Killing for the Community: The evolution of homicidal self-sacrifice

Suicide Mission: March 8, 2016

At five o’clock in the evening, Fouad Tamimi turned his motorcycle east onto Sultan Suleiman Street on the north side of Jerusalem’s Old City, ready to die.

The young Palestinian sped along the ancient stone wall toward the Damascus Gate, a looming battlement leading into the bazaar between the Muslim and Christian quarters of the Old City. A squad of Border Police were posted at the entrance — probably more than usual, because earlier that day officers had gunned down a 50 year-old Arab woman who had allegedly tried to stab one of them with a serrated steak knife. The story was all over the news that morning. Her blood had barely dried when the Palestinian killer slowed his bike, leveled his Carl Gustav 9mm submachine gun, and opened fire on the Israelis.

One went down, blood spraying. The “Carlo” isn’t the most accurate weapon, but it works.

Tamimi revved his bike and cut left at the next roundabout, directly in front of an Israeli police station, and made his way north up the bustling Salah A-Din Street. Arabs were out shopping or just hanging around storefronts, talking. Security forces closed in on the gunman. Tamimi turned and fired again, hitting another Israeli. Shoppers scattered and scurried indoors. You could hear the shots from the National Hotel, just around the corner, where I was sitting in the dining room.

Reading back through the news stories today, I imagine the intensity of the young man’s experience: heart racing, wind roaring in his face, prayers to Allah on his lips, bursts of adrenaline dumping sugar into his bloodstream, pupils dilating, every sense sharpened, everything moving in slow motion. Years of heroic dreams finally coming to life. The ultimate sacrifice for Palestine, for family, for glory.

For God.

An Israeli officer took aim at Fouad Tamimi, and with a gentle squeeze of the finger created another martyr for the resistance. One soul goes under the surface and a thousand emotional ripples go out. When I arrived moments later, a crowd of Arabs had converged on their brother’s body. They held out cellphones for a few clear shots until an Israeli police unit arrived and pointed tricked out assault rifles at us.

God only knows why some people dive into the jaws of death like it’s good for them.

Self-sacrifice is an evolutionary mystery

Was Tamimi’s suicide attack as insane as it seems, or is there a hidden rationale?

The nasty side of human nature looks sensible in the cold light of evolution. Violent contests are readily explained as another agent of natural selection, where winners take all ova. But martyrdom is an obvious dead end from a Darwinian perspective, at least at first glance. The fearless Eros makes many babies, but a hyperactive Thanatos drive should quickly disappear from the gene pool. So how could a genotype that produces the kamikaze mindset ever survive past the first round?

After years of studying jihadis face-to-face, anthropologist Scott Atran offers a psychological model of the terrorist in his recent article “The Devoted Actor: Unconditional commitment and intractable conflict across cultures.” In Atran’s formulation, the devoted actor’s identification with sacred values — the cognitive patterns which underlay imagined but emotive kinship networks, transcendent laws, and prestigious role models — will surpass any rational assessment of costs and benefits. Consider the dogged Palestinian who holds fast to his right to return to his pre-1967 home, regardless of the material hardships this causes him. The “sacred knot” tying him to the soil outweighs personal concerns.

This hypothesis is amply supported by Atran’s 2010 in-depth study Talking to the Enemy. His grand theory is that the human mind’s susceptibility to these sacred values is an evolutionary by-product: a mental appendix that could fill with hate and explode at any moment. Inborn credulity is the psychological mechanism behind homicidal self-sacrifice.

Although David Sloan Wilson never addresses terrorism directly, the embattled biologist hints at a darker, yet more prosocial explanation for this behavior in Darwin’s Cathedral, published in 2002, and more recently in the brisk 2015 book Does Altruism Exist?. According to Wilson’s controversial group selection theory, the more selfless a society’s members are, the greater its levels of cooperation.

The secular utility of religion is that it suppresses selfishness and encourages cohesion. Upon reaching a certain threshold, this process of social harmonization gives rise to coordinated groups that behave as a single unit. Over time, a population suffused with altruistic individuals will out-compete societies composed of shrewd operators. In this view, Palestine could be conceived of as a single organism, as could Israel, (or Sunni Islam, or Orthodox Judaism, etc.), each consisting of subordinate societal “organs,” such as mosques and synagogues, their veins pulsing with human cells.

