Kin Selection
Updated 2026-08-02
INTRODUCTION
English translation pending.
CORE DEFINITION
Developed by William Hamilton, kin selection explains altruistic behavior toward relatives through inclusive fitness: an individual can pass on copies of its genes either by reproducing or by helping those who share them. Hamilton's rule states that altruism spreads when rB exceeds C, where r is the coefficient of relatedness, B the benefit to the recipient, and C the cost to the actor. The framework explains sterile worker castes in social insects and much parental care. Key qualification: relatedness is only one channel for cooperation, since reciprocity sustains altruism among unrelated individuals.
SCAFFOLDING EFFECT
Reduce cognitive load
- Compute the ratio: weigh the benefit to the relative against your cost and the relatedness between you. - Predict behavior: expect stronger sacrifice where relatedness and benefit are both high. - Distinguish mechanisms: separate kinship-based cooperation from reciprocity among unrelated parties.
Anchor fast decisions
A gene that causes its carrier to help a relative can increase the number of copies of itself in the next generation, because the relative is likely to carry the same variant. Selection therefore acts on total transmission of genes rather than on individual survival alone. This makes sacrifice rational in evolutionary terms when the benefit multiplied by relatedness exceeds the cost.
MINIMUM ACTION
In progress 0/1Practice this model in one real situation:
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Source support: Explicit
- zh.wikipedia.orghttps://zh.wikipedia.org/wiki/%E8%A6%AA%E5%B1%AC%E9%81%B8%E6%93%87verified
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