- Altruist-dense groups(contrasted with defector-dense groups)
- Groups where most members are willing to help others and cooperate, even at a cost to themselves.
- Defector-dense groups(contrasted with altruist-dense groups)
- Groups where most members prioritize their own interests and don't cooperate or help others.
- Evolve (in evolutionary terms)(describing how altruism can spread)
- To become more common in a population over time because it helps survival or reproduction.
- Multilevel selection theory(the main theory being discussed)
- A scientific framework suggesting that evolution can happen at multiple levels—not just individual survival, but also how well groups compete against each other.
- Outcompete(describing how one type of group beats another)
- To be more successful than a rival group in surviving and reproducing, often causing the rival group to shrink or disappear.
- Sober & Wilson 1998(the researchers and publication year of the theory)
- Elliott Sober and David Sloan Wilson are philosophers and scientists who published influential work arguing that groups with more cooperative members can outcompete selfish groups, allowing altruism to spread through evolution.
- Within-group recipient identity(a factor the theory says doesn't matter for altruism to evolve)
- Whether altruistic individuals know who they're helping or what relationship they have with the people they help.
- altruism(Evolutionary game theory)
- Any behaviour by an organism that decreases its own expected fitness in a single interaction but increases that of the other interactor