Aggression IV. 102m Robert Sapolsky video.

Part 4 of 4 in a broad biological survey on empathy and aggression and the biological roots of human morality. Sapolsky begins by adding more detail to the discussion of perinatal effects on aggression. Then he covers the effects of genes. He predictably argues that the gene-environment interaction makes it difficult if not impossible to differentiate genetic effects. Then he gives an in depth exploration of cultural, ecological, environmental, and evolutionary effects. He concludes poignantly reminding us that the same exact behaviors can win medals or be the most horrific thing one human being can do to another.

20. Aggression IV

Perinatal Development

Organizational hormonal effects ("setting up the nervous system to respond later on to some sort of activational hormonal effect") vs. activational effects. Rodent studies of female androgenization (exposure to high levels of perinatal testosterone) show that there is a strong organizational effect resulting in more aggressive play, aggression, and less maternal behavior (activational effects) even with low adult testosterone levels. In primates, the patterns are strong but less dramatic than in rodents. In humans, female fetuses with congenital adrenal hyperplasia or those exposed to the drug DES (diethylstilbestrol) are androgenized. The literature suggests that there might be some hints of effects, but the confounds make the literature uninterpretable in Sapolsky's view.

Simon Baron-Cohen has developed the hypermale hypothesis of autism. Autism occurs more often in males. For problem-solving, males tend to use more analytical approaches to social problem-solving; females use more empathic approaches. The finger-length ratio (ratio between the length of the second and the fourth fingers), stronger spatial skills, the analytical problem-solving approach are all more pronounced in autistics. That is, normal male behavior verges on the pathology of autism.


It used to be offensive to suggest that genes could have anything to do with aggression (pickets and NIH funding restrictions and all that). Since hormones and receptors are all built from information in the DNA, genes can have a definite effect on behavior. But how do we distinguish a gene having to do with impulsivity versus one dealing with aggression? Since pain is a reliable releasing stimulus for aggression, the gene might have something to do with pain and not aggression. If the gene for general sympathetic nervous system arousal is more enhanced, in addition to more aggression you also see more affiliative behavior. Most of the early studies identified genes with indirect causes for more aggression.

Some genes have held up to very careful studies (namely, the serotonin synthesis and receptor genes and dopamine receptors). The effects are modulatory and subject to the environment early in life (mainly if there was abuse or stress). This is to be expected because all genes are subject to the gene-environment interaction where the genetic behavior only makes sense given its environmental context.

Sapolsky expects that the emerging field looking at different genotypes in different populations will soon be very interesting. But he doesn't feel it is mature enough to report on yet.

Even if we have identified genes increasing predisposition to aggressive behavior in some environmental context, we have no biological means to predict who will become a sociopath and who will become an aggressive monopoly or chess player. Just as we can't predict which person with damage to their frontal cortex will become a sociopath and which will be an annoying piano player.

Richard Speck broke in to the apartment of 8 student nurses in Chicago and slaughtered them in 1966. It was erroneously discovered and reported that Speck had 47 chromosomes (XYY karyotype). This started a mania about XYY and violence which proved to be totally unfounded. Aggression is no greater in XYY than normal XY males. More evidence that we ought not overvalue the genetic evidence.

Ecology & Culture and Aggression

Nomadic pastoralists (in contrast to traditional hunter/gatherers and farmers) have higher rates of violence (both in-group and out-group), more likely to have standing armies and warrior classes, leadership tends to come from the warrior class, and religions where success in war is a gateway to heaven. It makes since since animals need to be protected and groups can be widely dispersed. The American South was disproportionately settled by sheep herders from the Northern British Isles (nomadic pastoralists). These are cultures of honor: clear rules about triggers for aggression over symbolic slights. The higher murder rate in the American south occur in rural places among people who know each other (not in cities, not crimes for material). Richard E. Nisbett did a study to assess the differences in southern vs. northern culture in males: a confederate bumps past the subject in the hall and says "watch it asshole". The subject then goes into the study where their blood pressure and other physiological factors are tested. Northerners brush it off, Southerners have a massive stress response with high blood pressure and elevated stress hormone & testosterone levels.

Desert dwellers (who invented monotheism) and those living on open savannah grasslands tend to be nomadic pastoralists and they have higher rates of violence compared with rain forest dwellers who tend to be polytheistic and hunter/gatherers or small-scale farmers.

Those with cultural myths of victimization with an ethos of retribution tend to be more violent.

Altruistic punishing can be modeled in a game by giving the option of spending some of your resources to punish a cheating participant. In a study across many cultures of university students, on average everyone spends about the same amount to punish cheaters. Antisocial punishment is where someone is punished for having been overly generous. The US, UK, and Scandinavian participants had the lowest rates of antisocial punishment; middle eastern countries and Slavic countries of the eastern block, Korea, and Turkey were in the middle; the worst such punishers were in Greece and the United Arab Emirates (UAE) where more punishment went to generous players more often than to cheaters. Why? If people started being generous it will up the ante for everyone. A deeper factor is the level of social trust (social capital) in the society.

