The Relation between Kin and Multilevel Selection: An Approach Using Causal Graphs

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-termsThe Relation between Kin and Multi-level SelectionAn Approach Using Causal Graphs Samir OkashaAbstract Kin selection and multi-level selection are alternative approaches for studying the evolution of social behaviour, the relation between which has long been a source of controversy. Many recent theorists regard the two approaches as ultimately equivalent, on the grounds that gene frequency change can be correctly expressed using either. However this shows only that the two are predictively equivalent, not that they offer equally good causal representations of the evolutionary process. This paper articulates the notion of an 'adequate causal representation' using causal graphs, and then seeks to identify circumstances under which kin and multi-level selection do and do not satisfy the test of causal adequacy.

Some Criticism of the Contextual Approach, and a Few Proposals

“…5). (Though see Okasha (2015), who adopts a causal interpretation of neighborhood analysis, and also Glymour (2008a, b).) If researchers want to estimate the extent to which possession of trait z is a cause of individual fitness, and the extent to which the frequency of z in a group is a cause of individual fitness, then they should estimate the values of b 1 z ij and b 2 Z j , respectively.…”

Distinguishing Natural Selection from Other Evolutionary Processes in the Evolution of Altruism

“…Thus, throughout the article, when I refer to an actor and a recipient, I will consistently refer to two different individuals. Before going further, it should also be noted that among the different notions of altruism used in the literature (see Kerr et al 2004), two particular notions have been debated, namely weak altruism and strong altruism (Wilson 1980;Okasha 2006). A weakly altruistic behavior is a behavior that benefits everyone interacting with the actor and the recipient equally.…”

“…Under this latter approach, in populations structured in groups, although selfish individuals beat altruistic ones within groups, altruistic groups beat selfish ones (Wilson and Wilson 2007, p. 345), and thus altruism can evolve in the general population. Many consider the two approaches to be formally equivalent (Okasha 2006;West et al 2007;Wilson and Wilson 2007) but for group selectionists the multilevel approach represents the best causal structure of the phenomenon, while the kin selectionists disagree that the notion of trait-group substantially enlightens any aspect that would not be captured by the notion of kin selection (West et al 2007(West et al , 2008. This has led some to advocate for pluralism on this question (Dugatkin and Reeve 1994;Sterelny 1996;Kerr and Godfrey-Smith 2002).…”

“…For a recent discussion on the relation between multilevel selection and kin selection seeOkasha (2015).…”

Beyond Hamilton's rule

“…Four recent insightful papers (3-6) shed more light on the evolution of cooperation, kin selection, and the role of relatedness in the evolution of cooperation. They indicate that HR has no fundamental role unless interpreted in causal terms (3,6), tackle issues associated with the notion of inclusive fitness and the role of relatedness in general (4), and reveal that group selection cannot always be reduced to kin selection, and vice versa (5,6).…”