This owes to the fact that sacred values (higher emotional inten- sacrifices in defense of in-group values (Swann et al., 2014). sity, familiarity and salience) were more often than not included Identity fusion is one of the components of the ‘devoted actors in the high WFD condition, whereas the opposite was true for model’, which characterizes individuals whose personal identity non-sacred values. This confound was addressed by including a is merged or ‘fused’ with that of their social group and to the binary parametric regressor in the high and low conditions indi- group’s most cherished (sacred) values (Atran et al., 2014a; Atran, cating whether the value at stake was sacred or not. However, 2016; Sheikh et al., 2016; Gómez et al., 2017). For similar levels of we understand that if a value is worth fighting and dying for, it in-group commitment (similar WFD ratings), fused participants will almost certainly entail higher levels of emotional intensity showed a lower reliance on brain areas typically associated with and salience. Hence, we tend to think that such qualities are integration of costs during decisions involving costly sacrifices intrinsic (rather than a confound) to high levels of WFD. On the (left dlPFC). This finding suggests that the effect of identity other hand, it would have been interesting to compare WFD and fusion on dlPFC activity alone cannot account for the observed willingness to pay for goods in the same individuals in order to high WFD making use of the present experimental design. evaluate the degree of overlap between the functional clusters Our results are consistent with behavioral studies showing underlying value-based choice in the social cause vs material that decisions over willingness to engage in costly sacrifices goods condition. Further research is needed to specifically test for the sake of a greater cause escape instrumental reasoning whether the pattern of dlPFC–vmPFC interactions is consistent and cost-benefit computation (Ginges and Atran, 2011). In those across social and material values, or whether discrepancies prior studies, decisions over willingness to resort to political modulated by individual traits, such as identity fusion, exist. 576 Social Cognitive and Affective Neuroscience, 2019, Vol. 14, No. 6 Finally, our study is limited by the fact that it focuses on a popu- Berns, G.S., Bell, E., Capra, C.M., et al. (2012). The price of your lation involved in a particular conflict. Future research should soul: neural evidence for the non-utilitarian representation of compare behavioral and neuronal processes associated with sacred values. Philosophical Transactions of the Royal Society B: WFD to fight and die across communities involved in different Biological Sciences, 367, 754–62. world conflicts. Camille, N., Griffiths, C.A., Vo, K., et al. (2011). Ventromedial In sum, our findings support the notion that WFD relies frontal lobe damage disrupts value maximization in humans. on brain activity that is generally associated with subjective The Journal of Neuroscience: The Official Journal of the Society for value computation (vmPFC). Moreover, in line with behav- Neuroscience, 31, 7527–32. ioral data showing that decisions on costly sacrifices run Chib, V.S., Rangel, A., Shimojo, S., et al. (2009). Evidence for a com- independently from cost-benefit ponderation (Ginges et al., mon representation of decision values for dissimilar goods in 2011), high compared to low WFD was characterized by human ventromedial prefrontal cortex. Journal of Neuroscience, decreased recruitment of brain regions previously associated 29 (39), 12315–20. with integration of costs during decision-making, such as the Dehghani, M., Iliev, R., Atran, S., et al. (2009). Emerging sacred dlPFC. Accordingly, our data also reveal a negative effective values: the Iranian nuclear program. Judgment and Decision connectivity between the vmPFC and the bilateral dlPFC Making, 4, 990–3. associated with high compared to low WFD. By providing Fiske, A.P., Tetlock, P.E. (1997). Taboo trade-offs: reactions to a neurobiological perspective via fMRI measures and brain transactions that transgress the spheres of justice. Political functional connectivity, these findings are potentially relevant to Psychology, 18, 255–98. identifying later stages of radicalization that involve WFD for a Ginges, J., Atran, S. (2011). War as a moral imperative (not just cause. practical politics by other means). Proceedings of the Royal Society of London B: Biological Sciences, 278, 2930–8. Ginges, J., Atran, S., Medin, D., et al. (2007). Sacred bounds on Funding rational resolution of violent political conflict. Proceedings of the National Academy of Sciences of the United States of America, 104, This work was supported by the Minerva Program and the Air 7357–60. Force Office of Scientific Research of the U.S. Department of Ginges, J., Atran, S., Sachdeva, S., et al. (2011). Psychology out of Defense (AFOSR FA9550-14-1-0030 DEF) and the BIAL Foundation the laboratory: the challenge of violent extremism. American (Grant #163/14) and the Ministerio de Ciencia, Innovación y Psychologist, 66, 507–19. Universidades (RTI2018-093550-B-I00). Gómez, Á., Brooks, M.L., Buhrmester, M.D., et al. (2011). On the nature of identity fusion: insights into the construct and a new Conflict of interest. None declared. measure. Journal of Personality and Social Psychology, 100, 918–33. Gómez, Á., López-Rodríguez, L., Sheikh, H., et al. (2017). The devoted actor’s will to fight and the spiritual dimension of Acknowledgements human conflict. Nature Human Behaviour, 1, 673–9. 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