Through Wilson’s lens of group-level functional organization, Atran’s devoted actor looks less like an evolutionary glitch and more like a killer bee going down for the hive. Instinctive group loyalty may be the ultimate reason that homicidal self-sacrifice exists.

These cognitive and evolutionary theories represent significant improvements to common explanations for suicide attacks. The usual suspects range from religious fanaticism to economic deprivation to political desperation to psychopathology. Although each may be a contributing factor from case to case, none of them function as complete explanations in themselves.

Scott Atran supplies a critical missing ingredient: devotion to a sacred identity — whether religious or secular — forged in the language of kinship, and adhered to regardless of the prospects for victory. That appears to be what homicidal martyrs are made of. Against all decency, this self-destructive tendency begins to make sense in terms of group selection.

The often sentimentalized propensity for self-sacrifice, coupled with fierce group loyalty, may be the ultimate motivation for suicide attacks against the innocent. Pointing this out isn’t a justification of violence any more than understanding our evolved sweet tooth justifies bulimia. Science is descriptive, not prescriptive.

Hero worship and the sacred family

The practical aspects of altruism are more obvious when the gains are closer to home. W.D. Hamilton’s theory of kin selection, or inclusive fitness, states that if an organism’s instinctive self-sacrifice benefits its genetic relatives, such behaviors confer an evolutionary advantage to the altruist’s genes. Put another way, since one’s siblings and children share (on average) half of one’s genetic code, an instinctive predisposition to fight to the death in order to save one’s family would tend to flourish. The warrior who dies saving his three children will ultimately have more isomorphic genes in the next generation than the coward who abandons his children to death. Even as the distribution of types shifts back and forth, the warrior’s genes will tend to out-compete the coward’s.

In the case of familial loyalty, martyrdom makes perfect evolutionary sense. But do the families of Palestinian terrorists really benefit from aggression?

Before his gruesome end, Fouad Tamimi lived with his family in the Arab village of Al Issawiya, perched atop Mt. Scopus above East Jerusalem. In the hours before his suicide mission, he posted the “10 Commandments for Every Shaheed” (Arabic for “martyr”) on Facebook, which includes: “The shaheed’s mother should not be asked difficult questions about the objective of the attack.” But the Israeli Defense Forces don’t honor such commandments.

Immediately after Tamimi’s attack, his mother and sisters were taken into custody and interrogated relentlessly. Since only his mother had a legal residency in East Jerusalem, the entire family was promptly deported to the West Bank village of Bir Nabala, which is enclosed in the Israeli security fence and guarded by a checkpoint. While many in the Palestinian resistance will surely honor Tamimi’s family, the consequences of deportation will be devastating for them.

This sort of collective punishment is standard procedure in the Middle East. By targeting terrorists’ families, the Israelis hope to discourage rebels who might otherwise have nothing to lose. And yet the attacks continue.

According to Scott Atran’s “devoted actor” model, the immediate family is somewhat irrelevant. Tamimi’s family bonds actually extend far beyond his blood kin — at least in the young man’s spiritual imagination. Atran acknowledges familial loyalty as a strong innate drive, but argues that such tendencies are made malleable by higher cognition. Just as a person recognizes relatives by familiar appearance, shared domiciles, and various linguistic cues, so each of these cognitive modules can be manipulated by uniforms, synchronic religious rituals, and symbolic kinship language. Islamic extremists are acculturated to see fellow Palestinians as “brothers and sisters” and Allah as their universal father.

Atran writes:

[E]xtreme parochially altruistic action occurs and devoted acts are created when self-identity becomes fused with sacred values that provide all group members a similar sense of significance. Important values may influence extreme behavior particularly to the extent that they become embedded and infused with identity and internalized…[P]eople almost never kill and die [just] for the Cause, but for each other: for their group, whose cause makes their imagined family of genetic strangers — their brotherhood, fatherland, motherland, homeland.

These “sacred values” are absolute, beyond considerations of costs and benefit. And they are worth dying for, regardless of the prospects for ultimate victory. In Atran’s estimation, this unshakeable devotion is the crux of Israel-Palestine’s intractable conflict. At its deepest level, the back-and-forth fighting isn’t solely driven by resources and revenge. It’s also driven by the potency of sacred symbols. In fact, Atran’s research team found that when monetary enticements were offered to end the conflict, large numbers of Israelis and Palestinians became even more enraged. These findings include interviews with Israeli prime minister Benjamin Netanyahu and Hamas deputy chairman Mousa Abu Marzook, who balked at material exchanges, but were somewhat receptive to symbolic gestures of reconciliation — at least as an initial move.

