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David Sloan Wilson - One of the best experts on this subject based on the ideXlab platform.
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Population viscosity and the evolution of Altruism
Journal of Theoretical Biology, 2000Co-Authors: Joshua Mitteldorf, David Sloan WilsonAbstract:The term population viscosity refers to limited dispersal, which increases the genetic relatedness of neighbors. This effect both supports the evolution of Altruism by focusing the altruists' gifts on relatives of the altruist, and also limits the extent to which Altruism may emerge by exposing clusters of altruists to stiffer local competition. Previous analyses have emphasized the way in which these two effects can cancel, limiting the viability of Altruism. These papers were based on models in which total population density was held fixed. We present here a class of models in which population density is permitted to fluctuate, so that patches of altruists are supported at a higher density than patches of non-altruists. Under these conditions, population viscosity can support the selection of both weak and strong Altruism. (C) 2000 Academic Press.
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Altruism, tit for tat and ‘outlaw’ genes
Evolutionary Ecology, 1994Co-Authors: Lee Alan Dugatkin, David Sloan Wilson, Livingston Farrand, Richard T. WilkensAbstract:In a prior study we combined game theory and inclusive fitness models to examine whether the guarded Altruism that can evolve among non-relatives (tit for tat, TFT) might also evolve among close relatives, supplanting unconditional Altruism. In most cases, TFT replaced unconditional Altruism in family-structured models. Even when TFT is selected at a single locus, however, by withholding Altruism from non-reciprocating relatives it may qualify as an ‘outlaw’ from the standpoint of modifier genes at other loci. Here we examine this possibility with a series of haploid, two-locus models in which a modifier gene transforms TFT into unconditional Altruism. The modifier allele spreads to fixation whenever Hamilton's Rule is satisfied, resulting in an unconditional altruist replacing the TFT strategy. As such, TFT may be regarded as an outlaw vulnerable to suppression by alleles at other loci.
Lee Alan Dugatkin - One of the best experts on this subject based on the ideXlab platform.
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Altruism, tit for tat and ‘outlaw’ genes
Evolutionary Ecology, 1994Co-Authors: Lee Alan Dugatkin, David Sloan Wilson, Livingston Farrand, Richard T. WilkensAbstract:In a prior study we combined game theory and inclusive fitness models to examine whether the guarded Altruism that can evolve among non-relatives (tit for tat, TFT) might also evolve among close relatives, supplanting unconditional Altruism. In most cases, TFT replaced unconditional Altruism in family-structured models. Even when TFT is selected at a single locus, however, by withholding Altruism from non-reciprocating relatives it may qualify as an ‘outlaw’ from the standpoint of modifier genes at other loci. Here we examine this possibility with a series of haploid, two-locus models in which a modifier gene transforms TFT into unconditional Altruism. The modifier allele spreads to fixation whenever Hamilton's Rule is satisfied, resulting in an unconditional altruist replacing the TFT strategy. As such, TFT may be regarded as an outlaw vulnerable to suppression by alleles at other loci.
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Nepotism vs Tit-For-Tat, or, why should you be nice to your rotten brother?
Evolutionary Ecology, 1991Co-Authors: D. S. Wilson, Lee Alan DugatkinAbstract:It is well known that interactions among relatives facilitate the evolution of altruistic behaviours. Game theoretic models show, however, that guarded Altruism (such as Tit-For-Tat) can evolve among non-relatives when individuals interact many times and ‘cheating’ behaviours can be punished. Strangely, no one has yet asked whether the guarded Altruism that evolves among non-relatives might also evolve among close relatives, supplanting unconditional altriusm. We present a series of one-locus sexual haploid models in which Tit-For-Tat, unconditional altruists and selfish individuals interact in groups of full siblings. Tit-For-Tat frequently (but not always) replaced unguarded Altruism, in which case the strategic ‘rules’ for interacting with kin vs non-kin are identical. Even when Tit-For-Tat is selected at a single locus, however, by withholding Altruism for non-reciprocating relatives it may qualify as an ‘outlaw’ from the standpoint of modifier genes at other loci.
Joshua Mitteldorf - One of the best experts on this subject based on the ideXlab platform.
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Population viscosity and the evolution of Altruism
Journal of Theoretical Biology, 2000Co-Authors: Joshua Mitteldorf, David Sloan WilsonAbstract:The term population viscosity refers to limited dispersal, which increases the genetic relatedness of neighbors. This effect both supports the evolution of Altruism by focusing the altruists' gifts on relatives of the altruist, and also limits the extent to which Altruism may emerge by exposing clusters of altruists to stiffer local competition. Previous analyses have emphasized the way in which these two effects can cancel, limiting the viability of Altruism. These papers were based on models in which total population density was held fixed. We present here a class of models in which population density is permitted to fluctuate, so that patches of altruists are supported at a higher density than patches of non-altruists. Under these conditions, population viscosity can support the selection of both weak and strong Altruism. (C) 2000 Academic Press.
James Andreoni - One of the best experts on this subject based on the ideXlab platform.
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Altruism in Experiments
Behavioural and Experimental Economics, 2020Co-Authors: James Andreoni, William T. Harbaugh, Lise VesterlundAbstract:Unlike experiments on markets or mechanisms, experiments on Altruism are about an individual motive or intention. This raises serious obstacles for research. How do we define an altruistic act, and how do we know Altruism when we see it?
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impure Altruism and donations to public goods a theory of warm glow giving
The Economic Journal, 1990Co-Authors: James AndreoniAbstract:When people make donations to privately provided public goods, such as charity, there may be many factors influencing their decision other than Altruism. Social pressure, guilt, sympathy, or simply a desire for a "warm glow" may all be important. This paper considers such impure Altruism formally and develops a wide set of implications. In particular, this paper discusses the invariance proposition of public goods, solves for the sufficient conditions for neutrality to hold, examines the optimal tax treatment of charitable giving, and calibrates the model based on econometric studies in order to consider policy experiments. Impure Altruism is shown to be more consistent with observed patterns of giving than the conventional pure Altruism approach, and to have policy implications that may differ widely from those of the conventional models. Copyright 1990 by Royal Economic Society.
D. S. Wilson - One of the best experts on this subject based on the ideXlab platform.
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Nepotism vs Tit-For-Tat, or, why should you be nice to your rotten brother?
Evolutionary Ecology, 1991Co-Authors: D. S. Wilson, Lee Alan DugatkinAbstract:It is well known that interactions among relatives facilitate the evolution of altruistic behaviours. Game theoretic models show, however, that guarded Altruism (such as Tit-For-Tat) can evolve among non-relatives when individuals interact many times and ‘cheating’ behaviours can be punished. Strangely, no one has yet asked whether the guarded Altruism that evolves among non-relatives might also evolve among close relatives, supplanting unconditional altriusm. We present a series of one-locus sexual haploid models in which Tit-For-Tat, unconditional altruists and selfish individuals interact in groups of full siblings. Tit-For-Tat frequently (but not always) replaced unguarded Altruism, in which case the strategic ‘rules’ for interacting with kin vs non-kin are identical. Even when Tit-For-Tat is selected at a single locus, however, by withholding Altruism for non-reciprocating relatives it may qualify as an ‘outlaw’ from the standpoint of modifier genes at other loci.