Social Discounting of Monetary Rewards

2011 ◽  
Vol 16 (3) ◽  
pp. 220-226 ◽  
Author(s):  
Paweł Ostaszewski ◽  
Jerzy Tomasz Osiński
Keyword(s):  
Evolutionary Theory ◽  
Social Relationship ◽  
Inclusive Fitness ◽  
Monetary Rewards ◽  
The People ◽  
Inclusive Fitness Theory ◽  
Social Discounting ◽  
Subjective Value ◽  
Reward Amount

The purpose of the study was to test hypotheses regarding a form of social discounting in which the subjective value of a reward decreases as a function of the number of people it is shared with. Based on evolutionary theory, individuals’ social discounting rates were expected to depend on both reward amount and the type of relationship with the people with whom the reward would be shared. As predicted, smaller amounts were discounted less steeply than larger ones, and social discounting was steepest when sharing with strangers and shallowest when sharing with family. The effect of the type of social relationship is consistent with Hamilton’s inclusive fitness theory. The shallower discounting of smaller rewards may be adaptive when resources are limited; alternatively, this finding may be due to the degree of disappointment that is anticipated if the reward is unfairly shared, assuming that the disappointment increases with the size of the reward being withheld by the group.

scholarly journals There is no fitness but fitness, and the lineage is its bearer

2016 ◽  
Vol 371 (1687) ◽  
pp. 20150085 ◽  
Author(s):  
Erol Akçay ◽  
Jeremy Van Cleve
Keyword(s):  
Evolutionary Theory ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Inclusive Fitness Theory ◽  
Darwinian Fitness ◽  
Accurate Picture ◽  
Evolutionary Success ◽  
Social Environmental ◽  
The Individual ◽  
Modern Evolutionary Theory

Inclusive fitness has been the cornerstone of social evolution theory for more than a half-century and has matured as a mathematical theory in the past 20 years. Yet surprisingly for a theory so central to an entire field, some of its connections to evolutionary theory more broadly remain contentious or underappreciated. In this paper, we aim to emphasize the connection between inclusive fitness and modern evolutionary theory through the following fact: inclusive fitness is simply classical Darwinian fitness, averaged over social, environmental and demographic states that members of a gene lineage experience. Therefore, inclusive fitness is neither a generalization of classical fitness, nor does it belong exclusively to the individual. Rather, the lineage perspective emphasizes that evolutionary success is determined by the effect of selection on all biological and environmental contexts that a lineage may experience. We argue that this understanding of inclusive fitness based on gene lineages provides the most illuminating and accurate picture and avoids pitfalls in interpretation and empirical applications of inclusive fitness theory.

DISCOUNTING OF SHARED REWARDS IN PIGEONS

2019 ◽  
Vol 45 (2) ◽  
pp. 454-467
Author(s):  
Tetsuo Yamaguchi ◽  
Daisuke Saeki ◽  
Kenichiro Taniguchi ◽  
Masato Ito
Keyword(s):  
Food Sharing ◽  
Mathematical Function ◽  
Indifference Point ◽  
Exponential Functions ◽  
Monetary Rewards ◽  
Social Discounting ◽  
Subjective Value ◽  
The Social ◽  
Access To Food ◽  
The Given

Pigeons chose between shared (communal) and unshared patches. In the shared patch, the pigeon would share 14 food pellets with zero to seven other pigeons. In the unshared patch, the pigeon had access to food pellets by itself, in an amount that depended on the given trial. The number of food pellets in the unshared patch was increased or decreased depending on the pigeon’s choices, and the indifference point (the subjective value of the shared reward), here the pigeon chose the shared and unshared patches equally often, was reached. The subjective value of the shared rewards decreased systematically as the number of pigeons sharing the rewards increased. The discounting of the shared rewards was well- described using both hyperbolic and exponential functions. The results suggest that food sharing is a discounting factor, and the mathematical function that describes the social discounting of hypothetical monetary rewards in humans described social discounting in pigeons receiving real rewards.

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 No consistent startle modulation by reward

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Iris Schutte ◽  
Johanna M. P. Baas ◽  
Ivo Heitland ◽  
J. Leon Kenemans
Keyword(s):  
Startle Reflex ◽  
Task Engagement ◽  
Future Experiment ◽  
Reflex Modulation ◽  
Monetary Rewards ◽  
Potential Gain ◽  
Subjective Value ◽  
Experimental Parameters ◽  
Startle Modulation ◽  
Aversive Motivation

AbstractPrevious studies have not clearly demonstrated whether motivational tendencies during reward feedback are mainly characterized by appetitive responses to a gain or mainly by aversive consequences of reward omission. In the current study this issue was addressed employing a passive head or tails game and using the startle reflex as an index of the appetitive-aversive continuum. A second aim of the current study was to use startle-reflex modulation as a means to compare the subjective value of monetary rewards of varying magnitude. Startle responses after receiving feedback that a potential reward was won or not won were compared with a baseline condition without a potential gain. Furthermore, startle responses during anticipation of no versus potential gain were compared. Consistent with previous studies, startle-reflex magnitudes were significantly potentiated when participants anticipated a reward compared to no reward, which may reflect anticipatory arousal. Specifically for the largest reward (20-cents) startle magnitudes were potentiated when a reward was at stake but not won, compared to a neutral baseline without potential gain. In contrast, startle was not inhibited relative to baseline when a reward was won. This suggests that startle modulation during feedback is better characterized in terms of potentiation when missing out on reward rather than in terms of inhibition as a result of winning. However, neither of these effects were replicated in a more targeted second experiment. The discrepancy between these experiments may be due to differences in motivation to obtain rewards or differences in task engagement. From these experiments it may be concluded that the nature of the processing of reward feedback and reward cues is very sensitive to experimental parameters and settings. These studies show how apparently modest changes in these parameters and settings may lead to quite different modulations of appetitive/aversive motivation. A future experiment may shed more light on the question whether startle-reflex modulation after feedback is indeed mainly characterized by the aversive consequences of reward omission for relatively large rewards.

