Hamilton's Rule
Altruism Evolves
Hamilton's rule is a mathematical formula that predicts when altruism will evolve in a population. It states that altruism will evolve when the cost to the actor is less than the benefit to the recipient, multiplied by the probability that the recipient carries a copy of the gene for altruism. This rule has been applied to various fields, including evolutionary psychology, to understand the evolution of cooperation and altruism.
- Altruism evolves when the cost to the actor is less than the benefit to the recipient, multiplied by the probability that the recipient carries a copy of the gene for altruism.
- The degree of genetic relatedness between individuals affects the evolution of altruism.
- The cost and benefit of altruism are measured in reproductive currencies.
- Calculate the cost to the actorDetermine the cost to the individual performing the altruistic act, in terms of reproductive currency.Pro tipConsider the potential risks and benefits to the actor's own fitness.WarningBe careful not to overestimate the cost, as this may lead to incorrect predictions.
- Calculate the benefit to the recipientDetermine the benefit to the individual receiving the altruistic act, in terms of reproductive currency.Pro tipConsider the potential benefits to the recipient's fitness, such as increased survival or reproductive success.WarningBe careful not to overestimate the benefit, as this may lead to incorrect predictions.
- Calculate the probability of genetic relatednessDetermine the probability that the recipient carries a copy of the gene for altruism, based on the degree of genetic relatedness between the actor and the recipient.Pro tipConsider the genetic relationship between the actor and the recipient, such as sibling, parent-offspring, or cousin.WarningBe careful not to overestimate the probability, as this may lead to incorrect predictions.
- Apply Hamilton's ruleUse the calculated values to determine whether altruism will evolve, according to Hamilton's rule.Pro tipConsider the overall fitness consequences of the altruistic act, including the potential benefits and costs to both the actor and the recipient.WarningBe careful not to misapply the rule, as this may lead to incorrect predictions.
Ground squirrels have been observed to engage in altruistic behavior, such as warning calls, to protect their kin from predators.
Humans have been observed to engage in altruistic behavior, such as donating to charity or volunteering, to help their kin and non-kin.
Hamilton's rule was first proposed by William D. Hamilton in 1964, as a way to explain the evolution of altruism in social insects. Since then, it has been widely applied and tested in various fields, including evolutionary biology, psychology, and anthropology.