And forgive us our debts, as we forgive our debtors.
Matthew 6:12 (King James version)
suckers, grudgers and cheats
During the 1980s, various models of hypothetical populations started to be run as simulations on computers. One useful way of classifying the way members of a society interact
with each other is by sorting them into suckers, grudgers or cheats.
This is a classification after Maynard Smith, popularised by Richard Dawkins in his book The
Selfish Gene pp.184-185, built on watching grooming behaviour of birds
carrying harmful parasites.
These were birds that helped each other in an apparently altruistic
way, but refused to help - bore a grudge against - individuals that
had previously refused to help them. Grudgers came to dominate the
population because they passed on more genes to future generations
than either Suckers (who helped others indiscriminately, and were
exploited) or Cheats (who tried ruthlessly to exploit everybody, and
ended up doing each other down).
Notice that such strategies depend heavily upon individuals being able to recognise other individuals apart, and to remember the individual and its/their behaviour. This has obvious and different implications for those living in small villages and groups contra those living in large and somewhat anonymous cities.
suckers, grudgers and cheats
Imagine a population of creatures that has three varieties of individuals:
suckers, cheats, and grudgers.
At first, all of these individuals co-exist
in equal numbers, but eventually the number of grudgers will increase
until they dominate the population. This occurs for a number of reasons.
- Suckers end up helping everyone indiscriminately and they end up being
exploited shamelessly by others.
- Cheats take as much as they can get
from everyone and rarely reciprocate anything. The “cheat”
strategy is profitable for a while, but as the number of suckers diminish
and as the cheats are found out, they become less successful.
hardiest survivors are the grudgers, who continue to help those who
help them but refuse to cooperate with cheats.
- The cheats first eliminate
the suckers, but they in turn are then eliminated by the grudgers.
Hence, even though an altruistic behaviour being performed in the present
may prove beneficial to only one of the individuals involved, under
a system of reciprocal altruism the other person will eventually be
repaid in kind.
We saw how, in the example of mutual grooming, if there are only
suckers and cheats around, the strategy Cheat is evolutionarily stable,
while the strategy Sucker is not. Now introduce a third strategy,
A grudger is rather like you and me. A grudger grooms anyone
who has previously groomed him, and any stranger, but he remembers
and bears a grudge against anyone who cheats him - who refuses to
groom him in return for having been groomed - and the grudger refuses
to groom the cheat ever again. Now when all three strategies are in
play, both Cheat and Grudger are evolutionarily stable. In a population
consisting largely of cheats, the cheats will do better than the others,
and both suckers and grudgers will die out. But in a population that
starts off with more than a critical proportion of grudgers,
the cheats will first wipe out the suckers, but will then themselves
become rare and eventually extinct: Cheats can flourish only while
they have suckers to take advantage of, and yet by doing so, they tend
to eliminate those suckers.
It is obvious, by the way, that a population containing only suckers
and grudgers, in any proportions, but no cheats, would simply continue
as it was. Suckers and grudgers behave exactly like one another as
long as there are no cheats around, so there would be no tendency
for either the Sucker of the Grudger gene to do better than the other.
But if there is any risk of an invasion of Cheat genes, either through
mutation or through immigration, such a pattern is not evolutionarily
stable, and the higher the proportion of suckers, the more rapidly
the cheats would multiply.
Another name for grudgers is ‘reciprocal
altruists’. They act as if on the maxim ‘Be done by as
you did’, also see 'tit for tat' in The Evolution of Cooperation (see especially pp. 27-54). One implication of this story is that this strategy
is not only evolutionarily stable within a population, it is also
viable for a population as a whole. The explanation of the final situation,
where all birds of this species are grudgers, lies partly in the non-viability
of a population of pure cheats.
chapter 7, the problem of moderation
- A word of warning. All such simulations are crude simplifications of the real world. Various game-playing models have been run competitively against other attempts, and it is found that 'nice' tend to defeat 'nasty' models of co-operation or defection.
This can be seen in paranoid behaviour, which tends to evoke aggression in others. The paranoic, being distrustful, behaves in a negative manner to other people. This tends to evoke negative behaviour in others, thus reinforcing the original paranoia. So being nice tends to be a winning strategy, whereas being nasty, in general terms, tend to be a loosing strategy. Even forgiveness, up to a point, is likely to improve your relationships and your society.
Machiavelli advises the Prince, "Do not do small harms to people, but if you are going to do harm, do great harm
whereby the opponent is no longer in a position to harm you." In other words, to kill them. This is not a strategy which tends to develop successful and happy societies as you can note from observing dictatorships and dictators, or even the lives of lower-scale murderers and violent people.
- tit for tat
- Tit-for-tat is an attempt to model a part of human behaviour. Human behaviour is far more complex than a model suggests. This sort of modelling is sometimes applied to a problem situation known as the prisoner's dilemma. A common example is when police try to get two or more 'suspects' to each rat out on the other/s. The police may promise each person their freedom if they are the first to rat out, while threatening that if another suspect can rat them out first, it is the current interviewee who risks a ten-year sentence. Of course, this puts great pressure on people to fit up one another, the objective of the police. This ploy is often called 'plea bargaining', and clearly is a very dangerous practice.
In modelling,the actual numbers in the the table try to define the relative pay-offs for the prisoners (suspects). Here is a typical pay-off table:
|the prisoner's dilemma
Reward for mutual
Sucker's payoff, and
Temptation to defect.
Temptation to defect, and
A tit-for-tat operator always starts by co-operating. When an entity does something/not liked/unpleasant/costly to another (tat), the other person/recipient then does the same action back (tit). That is the end of the incident.
If the actions continue, the process can be called a blood feud.