The Meme Machine

A MEMETIC THEORY OF ALTRUISM 151
tournament and asked computer programmers to submit strategies for playing
the game. The fourteen entries each played 200 times against all the others,
themselves, and a random program. To many people’s surprise, the winning
program ‘Tit-for-tat’ was both simple and ‘nice’. Tit-for-tat began by
cooperating and then simply copied what the other player did. If the other
player cooperated then both continued to cooperate and both did well; if the
other player defected, Tit-for-tat retaliated and so did not lose out too badly
against defectors. In a second tournament over sixty programs tried to beat Titfor-tat
but failed.
Subsequent research has used more complex situations, with many players,
and has been used to simulate evolutionary processes. It turns out that unless
Tit-for-tat begins against overwhelming numbers of defecting strategies, it will
spread in a population and come to dominate it. It is what is known as an
‘evolutionarily stable strategy’. However, the real world is more complex, and
Tit-for-tat does not do so well when mistakes are made, or when there are more
players and more uncertainty. Nevertheless, this approach shows how group
advantage can emerge out of purely individual strategies without the need to
appeal to evolution for the ‘greater-good’.
Is this how cooperative behaviour actually evolved? If so it would need
some kind of nice behaviour to get it started, and Trivers has suggested that kin
selection might have provided the starting point. Animals already supplied with
feelings of affection and caring towards kin could easily begin generalising and
so give nice Tit-for-tat the start it needed.
Note that the Prisoner’s Dilemma is a non-zero-sum game. In a ‘zero-sum’
game what I gain you lose, and vice versa. This is not so for many real-life
situations. Half a blood meal means life or death to a hungry young vampire bat
but no more than an easy way to buy future favours for a well-fed more
experienced hunter. This exposes the rather unpleasant concept of bargain
hunting – giving deliberately to others who are in great need because their debt
to you will be all the greater. This approach has also been used to show how
moralising might evolve, since it pays to punish defectors and even to punish
people who fail to punish defectors. In this kind of game, trustworthiness
becomes a valuable currency. It pays you to be seen to be cooperative because
you may reap the reward at some later date.
I have given only a few examples of how sociobiology has dealt with the
problem of altruism (more extended treatments can be found in Cronin 1991;
Matt Ridley 1996; and Wright 1994) but I hope these are enough to see just how
successful it has been. In a sense this approach takes the altruism out of