What are the cultural and ideological environments that give rise to terrorism? Some view it as abnormal sociopathic behavior (individual dysfunction: neuropsychiatric), others view it as ideological extremes. There tends to be a consistent profile of terrorists (from the Boston Tea Party, the IRA, the Haganah in Israel): young, male, socially isolated, socially unaffiliated, relatively uneducated, history of childhood abuse. If they hadn't joined the terrorist group, they would be mugging old ladies. Middle Eastern terrorism follows a completely different profile: educated, well off people in their 30s and 40s (not young men), middle or upper class backgrounds, more women than in any previous kind of terrorism, individuals who tend to have no prior exposure to the oppression which they are fighting against, and relatively low levels of religiosity. Very surprising. Phil Zimbardo (who did the famed Stanford prison study) argues that under the right circumstances virtually anyone can do anything that is appalling. Another view is that because modern terrorism is international, only the better educated are able to get passports, navigate customs, and fly elsewhere.

Evolutionary Influences of Aggressive Behavior

In the vast majority of social species and in all human cultures, the major cause of aggression is "male-male violence over reproductive access to females". The Yanamamo have been intensely studied for decades (principally by Napoleon Chagnon). Chagnon published a highly controversial article in Science backed by decades of data that the more violent males have higher reproductive success (Sapolsky doesn't think the statistics are valid). Orangutans and other species including humans have rape. Is rape more about passing on copies of your genes or power and subjugation? Sapolsky's assessment of the field is that (except for Orangutans) it is mostly about power and subjugation.

The second most common cause of human aggression is males attacking females over denial of sexual access. The individual selection explanation applies: for a male to pass on copies of his genes he needs a "willing" female. Individual selection also accounts for female-female aggression, infanticide, and competitive infanticide.

Kin selection ("I will gladly give my life for 2 brothers or 8 cousins" as attributed to Haldane) accounts for why related individuals cooperate in circumstances of aggression. Chimps have female exogamy, so all the males in a chimp group are related and so they cooperate with each other resulting in warfare and even genocide. In most primates, kin selection explains why aggression is mainly between lineages (not within).

In humans, there is a much more fluid sense of "relatedness" or "us vs. them". A Bedouin saying explains: "It's my brothers, my cousins and I against the world; and it's my brothers and I against my cousins" (different translations are seen on the net). Humans have a relative sense of relatedness.

Daly and Wilson use a kin selection argument to explain why step-parents are more likely to abuse their stepkids than their biological father; a child is more likely to be abused by their paternal grandparent than their maternal grandparent (due to the greater certainty of paternity). Problems: the Scandinavians cannot replicate these findings. It could be that economic stress increases violence (families with step fathers tend to have more economic stress).

Do we have prepared learning to see some us/them dichotomies better than others? Very controversial: what categories do kids divide people into? Are kids colorblind (skin color-wise)? Do they distinguish on other body characteristics?

Pseudokinship: people who feel as closely connected to each other as they would to their relatives. In military indoctrination a highly developed faculty has developed for making some people feel more related to each other than they actually are: one of the main points of military training is to forge a "band of brothers" to increase cooperation (that is, to increase the chance that you will give up your life for the person next to you).

The Maasai people in East Africa are a warrior culture that begins military training at 15 (it lasts 10 years). They live separately from everyone else, use kinship terms to refer to each other, share food with fellow warriors, and protect the herds and raid other villages. After they leave the military and get married, his wife will refer to members of his warrior cohort as her brother-in-law. The Israeli military allows a cohort of friends to join the same unit to increase pseudokinship.

In WWII, the heterogeneity of US troops meant that those of German ancestry were more related to the people they were fighting against. In Vietnam, there was a major failure of US military pseudokinship: the military moved people around so that no one was kept in a stable fighting unit. Apparently, this was done to reduce the high rates of soldiers shooting their officers.

Pseudospeciation: psychological mechanisms to make others seem so different from us that you don't even view them as human. Take Adolf Hitler, Osama bin Laden, Idi Amin Dada, Pol Pot, Heinrich Himmler, Adolf Eichmann, or Jim Jones: were they human? Do they deserve the same moral considerations as other human beings?

Examples include US WWII propaganda about ethnicities we were fighting, the 1994 Rwandan Genocide had the call to arms of "Kill the Cockroaches" (the Hutu killing the Tutsi). Another example was the Nayirah testimony in the run-up to the 1991 Gulf War which claimed that the Iraqis had removed the Kuwaiti babies from incubators to die: they aren't even human. The story was fabricated and pushed by PR firm Hill & Knowlton who was paid about $11 million by the Kuwaiti government, the measure to support military action passed by only 3 votes with 7 senators citing the fabricated story in their votes, and we went into the war with a 92% approval rating. A gigantic piece of pseudospeciation manipulation: "my god they leave babies out to die ... they are hardly even human".

