Theology and Evolutionary Psychology, Chapter 8: Vengeance Psalms and the Dark Side of Reciprocity

In the last post we looked at the good side of reciprocity, the role it plays in fostering cooperation. Today we'll look at the dark side of reciprocity: Vengeance and revenge.

Communal reciprocity (the Pay it Forward World I've written about) is vulnerable to the free rider problem. Free riders are those communal cheats who take advantage of the communal reciprocity norm. That is, they take and take and take but never do they reciprocate (hey, that rhymes).

Free riders are a threat to the Darwinian equilibrium that selects for reciprocity. That is, if free riders are globally successful in exploiting those who share then the free riders will eventually out-compete their neighbors. Reciprocity would be a less successful strategy than free riding and, thus, free riding will proliferate causing reciprocity to vanish.

But reciprocity doesn't vanish because it has a dark side. The positive side of reciprocity is the familiar "you scratch my back and I'll scratch yours." But the dark side of reciprocity is "an eye for an eye and a tooth for a tooth."

The good side of reciprocity is cooperation and sharing. The dark side of reciprocity is revenge and vengeance.

Revenge and vengeance are adaptive because they evolved to deal with the free rider problem. That is, due to the dark side of reciprocity free riding is costly if not dangerous. In the literature, punishing cheaters and free riders is called moralistic aggression.

The point here is that moralistic aggression is intimately tied up with our sense of justice (it is called lex talionis, or the law of retribution). Thus, when we experience moralistic aggression we feel justified in acting aggressively and vengefully. Moralistic aggression feels, due to our evolutionary history, very natural and normal to us. Very moral and right.

Moralistic aggression is common in the bible. The easiest place to see it is in the vengeance psalms. For example:

Psalm 109: 1-15
O God, whom I praise,
do not remain silent,
for wicked and deceitful men
have opened their mouths against me;
they have spoken against me with lying tongues.

With words of hatred they surround me;
they attack me without cause.

In return for my friendship they accuse me,
but I am a man of prayer.

They repay me evil for good,
and hatred for my friendship.

Appoint an evil man to oppose him;
let an accuser stand at his right hand.

When he is tried, let him be found guilty,
and may his prayers condemn him.

May his days be few;
may another take his place of leadership.

May his children be fatherless
and his wife a widow.

May his children be wandering beggars;
may they be driven from their ruined homes.

May a creditor seize all he has;
may strangers plunder the fruits of his labor.

May no one extend kindness to him
or take pity on his fatherless children.

May his descendants be cut off,
their names blotted out from the next generation.

May the iniquity of his fathers be remembered before the LORD;
may the sin of his mother never be blotted out.

May their sins always remain before the LORD,
that he may cut off the memory of them from the earth.

Psalm 137
By the rivers of Babylon we sat and wept
when we remembered Zion.

There on the poplars
we hung our harps,

for there our captors asked us for songs,
our tormentors demanded songs of joy;
they said, "Sing us one of the songs of Zion!"

How can we sing the songs of the LORD
while in a foreign land?

If I forget you, O Jerusalem,
may my right hand forget its skill .

May my tongue cling to the roof of my mouth
if I do not remember you,
if I do not consider Jerusalem
my highest joy.

Remember, O LORD, what the Edomites did
on the day Jerusalem fell.
"Tear it down," they cried,
"tear it down to its foundations!"

O Daughter of Babylon, doomed to destruction,
happy is he who repays you
for what you have done to us-

he who seizes your infants
and dashes them against the rocks.

This language is shocking, but we can identify with it. We get it. We understand what it feels like. Thus, when we read or watch A Time to Kill, we understand the father's actions. They don't need to be explained to us. We find his anger completely comprehensible. We sympathize with him. And we feel, in our bones, that the father was justified in what he did. The entire novel and movie is leveraging off of our Darwinian moral psychology. Without an innate sense of moralistic aggression the movie loses its psychological core.

That feeling, that A Time to Kill dynamic, is the morality of our Darwinian heritage. And like we've seen in the last few posts, Jesus keeps pinpointing--like a heat seeking missile--the very tenets of our Darwinian morality and pushes us to transcend them. We have already seen Jesus hit kin selection and reciprocity. Here's his take on moralistic aggression:

You have heard that it was said, 'Eye for eye, and tooth for tooth.' But I tell you, Do not resist an evil person. If someone strikes you on the right cheek, turn to him the other also. And if someone wants to sue you and take your tunic, let him have your cloak as well. If someone forces you to go one mile, go with him two miles. Give to the one who asks you, and do not turn away from the one who wants to borrow from you.

You have heard that it was said, 'Love your neighbor and hate your enemy.' But I tell you: Love your enemies and pray for those who persecute you, that you may be sons of your Father in heaven.