scholarly journals Belief in an Afterlife Influences Altruistic Helping Intentions in Alignment With Adaptive Tendencies

2021 ◽  
Vol 19 (2) ◽  
pp. 147470492110117
Author(s):  
Saeed Rezvani Nejad ◽  
Ahmad Borjali ◽  
Mahdi Khanjani ◽  
Daniel J. Kruger
Keyword(s):  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Empirical Support ◽  
Reciprocal Altruism ◽  
Reproductive Value ◽  
Altruistic Behavior ◽  
Psychological Mechanisms ◽  
Inclusive Fitness Theory ◽  
Fitness Consequences ◽  
Reproductive Consequences

Evolutionary definitions of altruism are only concerned with reproductive consequences and not motives or other psychological mechanisms, making them ideal for generalization to all forms of organisms. Hamilton’s inclusive fitness theory explains altruistic behavior toward genetic relatives and has generated extensive empirical support. Trivers’ theory of reciprocal altruism helps explain patterns of helping among non-kin, and other research has demonstrated that human helping intentions follow fitness consequences from age-based reproductive value on altruism. The current study examines a novel psychological factor, belief in the afterlife, which may influence altruistic helping intentions. Belief in the afterlife was incorporated into a previous study design assessing the effects of a target’s genetic relatedness and age-based reproductive value. The influences of inclusive fitness and target age were reproduced in a non-Western sample of participants ( N = 300) in Iran. Belief in the afterlife predicted the overall confidence of risking one’s life to save another across all targets, and also moderated the effects of genetic relatedness and target age. Rather than promoting altruism equitably or advantaging those favored by adaptive tendencies, higher belief in an afterlife aligned with these tendencies in promoting further favoritism toward close kin and younger targets with higher reproductive value.

Evidence, Other Approaches, and Further Topics

2015 ◽  
Author(s):  
James A.R. Marshall
Keyword(s):  
Social Evolution ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Replicator Dynamics ◽  
Empirical Support ◽  
Natural World ◽  
Price Equation ◽  
Evolution Theory ◽  
Inclusive Fitness Theory ◽  
The Many

This book has examined the genesis, the logic, and the generality of social evolution theory. In particular, it has presented evolutionary explanations of the many social behaviors we observe in the natural world by showing that William D. Hamilton's inclusive fitness theory provides the necessary generalization of classical Darwin–Wallace–Fisher fitness. This concluding chapter discusses the limitations of the analyses presented in this book and assesses the empirical support for inclusive fitness theory, focusing on microbial altruism, help in cooperative breeders, reproductive restraint in eusocial species, and the evolution of eusociality and cooperative breeding. It also considers more advanced topics in social evolution theory, including sex allocation, genetic kin recognition, spite, and the evolution of organismality. Finally, it reviews theoretical approaches to studying social evolution other than replicator dynamics and the Price equation, such as population genetics, class-structured populations, and maximization approaches.

scholarly journals Male relatedness and familiarity are required to modulate male-induced harm to females in Drosophila

2017 ◽  
Vol 284 (1860) ◽  
pp. 20170441 ◽  
Author(s):  
Sally Le Page ◽  
Irem Sepil ◽  
Ewan Flintham ◽  
Tommaso Pizzari ◽  
Pau Carazo ◽  
...  
Keyword(s):  
Potential Role ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Female Reproduction ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Indirect Fitness ◽  
Female Lifespan

Males compete over mating and fertilization, and often harm females in the process. Inclusive fitness theory predicts that increasing relatedness within groups of males may relax competition and discourage male harm of females as males gain indirect benefits. Recent studies in Drosophila melanogaster are consistent with these predictions, and have found that within-group male relatedness increases female fitness, though others have found no effects. Importantly, these studies did not fully disentangle male genetic relatedness from larval familiarity, so the extent to which modulation of harm to females is explained by male familiarity remains unclear. Here we performed a fully factorial design, isolating the effects of male relatedness and larval familiarity on female harm. While we found no differences in male courtship or aggression, there was a significant interaction between male genetic relatedness and familiarity on female reproduction and survival. Relatedness among males increased female lifespan, reproductive lifespan and overall reproductive success, but only when males were familiar. By showing that both male relatedness and larval familiarity are required to modulate female harm, these findings reconcile previous studies, shedding light on the potential role of indirect fitness effects on sexual conflict and the mechanisms underpinning kin recognition in fly populations.