After the break, Sapolsky summarizes: we've seen how individual and kin selection lead to more aggression. What evolutionary selective mechanisms lead to more cooperation, empathy, affiliation, and less violence?

In individual selection, there are alternative male strategies (be nice if you cannot be dominant). South American pair-bonded monkeys have low rates of aggression (in contrast to tournament species). Pseudokinship can also be used to decrease violence by making people feel more connected to each other. Examples of pseudokinship to support peace: in a traditional Bedouin society peacemaking effort, the rival clansmen start exploring each others' geneology until one party transparently fabricates a story about a common ancestor (aha, we're related, let's make peace). In Australian aboriginal groups when two individuals approach a water hole they start sharing their geneologies when "oh, we're relatives". Again it is a transparent effort at pseudokinship to share a vital resource without violence. After revolutions, the two sides are viewed as brothers reuniting: using pseudokinship terms. After the French revolution everyone addressed each other in the familiar tense instead of the (illegal?) formal tense.

Elizabeth Phelps at NYU showed using fMRI that there is subliminal activation of the amygdala when a picture is flashed of someone of another race (it has been replicated a number of times). The amygdala sees us v. them in a split second. Susan Fiske at Princeton found that if some of the pictures have a big red dot and you are asked to tag them, then the amygdala does not activate on pictures of people of another race. Ask subjects to categorize the photos as below or over age 30 (treat the images as a category not an individual), now the amygdala is even more activated (us v. them priming). Finally, ask subjects to identify individuality in the photos (do they like coke or pepsi?), then the amygdala does not activate. The amygdala does not activate in people who grew up in racially and ethnically diverse neighborhoods nor for people who had a significant relationship with someone of another race.

Contact theory: aggression is decreased and affiliation is increased if you grow up with lots of contact with people from other cultures. It broadens one's sense of what is an "us". But studies have shown that if you send kids from different cultures to retreats or summer camps or other short programs together, the pseudokinship only lasts for a short while. To get a lasting inclusive "us" it is necessary to grow up in (or live for a long time in) a diverse community. More interfaces of contact between two groups doesn't guarantee less amygdala activation (less us vs. them).

Aggression can be increased because of the spatial characteristics of the interface between the two populations (there are regions where irritation, resources contention, and pockets of local unity can heighten us vs. them conflict instead of pseudokinship). The least optimal community interfaces predicted the locations of violence in the Balkans (Sapolsky only mentions Croatia & Bosnia, but there ware wars in Slovenia, & Kosovo in the 1990s too). I searched for but could not find the study Sapolsky cites. Do you know where it is?

The neurobiology of symbols in our brains can foster cooperation. Robert Axelrod at U Michigan has been showing the importance of symbols in peacemaking: being respectful of the other side's symbols makes it easier to share contested resources. "The power of symbols over rational contested resources."

Sinn Féin sent a 50th wedding anniversary gift to Ian Paisley which led to a massive breakthrough in Northern Ireland peace negotiations. The film Invictus shows how Nelson Mandela spent his time in prison becoming fluent in Afrikaans to build pseudokinship in negotiations to end apartheid. Mandela would invite the most difficult negotiator to sit next to him and offer especially considerate hospitality. Axelrod finds that Palestinian leaders say "if the Israelis would just once admit that the Palestinians got screwed in 1948 and we're sorry, then we'd be willing to make peace" and that Israeli generals say "if the Palestinians would just get the anti-semitic garbage out of their schoolbooks, we'd be willing to make peace". Respecting symbols and the legitimacy of the history is more important (and sometimes more difficult) than sharing the contested resources.

I think Sapolsky is slightly misusing Garrett Hardin's "tragedy of the commons" here. A tragedy of the commons occurs when a common pool (shared) resource is knowingly and regretfully but unavoidably degraded by a community. Sapolsky is exapting the term to apply to broader competitive situations as well.

How can cooperation evolve? In the prisoner's dilemma (a game designed to show why cooperation might fail even when it is in both parties' best interest) the tit-for-tat strategy starts off cooperating and then either cooperates or defects based on the other player's last action. One way to get cooperation going is with a founder population who due to kin selection in a geographically isolated area develop cooperation which they can introduce and fix in the larger population because of its competitive benefits (this is the modern version of group selection). The phenomenon generalizes: whenever a cooperating population emerges amid a sea of non-cooperators, there is competitive pressure for cooperation. In New York City in the 1980s, Korean and Lebanese immigration increased. The Korean community opened many fruit/vegetable stands and the Lebanese regular grocery stores. The community of extant groceries complained that they were at an unfair disadvantage because the owners of the immigrant groceries were cooperating with each other with low-interest loans and other help. A community of trust can outcompete the previously entrenched larger non-cooperative population. "Those people are cheating, they are cooperating with each other, so either join in or you will be driven to extinction."