A few days before the Damascus Gate attack, my Israeli guide joked that there are no words for “peace-building” or “conflict analysis” in Hebrew. On a similarly macabre note, last summer Fouad Tamimi posted a Facebook pic showing a handful of bullets, adding the wry comment: “The language of dialogue.” An earlier post depicted two masked rebels in keffiyehs clinking Molotov cocktails. The caption read: “To your health, my homeland.”

Evolutionary psychology is often criticized for ignoring the importance of culture, but one of the discipline’s primary tenets is that human babies are born ready to internalize their surroundings through language and imitation. One manifestation of this is “prestige bias,” an innate tendency to imitate those individuals who signal competency and are admired by others in the community. Children follow the leader according to style and reputation. In jihadi youth culture, the role models are suicide bombers.

Nearly a week after the Damascus gate attack, The Jerusalem Post published a misguided op-ed entitled “Personal problems have motivated recent lone-wolf Palestinian attackers.” Citing the Shen Bet intelligence agency, the author claimed that Fouad Tamimi was “known as a thief and a drug addict…not identified with any terrorist group”

The message: Relax. He’s just a punk kid.

If only it were that simple.

Four days later, the Meir Amit Intelligence and Terrorism Information Center published a more comprehensive profile gleaned from the public access panopticon. Scouring Tamimi’s Facebook page, the ITIC compiled a long list of posts that glorify “shaheeds” who have died for the cause. Tamimi was particularly obsessed with Yahya “The Engineer” Ayyash, the Hamas bomb-maker whose efforts inflicted massive casualties until his assassination in 1996. For years Tamimi had been absorbing images of these martyrs, contemplating their methods, and projecting himself into their celebrated roles. It’s become a thriving subculture.

Atran frames the success of this “freedom fighter” archetype in terms of cultural evolution. “[M]ovements that develop psychological mechanisms to promote devoted actors are more likely to succeed because they exploit evolved psychology.” The martyr is a hero who defends “family” and homeland. Atran also identifies the substrate through which this meme virus spreads: “Publicity hyped by political and media frenzy is the oxygen that fires modern terrorism.” This phenomenon is also known as the “copycat effect.”

March 8, 2016 actually saw four separate attacks across Israel — including Tamimi and the 50 year-old woman with the steak knife — confirming fears that a third Intifada is underway. Earlier that afternoon in Petah Tikva, a Palestinian had followed a Jewish man into a convenience store and stabbed him in the neck with a kitchen knife. According to The Times of Israel, the unfaded victim pulled the knife out of his neck, turned it on his assailant, and stabbed the Palestinian to death.

As these news reports lit up the Internet, a knife-wielding Palestinian in Tel Aviv killed a visiting Vanderbilt student and wounded ten others before he was shot by police. As it happens, then U.S. vice-president Joe Biden was meeting with Israeli president Shimon Peres less than a mile away. Biden immediately released an official statement:

I condemn in the strongest possible terms the brutal attack which occurred in Jaffa. There is no justification for such acts of terror.

Cultural leaders demarcate the lines of inclusion and energize opposition. The following day, Hamas spokesman Sami Abu Zuhri wrote on Facebook:

Hamas congratulates the three heroic operations this evening, in Tel Aviv, Jerusalem, and Jaffa, and considers this proof of the failure for all these theories to abort the Intifada, which will continue until the realization of its goals.

Later that afternoon, two brothers armed with a couple of “Carlos” opened fire on an Israeli bus at the Damascus Gate, wounding one person. After an extended car chase, the shooters were “neutralized” in the street.

Throughout Israel and Palestine, branching patterns of grief, rage, and fear connect various sacred families to each successive wound. According to one of Atran’s surveys, roughly a quarter of people in the West Bank and Gaza had watched a fellow Palestinian being injured or killed “right in front” of them, and nearly half knew someone who’s died in the conflict. Although the corresponding numbers are probably lower for Israelis, the emotions are surely as high, and ubiquitous media coverage of terror attacks stokes continual anxiety and animosity — and allegiance to the state of Israel.