scholarly journals Do Relatives With Greater Reproductive Potential Get Help First?: A Test of the Inclusive Fitness Explanation of Kin Altruism

2019 ◽  
Vol 17 (3) ◽  
pp. 147470491986709
Author(s):  
Jordan Schriver ◽  
W.Q. Elaine Perunovic ◽  
Kyle Brymer ◽  
Timothy Hachey
Keyword(s):  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Reproductive Potential ◽  
Causal Effects ◽  
Emotional Closeness ◽  
Child Study ◽  
Inclusive Fitness Theory

According to inclusive fitness theory, people are more willing to help those they are genetically related to because relatives share a kin altruism gene and are able to pass it along. We tested this theory by examining the effect of reproductive potential on altruism. Participants read hypothetical scenarios and chose between cousins (Studies 1 and 2) and cousins and friends (Study 3) to help with mundane chores or a life-or-death rescue. In life-or-death situations, participants were more willing to help a cousin preparing to conceive rather than adopt a child (Study 1) and a cousin with high rather than low chance of reproducing (Studies 2 and 3). Patterns in the mundane condition were less consistent. Emotional closeness also contributed to helping intentions (Studies 1 and 2). By experimentally manipulating reproductive potential while controlling for genetic relatedness and emotional closeness, we provide a demonstration of the direct causal effects of reproductive potential on helping intentions, supporting the inclusive fitness explanation of kin altruism.

What Is Fitness?

2015 ◽  
Author(s):  
James A.R. Marshall
Keyword(s):  
Reproductive Success ◽  
Inclusive Fitness ◽  
Structured Populations ◽  
Reproductive Value ◽  
Costs And Benefits ◽  
Risk Of Death ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Definition Of ◽  
Evolutionary Fitness

This chapter considers the problem of correctly defining fitness costs and benefits in inclusive fitness theory, when competition occurs between offspring who are relatives. It reviews the definition of evolutionary fitness and shows how its misinterpretation explains many previous misunderstandings as to whether inclusive fitness theory always makes accurate predictions. The chapter begins with a discussion of Haldane's dilemma, which can be formalized with fitness equations that show that the risk of death can make fitness effects all-or-nothing. It then examines how inclusive fitness models can be constructed to deal with reproductive value and class-structured populations. It also shows how costs and benefits can be expressed as payoffs that are proportional to reproductive success, as changes in production of offspring, or as changes in evolutionary fitness. Finally, it presents examples that illustrate when fitness, payoffs, and fecundity are different, and how inclusive fitness analyses can be performed properly in such situations.

scholarly journals The sociobiology of sex: inclusive fitness consequences of inter-sexual interactions

2012 ◽  
Vol 367 (1600) ◽  
pp. 2314-2323 ◽  
Author(s):  
Tommaso Pizzari ◽  
Andy Gardner
Keyword(s):  
Social Interactions ◽  
Sexual Conflict ◽  
Indirect Effects ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Fitness Consequences ◽  
Indirect Fitness ◽  
Population Viscosity

The diversity of social interactions between sexual partners has long captivated biologists, and its evolution has been interpreted largely in terms of ‘direct fitness’ pay-offs to partners and their descendants. Inter-sexual interactions also have ‘indirect effects’ by affecting the fitness of relatives, with important consequences for inclusive fitness. However, inclusive fitness arguments have received limited consideration in this context, and definitions of ‘direct’ and ‘indirect’ fitness effects in this field are often inconsistent with those of inclusive fitness theory. Here, we use a sociobiology approach based on inclusive fitness theory to distinguish between direct and indirect fitness effects. We first consider direct effects: we review how competition leads to sexual conflict, and discuss the conditions under which repression of competition fosters sexual mutualism. We then clarify indirect effects, and show that greenbeard effects, kin recognition and population viscosity can all lead to episodes of indirect selection on sexual interactions creating potential for sexual altruism and spite. We argue that the integration of direct and indirect fitness effects within a sociobiology approach enables us to consider a more diverse spectrum of evolutionary outcomes of sexual interactions, and may help resolving current debates over sexual selection and sexual conflict.

