scholarly journals Strategic investment explains patterns of cooperation and cheating in a microbe

2018 ◽  
Vol 115 (21) ◽  
pp. E4823-E4832 ◽  
Author(s):  
Philip G. Madgwick ◽  
Balint Stewart ◽  
Laurence J. Belcher ◽  
Christopher R. L. Thompson ◽  
Jason B. Wolf
Keyword(s):  
Kin Selection ◽  
High Frequency ◽  
Spore Dispersal ◽  
Strategic Investment ◽  
Social Amoeba ◽  
Investment Game ◽  
Genotype Frequencies ◽  
The Social ◽  
Group Members ◽  
Natural Strains

Contributing to cooperation is typically costly, while its rewards are often available to all members of a social group. So why should individuals be willing to pay these costs, especially if they could cheat by exploiting the investments of others? Kin selection theory broadly predicts that individuals should invest more into cooperation if their relatedness to group members is high (assuming they can discriminate kin from nonkin). To better understand how relatedness affects cooperation, we derived the ‟Collective Investment” game, which provides quantitative predictions for patterns of strategic investment depending on the level of relatedness. We then tested these predictions by experimentally manipulating relatedness (genotype frequencies) in mixed cooperative aggregations of the social amoebaDictyostelium discoideum, which builds a stalk to facilitate spore dispersal. Measurements of stalk investment by natural strains correspond to the predicted patterns of relatedness-dependent strategic investment, wherein investment by a strain increases with its relatedness to the group. Furthermore, if overall group relatedness is relatively low (i.e., no strain is at high frequency in a group) strains face a scenario akin to the “Prisoner’s Dilemma” and suffer from insufficient collective investment. We find that strains employ relatedness-dependent segregation to avoid these pernicious conditions. These findings demonstrate that simple organisms likeD. discoideumare not restricted to being ‟cheaters” or ‟cooperators” but instead measure their relatedness to their group and strategically modulate their investment into cooperation accordingly. Consequently, all individuals will sometimes appear to cooperate and sometimes cheat due to the dynamics of strategic investing.

scholarly journals Cooperation and conflict in the social amoeba Dictyostelium discoideum

2019 ◽  
Vol 63 (8-9-10) ◽  
pp. 371-382
Author(s):  
James M. Medina ◽  
P.M. Shreenidhi ◽  
Tyler J. Larsen ◽  
David C. Queller ◽  
Joan E. Strassmann
Keyword(s):  
Dictyostelium Discoideum ◽  
Fruiting Body ◽  
Sexual Cycle ◽  
Evolution Of Cooperation ◽  
Bacterial Symbionts ◽  
Spore Dispersal ◽  
Social Amoeba ◽  
The Social ◽  
The Relationship ◽  
Insight Into

The social amoeba Dictyostelium discoideum has provided considerable insight into the evolution of cooperation and conflict. Under starvation, D. discoideum amoebas cooperate to form a fruiting body comprised of hardy spores atop a stalk. The stalk development is altruistic because stalk cells die to aid spore dispersal. The high relatedness of cells in fruiting bodies in nature implies that this altruism often benefits relatives. However, since the fruiting body forms through aggregation there is potential for non-relatives to join the aggregate and create conflict over spore and stalk fates. Cheating is common in chimeras of social amoebas, where one genotype often takes advantage of the other and makes more spores. This social conflict is a significant force in nature as indicated by rapid rates of adaptive evolution in genes involved in cheating and its resistance. However, cheating can be prevented by high relatedness, allorecognition via tgr genes, pleiotropy and evolved resistance. Future avenues for the study of cooperation and conflict in D. discoideum include the sexual cycle as well as the relationship between D. discoideum and its bacterial symbionts. D. discoideum’s tractability in the laboratory as well as its uncommon mode of aggregative multicellularity have established it as a promising model for future studies of cooperation and conflict.

scholarly journals Kin selection, not group augmentation, predicts helping in an obligate cooperatively breeding bird

2012 ◽  
Vol 279 (1743) ◽  
pp. 3861-3869 ◽  
Author(s):  
L. E. Browning ◽  
S. C. Patrick ◽  
L. A. Rollins ◽  
S. C. Griffith ◽  
A. F. Russell
Keyword(s):  
Cooperative Breeding ◽  
Social Group ◽  
Kin Selection ◽  
Convincing Evidence ◽  
Breeding Bird ◽  
Direct Benefits ◽  
The Social ◽  
Group Members ◽  
The Cost ◽  
Large Groups

Kin selection theory has been the central model for understanding the evolution of cooperative breeding, where non-breeders help bear the cost of rearing young. Recently, the dominance of this idea has been questioned; particularly in obligate cooperative breeders where breeding without help is uncommon and seldom successful. In such systems, the direct benefits gained through augmenting current group size have been hypothesized to provide a tractable alternative (or addition) to kin selection. However, clear empirical tests of the opposing predictions are lacking. Here, we provide convincing evidence to suggest that kin selection and not group augmentation accounts for decisions of whether, where and how often to help in an obligate cooperative breeder, the chestnut-crowned babbler ( Pomatostomus ruficeps ). We found no evidence that group members base helping decisions on the size of breeding units available in their social group, despite both correlational and experimental data showing substantial variation in the degree to which helpers affect productivity in units of different size. By contrast, 98 per cent of group members with kin present helped, 100 per cent directed their care towards the most related brood in the social group, and those rearing half/full-sibs helped approximately three times harder than those rearing less/non-related broods. We conclude that kin selection plays a central role in the maintenance of cooperative breeding in this species, despite the apparent importance of living in large groups.