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

scholarly journals War and peace: social interactions in infections

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130365 ◽  
Author(s):  
Helen C. Leggett ◽  
Sam P. Brown ◽  
Sarah E. Reece
Keyword(s):  
Species Interactions ◽  
Disease Ecology ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Experimental Tests ◽  
Microbial Pathogens ◽  
Emergent Properties ◽  
Social Strategies ◽  
Inclusive Fitness Theory ◽  
Social Behaviours

One of the most striking facts about parasites and microbial pathogens that has emerged in the fields of social evolution and disease ecology in the past few decades is that these simple organisms have complex social lives, indulging in a variety of cooperative, communicative and coordinated behaviours. These organisms have provided elegant experimental tests of the importance of relatedness, kin discrimination, cooperation and competition, in driving the evolution of social strategies. Here, we briefly review the social behaviours of parasites and microbial pathogens, including their contributions to virulence, and outline how inclusive fitness theory has helped to explain their evolution. We then take a mechanistically inspired ‘bottom-up’ approach, discussing how key aspects of the ways in which parasites and pathogens exploit hosts, namely public goods, mobile elements, phenotypic plasticity, spatial structure and multi-species interactions, contribute to the emergent properties of virulence and transmission. We argue that unravelling the complexities of within-host ecology is interesting in its own right, and also needs to be better incorporated into theoretical evolution studies if social behaviours are to be understood and used to control the spread and severity of infectious diseases.

Care at home for people with dementia: as in a total institution?

2006 ◽  
Vol 27 (1) ◽  
pp. 3-24 ◽  
Author(s):  
JANET ASKHAM ◽  
KATE BRIGGS ◽  
IAN NORMAN ◽  
SALLY REDFERN
Keyword(s):  
Intimate Relationships ◽  
Social Relationship ◽  
Intimate Relationship ◽  
Total Institution ◽  
Home Life ◽  
The People ◽  
People With Dementia ◽  
Custodial Care ◽  
Care At Home ◽  
At Home

This article examines three kinds of social relationship likely to be present when people with dementia are cared for at home by relatives or friends: custodial care, an intimate relationship, and home-life. Using Goffman's three defining aspects of custodial care – routinisation, surveillance and mortification of the self – the paper examines whether these characterised the care of people with dementia at home and, if so, whether they conflicted with the intimate relationship and with home-life. The study involved sustained observations and interviews with 20 people with dementia and their carers in and around London, and qualitative analysis of the data. It was found that all three aspects of custodial care were present although not fully realised, and that they led to difficulties, many of which were associated with the concurrent pursuit of an intimate relationship and home-life. In all cases, daily life was routinised partly to help accomplish care tasks but was found monotonous, while surveillance was usual but restrictive, and prevented both the carers and those with dementia from doing things that they wished to do. Those with dementia were distressed by the denial of their former identities, such as car-driver or home-maker, and by being treated like children. Both the carers and the people with dementia had various ways of balancing custodial care, their intimate relationships and home-life, such as combining routines with other activities, evading surveillance or carrying it out by indirect means, and there were many attempts to maintain some semblance of former identities.

scholarly journals OPPOSITION TO INBREEDING AMONG CLOSE KIN

2018 ◽  
Author(s):  
Jan Antfolk ◽  
Debra Lieberman ◽  
Christopher Harju ◽  
Anna Albrecht ◽  
Andreas Mokros ◽  
...  
Keyword(s):  
Inclusive Fitness ◽  
Large Population ◽  
Self Regulation ◽  
Family Members ◽  
Indirect Costs ◽  
Population Based ◽  
Fitness Costs ◽  
Inclusive Fitness Theory ◽  
The Difference ◽  
Close Relatives

Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene’s-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive-fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.

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 Testing the Kundera Hypothesis: Does Every Woman (But Not Every Man) Prefer Her Child to Her Mate?

2018 ◽  
Vol 16 (4) ◽  
pp. 147470491880886
Author(s):  
Carlos Hernández Blasi ◽  
Laura Mondéjar
Keyword(s):  
College Students ◽  
Inclusive Fitness ◽  
Milan Kundera ◽  
Men And Women ◽  
Car Crash ◽  
Inclusive Fitness Theory ◽  
Role Of Women

The context of a famous novel by Milan Kundera ( Immortality) suggests that when faced with a life-or-death situation, every woman would prefer to save her child than her husband, left hanging whether every man would do the same. We labeled this as the Kundera hypothesis, and the purpose of this study was to test it empirically as we believe it raises a thought-provoking question in evolutionary terms. Specifically, 197 college students (92 women) were presented a questionnaire where they had to make different decisions about four dilemmas about who to save (their mate or their offspring) in two hypothetical life-or-death situations: a home fire and a car crash. These dilemmas involved two different mate ages (a 25- or a 40-year-old mate) and two offspring ages (1- or a 6-year-old child). For comparative purposes, we also included complementary life-or-death dilemmas on both a sibling and an offspring, and a sibling and a cousin. The results generally supported the Kundera hypothesis: Although the majority of men and women made the decision to save their offspring instead of their mate, about 18% of men on average (unlike the 5% of women) consistently decided to save their mate across the four dilemmas in the two life-or-death situations. These data were interpreted with reference to Hamilton’s inclusive fitness theory, the preferential role of women as kin keepers, and the evolution of altruism toward friends and mates.

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