PSYCHOLOGICAL ASPECTS OF ADAPTATIONS FOR KIN DIRECTED ALTRUISTIC HELPING BEHAVIORS

2001 ◽  
Vol 29 (4) ◽  
pp. 323-330 ◽  
Author(s):  
Daniel J. Kruger
Keyword(s):  
Reproductive Success ◽  
Genetic Similarity ◽  
Inclusive Fitness ◽  
Close Relation ◽  
Psychological Aspects ◽  
Questionnaire Study ◽  
Altruistic Behavior ◽  
Material Wealth ◽  
Psychological Component ◽  
Inclusive Fitness Theory

This questionnaire study sheds light on the psychological component of kin selecting tendencies predicted by Hamilton's (1964b) inclusive fitness theory of discriminatory altruistic behavior based on genetic similarity. Participants rated donations of assistance aiding survival and material wealth as more rational and ethical when these actions were performed for closer relatives. Participants also felt a greater obligation to perform these acts for a close relation. A comparison condition where assistance was unlikely to affect survival or reproductive success did not exhibit these tendencies.

scholarly journals Do Somatic Cells Really Sacrifice Themselves? Why an Appeal to Coercion May be a Helpful Strategy in Explaining the Evolution of Multicellularity

2021 ◽  
Author(s):  
Adrian Stencel ◽  
Javier Suárez
Keyword(s):  
Present Article ◽  
Evolutionary Biology ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Somatic Cells ◽  
Next Generation ◽  
Inclusive Fitness Theory ◽  
Germline Cells ◽  
Multicellular Organisms

AbstractAn understanding of the factors behind the evolution of multicellularity is one of today’s frontiers in evolutionary biology. This is because multicellular organisms are made of one subset of cells with the capacity to transmit genes to the next generation (germline cells) and another subset responsible for maintaining the functionality of the organism, but incapable of transmitting genes to the next generation (somatic cells). The question arises: why do somatic cells sacrifice their lives for the sake of germline cells? How is germ/soma separation maintained? One conventional answer refers to inclusive fitness theory, according to which somatic cells sacrifice themselves altruistically, because in so doing they enhance the transmission of their genes by virtue of their genetic relatedness to germline cells. In the present article we will argue that this explanation ignores the key role of policing mechanisms in maintaining the germ/soma divide. Based on the pervasiveness of the latter, we argue that the role of altruistic mechanisms in the evolution of multicellularity is limited and that our understanding of this evolution must be enriched through the consideration of coercion mechanisms.

Social Evolution, Hamilton’s Rule, and Inclusive Fitness

2018 ◽  
Author(s):  
Samir Okasha
Keyword(s):  
Social Behaviour ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Popular Approach ◽  
Hamilton’S Rule ◽  
Inclusive Fitness Theory ◽  
The Social ◽  
Social Encounters ◽  
The Individual ◽  
Hamilton's Rule

Inclusive fitness theory, originally due to W. D. Hamilton, is a popular approach to the study of social evolution, but shrouded in controversy. The theory contains two distinct aspects: Hamilton’s rule (rB > C); and the idea that individuals will behave as if trying to maximize their inclusive fitness in social encounters. These two aspects of the theory are logically separable but often run together. A generalized version of Hamilton’s rule can be formulated that is always true, though whether it is causally meaningful is debatable. However, the individual maximization claim only holds true if the payoffs from the social encounter are additive. The notion that inclusive fitness is the ‘goal’ of individuals’ social behaviour is less robust than some of its advocates acknowledge.

scholarly journals Inclusive Fitness Theory from Darwin to Hamilton

Genetics ◽  
2007 ◽  
Vol 176 (3) ◽  
pp. 1375-1380
Author(s):  
Lee Alan Dugatkin
Keyword(s):  
Inclusive Fitness ◽  
Inclusive Fitness Theory
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