9. Animal altruism is most obvious in kin
relationships, but may also be evident among
wider social groups.
10.
11.
12.
13.
14. In “The Selfish Gene”*, Richard Dawkins puts
forth three strategies of reciprocal altruism:
Suckers, Cheats and Grudgers.
*Chapter “You scratch my back, I’ll ride on yours”
15.
16.
17.
18.
19. Let’s say that a bird (B) has a parasite on the top
of his head and needs another bird (A) to remove
it. A pulls it off him.
A is a sucker and grooms others indiscriminately.
20.
21.
22.
23.
24. Later, A has a parasite on his head and seeks out
B in order that B may pay back his good deed. B
simply turns up his nose and walks off.
B is a cheat, an individual who accepts altruism
from others, but never returns it.
25.
26.
27.
28.
29. But now, suppose there is a third strategy
called Grudger. Grudgers groom strangers
and individuals who have previously
groomed them.
However, if any individual cheats
them, they remember the incident and
bear a grudge: they refuse to groom that
individual in the future.