Important factors in fostering cooperation in game theory: 1) repetition: with repeated rounds punishment for cheating increases the chances for cooperation to start. Sapolsky emphasizes that the number of rounds cannot be known beforehand. If we all know this is the last round, then there is no "shadow of the future" to encourage cooperation and cheating is strategically justified. But knowing everyone will cheat in the last round, they will cheat in the second to last round and indeed all rounds will quickly succumb to the strategic cheater. 2) open book play: other players can know your record from previous rounds. Reputation encourages cooperation. 3) multiple unsynchronized games: there can be a psychological bleedover from cooperative games into other games where it would be less likely to develop (more like the real world). 4) altruistic punishment: if you can expend some of your resources to reduce their resources, then cooperation is more likely to emerge. 4) second party altruistic punishing: if an independent 3rd party can punish cheaters (an outside enforcer), cooperation is more likely to emerge even faster. 5) Secondary altruistic punishing: if an outside enforcer doesn't punish a cheater, the parties can punish the outside enforcer and cooperation can emerge even faster still (expectation of reporting honor code violations). 6) Secession: if a party can withdraw (secede) from a dyad (a pair of players) or from the whole game, then cooperation can emerge even faster.

Sapolsky cautions cooperation doesn't always lead to less aggression. Indeed when kin selection results in Chimpanzee males building strong cooperation, you end up with border patrols and even genocide. One of the scariest things on this planet is when a bunch of males start cooperating seriously because then they start to look at their neighbors. It seems that a prerequisite for genocide between groups is a reduction in homicide within a group. Does the decreasing homicide rate in the US put us at risk for committing the next genocide?

Sapolsky then tells stories of cooperation emerging in the trench warfare of WWI. On Christmas day 1914 a truce was agreed. Troops from both sides emerged from the trenches to play soccer, exchange gifts, singing and drinking. The officers couldn't get the troops to return to their jobs of killing each other for a few days. But that is an outside force establishing the cooperation. In WWI spontaneous cooperation ("truces") also arose between the two sides. How do you generate a reciprocally altruistic relationship with the enemy troops hidden from view in the next trench over who don't even speak my language? You have your best gunner fire repeatedly at the same tree 20 yards beyond the trenches. This communicates, our guy is really good and we are choosing not to put it in your trench. If the other side has their best gunner do the same thing, you now have a flaming war with shells constantly exploding but no one getting hurt due to the spontaneously negotiated non-aggression pact. The phenomenon is well documented and developed multiple times along the fronts of WWI. The only thing that stopped it from spreading was orders from higher up to attack or face court-martial.

Sapolsky ends poignantly. He tells of the 1979 story of when he was about 21 in the first year of his graduate research in East Africa. At that time Uganda's nightmare dictator Idi Amin miscalculated a border intrusion into Tanzania which resulted in the Tanzania army counterattacking and liberating all of Uganda forcing Amin into exile. The day after the Tanzanians gained control of the southern part of Uganda by reaching the Kenyan border, Sapolsky decided to tour the war zone in Uganda. He figured seeing some violence would do good things for his 20 year old brain neurochemistry. After getting sufficiently scared, he decided to leave once he visited the source of the White Nile in a town he calls Tororo (but I don't see why he thought it the source of the white nile; maybe he meant Jinja, Uganda?). He tells of seeing a Ugandan soldier whose bloated body was tossed by the waves with his hands tied behind his back, strangled, and drowned. He felt a storm of emotions: "good, that's what you deserve being in Amin's army. No, wait a moment, this was probably some poor guy who was forced to do it. And thinking, no, I know what I think of soldiers who are just following orders. And thinking I ought to get a lot closer to see what is happening. And thinking, no, I better get as far away from here as possible." He stood there for an hour and half until some Tanzanian soldiers chased him away.

33 years after witnessing the dead Ugandan soldier, Sapolsky thinks he lectures longer and longer about aggression because of that soldier in Uganda: rational, professorial people who respect thought and think if you lecture on a subject long enough it will go away and will cure world aggression: "if only people can be lectured about the frontal cortex it will solve world violence. ... But the problem is that aggression is such a messy set of behaviors ... the same exact behaviors and depending on the context it could be something that could get a medal for someone, someone you'd want to mate with, vote for, reward, cheer on, join in, and in another setting it is the most frightening possible thing that can happen to us. And it is the same behaviors in all those cases. ... Violence is always going to be the hardest subject for us to understand biologically. And for that reason that it's always going to be the one we have to try hardest to understand."