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Recent years have seen a renewed debate over the importance of groupselection, especially as it relates to the evolution of altruism. Onefeature of this debate has been disagreement over which kinds ofprocesses should be described in terms of selection at multiple levels,within and between groups. Adapting some earlier discussions, we presenta mathematical framework that can be used to explore the exactrelationships between evolutionary models that do, and those that donot, explicitly recognize biological groups as fitness-bearing entities.We show a fundamental set (...) of mathematical equivalences between these twokinds of models, one of which applies a form of multi-level selectiontheory and the other being a form of ``individualism.'' However, we alsoargue that each type of model can have heuristic advantages over theother. Indeed, it can be positively useful to engage in a kind ofback-and-forth switching between two different perspectives on theevolutionary role of groups. So the position we defend is a``gestalt-switching pluralism.''. (shrink)

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Altruism is generally understood to be behavior that benefits others at a personal cost to the behaving individual. However, within evolutionary biology, different authors have interpreted the concept of altruism differently, leading to dissimilar predictions about the evolution of altruistic behavior. Generally, different interpretations diverge on which party receives the benefit from altruism and on how the cost of altruism is assessed. Using a simple trait-group framework, we delineate the assumptions underlying different interpretations and show how they relate to one (...) another. We feel that a thorough examination of the connections between interpretations not only reveals why different authors have arrived at disparate conclusions about altruism, but also illuminates the conditions that are likely to favor the evolution of altruism. (shrink)

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Formal methods developed for modeling levels of selection problems have recently been applied to the investigation of major evolutionary transitions. We discuss two new tools of this kind. First, the ‘near-variant test’ can be used to compare the causal adequacy of predictively equivalent representations. Second, ‘state-variable gestalt-switching’ can be used to gain a useful dual perspective on evolutionary processes that involve both higher and lower level populations.

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Wright’s “adaptive landscape” has been influential in evolutionary thinking but controversial, especially because the landscape that organisms encounter is altered by the evolutionary process itsel...

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The emergence of individuality during the evolutionary transition from single cells to multicellularity poses a range of problems. A key issue is how variation in lower‐level individuals generates a corporate (collective) entity with Darwinian characteristics. Of central importance to this process is the evolution of a means of collective reproduction, however, the evolution of a means of collective reproduction is not a trivial issue, requiring careful consideration of mechanistic details. Calling upon observations from experiments, we draw attention to proto‐life cycles (...) that emerge via unconventional routes and that transition, in single steps, individuality to higher levels. One such life cycle arises from conflicts among levels of selection and invokes cheats as a primitive germ line: it lays the foundation for collective reproduction, the basis of a self‐policing system, the selective environment for the emergence of development, and hints at a plausible origin for a soma/germ line distinction. (shrink)

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Despite the fact that animal behavior involves a particularly powerful form of niche construction, few researchers have considered how the environmental impact of behavior may feed back to influence the evolution of the cognitive underpinnings of behavior. I explore a model that explicitly incorporates niche construction while tracking cognitive evolution. Agents and their stimuli are modeled as coevolving populations. The agents are born with “weights” attached to behaviors in a repertoire. Further, these agents are able to change these weights based (...) on previous success and an inherited learning parameter. Both the agent and the stimulus receive payoffs through a behavioral interaction . The behaving agent exhibits niche construction through its effects on stimuli , which can feed back to influence the value of different cognitive strategies. Here I focus on two forms of niche construction: the stimulus and responding agent have common interests and the stimulus and agent have dissimilar interests . The form of niche construction qualitatively affects cognitive evolution . Given a mutualism between the stimulus and responding agent, rapid learning and “fixed” behavioral distributions evolve. Given an antagonism between the stimulus and agent, slower learning and “flexible” behavioral distributions evolve. I discuss these results in light of findings from the fields of ethology, psychology, and evolutionary ecology. (shrink)

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Journal of Political Philosophy, EarlyView.

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A model of “ephemeral” population structure is presented that applies not only to biological systems in which discrete groups form but also to networks without group boundaries. The evolution of altruistic behaviors is discussed. Nonrandom interaction and nonlinear fitness structures are modeled; together, these factors can produce stable polymorphisms of altruistic and selfish types, as well as bistability. Empirical applications of the model may be found in microbes, marine invertebrates, annual plants, and other organisms.

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