Social attribution, correspondence bias, and the emergence of stereotypes *This research has been completed in partial requirement of a doctoral dissertation of the first author under the supervision of the second author. We wish to thank the members of the social psychology division at the University of Louvain at Louvain-la-Neuve, especially Steve Rocher and Emanuele Castano for their insightful comments on preliminary drafts. This paper has been enriched by feedbacks received from Russell Spears, Roos Vonk, Margit Oswald, and anonymous reviewers. Many thanks to Philippe Kemp and Christophe Remy for their assistance in running the study, and to the students who volunteered to appear on the video. This research has been presented at the Social Cognition workshop of the Kurt Lewin Institute, workshop held at the Free University of Amsterdam in April 1998: we want to thank participants of this workshop and especially Gün Semin for their useful feedback. Completion of this study benefited from a research grant from the Belgian National Fund for Scientific Research to the first author.

1999 ◽  
Vol 58 (4) ◽  
pp. 233-240 ◽  
Author(s):  
Anouk Rogier ◽  
Vincent Yzerbyt
Keyword(s):  
Correspondence Bias ◽  
Social Attribution ◽  
The Social ◽  
Dispositional Attributions ◽  
Kurt Lewin ◽  
Group Members ◽  
Group Target ◽  
The University ◽  
Institute Workshop ◽  
Research Grant

Yzerbyt, Rogier and Fiske (1998) argued that perceivers confronted with a group high in entitativity (i.e., a group perceived as an entity, a tight-knit group) more readily call upon an underlying essence to explain people's behavior than perceivers confronted with an aggregate. Their study showed that group entitativity promoted dispositional attributions for the behavior of group members. Moreover, stereotypes emerged when people faced entitative groups. In this study, we replicate and extend these results by providing further evidence that the process of social attribution is responsible for the emergence of stereotypes. We use the attitude attribution paradigm ( Jones & Harris, 1967 ) and show that the correspondence bias is stronger for an entitative group target than for an aggregate. Besides, several dependent measures indicate that the target's group membership stands as a plausible causal factor to account for members' behavior, a process we call Social Attribution. Implications for current theories of stereotyping are discussed.

Imperatives and commands in Japanese

2017 ◽  
Author(s):  
Nerida Jarkey
Keyword(s):  
Social Hierarchy ◽  
The Social ◽  
The Face ◽  
Group Members ◽  
Face Threat ◽  
Contemporary Standard

This chapter examines the forms and usage of imperatives and command strategies in contemporary standard Japanese. Although commands are highly face-threatening acts in any language, speakers of Japanese encounter particular challenges in using them in socially acceptable ways. Commands are generally only given to those considered ‘below’ the speaker in the social hierarchy, and are normally considered appropriate only when used toward ‘in-group’ members. Further restrictions relate to the identity the speaker wishes to convey. Numerous command strategies have emerged to avoid using the most direct imperative forms, and some of these strategies have gradually come to be reinterpreted as imperative forms themselves, suggesting a loss of their original euphemistic qualities. Furthermore, when issuing commands, speakers often go to considerable lengths to soften the face threat, for example by giving reasons for the command, adding markers of hesitancy, or softening illocutionary particles, and using appropriate honorific language forms.

scholarly journals Amino Acid Repeats Cause Extraordinary Coding Sequence Variation in the Social Amoeba Dictyostelium discoideum

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e46150 ◽  
Author(s):  
Clea Scala ◽  
Xiangjun Tian ◽  
Natasha J. Mehdiabadi ◽  
Margaret H. Smith ◽  
Gerda Saxer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dictyostelium Discoideum ◽  
Sequence Variation ◽  
Social Amoeba ◽  
Coding Sequence ◽  
Amino Acid Repeats ◽  
The Social

scholarly journals Political Vigilante Groups in Ghana: Violence or Democracy?

2020 ◽  
Vol 55 (3) ◽  
pp. 321-338
Author(s):  
Justice Richard Kwabena Owusu Kyei ◽  
Lidewyde H. Berckmoes
Keyword(s):  
Democratic Governance ◽  
Focus Group Discussions ◽  
Group Discussions ◽  
Political Field ◽  
Political Actors ◽  
Electoral Campaigns ◽  
The Social ◽  
Group Members ◽  
Organisational Structures ◽  
Depth Interviews

Literature on political vigilante groups has centred on the violence and conflict that emanate from their activities. This article approaches political vigilante groups as political actors who engage in political mobilisation and participation and therewith also contribute to nation state building. It explores how such groups participate in Ghana’s democratic governance and asks whether violence is an inevitable characteristic. The article builds on individual in-depth interviews and focus group discussions with political vigilante group members in Kumasi and Tamale in 2019. Findings show that political vigilante “youth” appeared to refer primarily to the social position attributed to non-elite groups in the political field. Political vigilante groups are multi-faceted in their organisational structures, membership, and activities both during electoral campaigns and during governing periods. While some groups revert to violence occasionally, the study concludes that political vigilante groups, in enabling different voices to be heard, are also contributing to democratic governance.

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