This so-called “Intifada of the Individuals” or “Stabbing Intifada,” began to stir around September 2015 and quickly escalated into a steady barrage of kitchen knives, homemade submachine guns, and cars ramming into random pedestrians. The current wave of terror has claimed the lives of 38 Israelis, most of whom are civilians, and has wounded 558 others. On the other side, 235 Palestinians have been killed, mostly alleged attackers, and over four thousand more have been injured.

The disproportionate casualties are striking. For instance, of the four attacks on March 8, only one Palestinian made a successful kill, and he was “neutralized” along with the others. These lopsided bodycounts are easily explained by the Israeli advantage in firepower and coordination. A more difficult question is the persistence of the Palestinian assault. This is best answered by Atran’s hypothesis: the devoted actor, having fused his or her identity with an imagined kin group, will remain true to their sacred values regardless of real-world costs or benefits.

Throughout the Levant, this “Intifada of Individuals” periodically erupts down the fault lines of language, nationality, and religion — delineated by signboard script, physical features, or sacred texts — along which impermeable legal and physical barriers are rapidly being erected. Countless overlapping social networks cover this landscape: impossibly tangled webs of spiritual and political loyalties pulling against each other, each strand coursing with conversation, newsfeeds, and solemn prayers. As the walls grow higher, two distinct groups become more clearly defined.

Self-sacrifice evolves through intergroup competition

The Torah tells us that self-sacrifice means obedience to sacred law. The Gospels glorify it in the crucifixion. The Qur’an demands it in pursuit of the holy struggle. Darwin had his own ideas:

There can be no doubt that a tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to give aid to each other and to sacrifice themselves for the common good, would be victorious over other tribes.

Darwinism is the science of what death leaves behind. If a good historian needs a touch of the sociopath, the study of human evolution requires a temporary suspension of your humanity.

In his landmark 2002 book In Gods We Trust, Scott Atran proposed his theory of religion as an evolutionary by-product. Our ancestors evolved various cognitive biases which originally aided in survival: hyperactive anthropomorphism to detect dangerous agents, a tendency to pay attention to extraordinary stories, and symbolic cognition to think beyond one’s present experience, among others. Taken in combination, these adaptations inadvertently produce a psychology prone to supernatural ideation and susceptible to magical thinking. Through this feedback loop, a wide variety of religious cultures have evolved from the substrate of our cognitive vulnerabilities — for better or worse. Enter the devoted actor.

David Sloan Wilson claims that this propensity for religiosity is for the better. That same year, he offered a remarkably different approach in Darwin’s Cathedral. With a biologist’s eye for adaptation, Wilson asked: How does religion function to organize human society at larger scales? He was struck by abundant metaphors of the religious community as a single organism, as in the body of Christ, the Hindu creation myth of Purusa, or the Hutterite symbol of the beehive. Clearly, the motif of “one emerging from many” resembles the superorganisms found in nature, such as ant and termite colonies. Despite (or because of) religion’s history of cruelty, it became the cultural glue that binds Hominid superorganisms together.

Wilson concludes that religious culture encourages cooperative behavior within groups by suppressing tendencies toward selfishness. Once formed, cooperative groups out-compete non-cooperative groups. This complex schema distinguishes between multiple levels of selection, including genes, individuals, cultures, and groups.

From top to bottom: natural selection favors coordinated groups; these groups are bound by specific types of culture; complex cultures require cooperative minds; cooperation emerges from innate psychological mechanisms; the brain’s mechanisms are expressions of the genes.

At the individual level, innate predispositions vary from highly selfish to highly group-oriented. High frequencies of altruistic individuals arise through an intricate gene-culture feedback loop: the existence of mildly selfless individuals creates a more cooperative social environment; the the social desire for cooperators selects for increasingly groupish individuals; group-oriented people create increasingly cooperative environments, ad infinitum. Of course, this type of environment is also hospitable for selfish free-riders. So long as human kindness endures, social parasites will always be with us.

Collaborating with E.O. Wilson, the godfather of sociobiology, David Sloan Wilson articulated this evolutionary tension between self- and other-regard with the dictum:

Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary.

In a 2008 essay, cognitive psychologist Steven Pinker leveled a scathing critique at this line of thinking. For him, the above process, along with cultural evolution in general, has nothing to do with Darwin’s theory.

