Lecture 16- Cooperation and Conflict Nov.10/2016
Whether a particular social behaviour represents cooperation, competition, spite or
Social interaction is classified based on recipient fitness and actor fitness. The recipient is the one
receiving the behaviour, the actor is the one behaving. Selection acts depending on if the fitness of the
actor increases or decreases.
Actor fitness increases Actor fitness decreases
Recipient fitness increases Cooperation Altruism
Recipient fitness decreases Selfishness Spite
Why "altruistic" and "spiteful" behaviours are both difficult to reconcile with natural
Cooperation and selfishness are easy to reconcile w natural selection because the individual benefits. On
the other hand, altruism and spite are difficult to reconcile. Spite almost is non-existent in the animal
species because it reduces the fitness of everyone involved and selection is not favoured. Altruism (not
considering parental care); individuals may provide warning calls/ protection for non-offspring (eg.
meerkats, ground squirrels); benefits fitness of recipient, but puts the individual actor at risk.
How can traits spread if they reduce the actor’s lifetime reproductive success? This means sacrificing
individual fitness for the good of the group. But selection will not favour this behaviour because it just
looks at the individual.
How kin selection theory explains the