Warfare then and now

On pages 358-9 of his chapter "The Fall of the Hunnic Empire," Peter Heather writes, ". . . the only coherent narrative is to be found in the Getica, which of course presents it as a triumph for the Amal-led Goths.  As Jordanes tells it, these quickly came to blows with the Suevi, over whom they won a great victory.  The Suevi then stirred up the other regional powers against the Goths, particularly the Sciri, who managed to kill Valamer in the first bout of fighting.  The Goths, however, took a ferocious revenge, destroying the Sciti as an independent power.  This led most of the rest -- the Suevi, the remaining Sciri, Rugi, Gepids, Sarmations 'and others' -- to unite against the Goths.  The result was a second great battle, on a second unidentified river in Pannonia, the Bolia, where as Jordanes tells us:

"the party of the Goths was found to be so much stronger that the plain was drenched in the blood of their fallen foes and looked like a crimson sea.  Weapons and corpses, piled up like hills, covered the plain for more than ten miles.  When the Goths saw this, they rejoiced with joy unspeakable, because of this great slaughter of their foes they had avenged the blood of Valamer their king."

Could a modern Western European rejoice "with joy unspeakable" over the sight of "corpses piled up like hills" and if not why not?  Up until recently we might have leaned toward thinking it a matter of culture and education.  Hitler and his Nazis might and probably did rejoice in that way, but we explain Hitler as a charismatic aberration and not at all like the more modern Germans who survived his excesses.  Smaller excesses such as those at Abu Grahib or the activities of Blackwater Mercenaries cause the modern Westerner outrage -- no "joy unspeakable" at the humiliation of a foe.

But we saw another culture, a culture that wants to behave in accordance with dictates established in the seventh century rejoice with joy unspeakable after the Twin Towers were destroyed.  Not all cultures in the world have moved from attitudes like the Goths.  I was among those who believed (and perhaps most still believe) that fifth century Gothic and 20th and 21st century Islamist excesses must be overcome by means of education and changes in culture.  However Nicholas Wade writes in location 1702 (I'm reading it in Kindle) of A Troublesome Inheritance: Genes, Race and Human History ". . . some 10,000 years ago . . . Independently on all three continents, people's social behaviors started to adapt to the requirements of living in settled societies that were larger and more complex than those of the hunter-gatherer band.  The signature of such social changes may be written in the genome, perhaps in some of the brain genes already known to be under selection.  The MAO-A gene, which influences aggression and antisocial behavior, is one behavioral gene that . . . is known to vary between races and ethnic groups . . . ."

We can imagine how Natural Selection might not favor the MAO-A gene.  People who killed their neighbors, killed people on the highway in road-rage, blew enemies up with bombs strapped to their bodies, and those who join mercenary groups to fight around the world won't be having as many children as those without this gene.  In the meantime our laws prohibit aggression and antisocial behavior so if you have the MAO-A gene, too bad for you.