“[T]he term ‘group selection’ adds little to what we have always called ‘history,’” Pinker sneers. But he does propose a test: “It’s only when humans display traits that are disadvantageous to themselves while benefiting their group that group selection might have something to add.”

As an example, he chooses the human propensity toward collective aggression. After going over the basic kin selection argument, Pinker casts doubt on the evolutionary viability of any gene that would predispose an individual toward suicide attacks. Instead, he argues that natural selection should favor predatory leaders who are clever enough to manipulate suckers into killing themselves for The Cause.

According to Pinker’s understanding, Fouad Tamimi wasn’t an altruist. He was prey.

But this doesn’t fit what we know about Tamimi, or with Atran’s characterization of the global jihadi movement as a whole. Certainly, terrorists have rallied around central figures, particularly in Al Qaeda, but the dominant profile tends toward self-radicalized young men bound by camaraderie and a common enemy. It is, by and large, a “leaderless jihad” driven by mass-media and celebrated role models. This may not be direct evidence for group selection, but Atran’s research challenges Pinker’s predation model, pointing instead toward a propensity for imitation and identity fusion.

The tendency of unattached young men to emulate terrorists, or “freedom fighters,” is a by-product of otherwise adaptive psychological traits. It is an extreme, media-driven variation on the typical model of territorial young men following their leader into battle to protect the homeland.

In the long view of evolution, these violent tendencies were surely useful for the wider society. Beyond the perennial contest of academic egos, the by-product model and group selection are not necessarily mutually exclusive. The last decade and a half has seen a hesitant synthesis of these theories. Atran writes in Talking to the Enemy:

To kill and die with friends, as in the jihad, almost invariably involves deep love of one’s group. … Groups usually best other groups because they function better as teams. Imagined kinship and friendship may benefit group survival and success by helping to foster teams.

Wilson believes that the deep history of intergroup conflict, going back to the earliest Hominids, drove both genetic and cultural evolution toward intragroup cooperation. The more selfless warriors a tribe produced, the greater its chances of victory. Defectors might do well for themselves against the interests of other group members, but the technical term for an army of defectors is losers.

Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary.

Communal values produce suicidal killers

The Qur’an and the Torah are loaded with injunctions to embrace kinsmen and eliminate outsiders, as is The Communist Manifesto. At the group level, such sacred texts function as a sort of “cultural genome” from which various ideologies, ways of life, and institutions may be selectively expressed. These constrained cognitive patterns define the ingroup, erect reproductive and territorial barriers, and demand the fair treatment of “brothers and sisters” within the “cultural fortress” — so long as they behave. These belief systems also give license to destroy foreign entities who threaten to breach the wall.

Under the selective pressure of intergroup conflict, the most successful biological genotypes will be those that program for the development of cognitive mechanisms that produce altruism. And if a social collective out-competes its neighbors, both the cultural modes and the genotypes of that culture’s members will be preserved.

This genetic component is the most controversial aspect of Wilson’s theory, but also the most consequential. If intergroup conflict drives population frequencies toward increased altruism, there will be outliers in any given society with an innate propensity toward extreme altruism. I suspect that this selfless disposition interacts with other psychological mechanisms, such as kin preference, territoriality, and aggression.

A normal warrior will weigh risks against the urge to rape and pillage, and will potentially admit defeat. But as nature shuffles the deck, there will always be those who are willing to destroy themselves — and as many enemies as they can take with them — for sake of the tribe. We see this in kamikazes and Tamil Marxists, and even in mass shooters, whose manifestos often reveal a warped sense of social concern.

Atran provides a psychological mechanism. Wilson suggests its original evolutionary purpose.

The light and dark elements of the soul are intertwined down to our nucleotides, permanently embedded in the human condition. Perhaps a strong saint instinct is the critical difference between a stubborn devoted actor who refuses to leave home and a full-blown suicide bomber. If so, terrorism goes far beyond poverty and radical politics.

As long as “sacred knots” bind young men to blood, soil, and spirit, eruptions of homicidal self-sacrifice will be inevitable whenever existential threats are perceived. A deep, empathic knowledge of this psychology is the key to forgiveness and reconciliation — or, at the very least, it opens a more sure-footed route to stamping out your enemies.

Wartime altruism isn’t just Florence Nightingale. It’s also Fouad Tamimi.