Matching Patterns When Group Size Exceeds Two

2017 ◽  
Vol 9 (1) ◽  
pp. 352-384
Author(s):  
Christian Ahlin
Keyword(s):  
Group Size ◽  
The Other ◽  
Assortative Matching ◽  
Potential Equilibrium

We study one-sided matching when groups with n > 2 members are being formed. Type-complementarity rules out all but the rank-ordered grouping. Type-substitutability (for example, matching to share risk) rules out much less. It requires that every two groups must be “intertwined,” in that each dominates the other at some rank. Intertwined matching is necessary and, in one context, sufficient for any grouping to be a potential equilibrium. But there are many intertwined matching patterns when n > 2. Thus, substitutability can be observationally similar to complementarity; we demonstrate this by showing that dyadic regressions can register intertwined (negative assortative) matching as homogeneous matching. (JEL C78)

scholarly journals Social Influence of Competing Groups and Leaders in Opinion Dynamics

2020 ◽  
Author(s):  
Catherine A. Glass ◽  
David H. Glass
Keyword(s):  
Social Influence ◽  
Group Size ◽  
Computer Simulations ◽  
Parameter Space ◽  
Optimal Strategies ◽  
Opinion Dynamics ◽  
The Other ◽  
Opinion Leaders ◽  
The Impact

Abstract This paper explores the influence of two competing stubborn agent groups on the opinion dynamics of normal agents. Computer simulations are used to investigate the parameter space systematically in order to determine the impact of group size and extremeness on the dynamics and identify optimal strategies for maximizing numbers of followers and social influence. Results show that (a) there are many cases where a group that is neither too large nor too small and neither too extreme nor too central achieves the best outcome, (b) stubborn groups can have a moderating, rather than polarizing, effect on the society in a range of circumstances, and (c) small changes in parameters can lead to transitions from a state where one stubborn group attracts all the normal agents to a state where the other group does so. We also explore how these findings can be interpreted in terms of opinion leaders, truth, and campaigns.

scholarly journals The Infertility Trap: The Fertility Costs of Group-Living in Mammalian Social Evolution

2021 ◽  
Vol 9 ◽  
Author(s):  
Robin I. M. Dunbar ◽  
Susanne Shultz
Keyword(s):  
Group Size ◽  
Social Evolution ◽  
Low Cost ◽  
Social Groups ◽  
Group Living ◽  
The Other ◽  
Risk Averse ◽  
Limit Group ◽  
Grouping Patterns ◽  
Environmental Demands

Mammal social groups vary considerably in size from single individuals to very large herds. In some taxa, these groups are extremely stable, with at least some individuals being members of the same group throughout their lives; in other taxa, groups are unstable, with membership changing by the day. We argue that this variability in grouping patterns reflects a tradeoff between group size as a solution to environmental demands and the costs created by stress-induced infertility (creating an infertility trap). These costs are so steep that, all else equal, they will limit group size in mammals to ∼15 individuals. A species will only be able to live in larger groups if it evolves strategies that mitigate these costs. We suggest that mammals have opted for one of two solutions. One option (fission-fusion herding) is low cost but high risk; the other (bonded social groups) is risk-averse, but costly in terms of cognitive requirements.

scholarly journals The group size effect and synchronization of vigilance in the Tibetan wild ass

2020 ◽  
Author(s):  
Xinxin Wang ◽  
Le Yang ◽  
Yumeng Zhao ◽  
Cong Yu ◽  
Zhongqiu Li
Keyword(s):  
Size Effect ◽  
Group Size ◽  
Nature Reserve ◽  
Prey Species ◽  
The Other ◽  
Effective Strategy ◽  
Positive Correlation ◽  
Group Size Effect ◽  
Wild Ass ◽  
Group Members

Abstract Vigilance behavior is considered as an effective strategy for prey species to detect predators. An individual benefits from living in a group by reducing the time spent being vigilant without affecting the probability of detecting a predator. However, the mechanism producing a decrease in vigilance with increasing group size is unclear. Many models of vigilance assume that group members scan independently of one another. Yet in recent studies, the other 2 patterns of vigilance, coordination and synchronization, were reported in some species. In 2 summers (2018 and 2019), we studied the group-size effect on vigilance and foraging of Tibetan wild ass in Chang Tang Nature Reserve of Tibet. We also tested whether individuals scan the environment independently, tend to coordinate their scans, or tend to synchronize their vigilance. The results showed that individuals decreased the time spent on vigilance with increasing group size, while increased the time spent foraging. Group members scanned the environment at the same time more frequently and there was a positive correlation between group members’ behaviors, indicating that Tibetan wild asses tend to synchronize their vigilance.

Matching under Imperfectly Transferable Utility

2017 ◽  
Author(s):  
Pierre-André Chiappori
Keyword(s):  
Theoretical Framework ◽  
The Other ◽  
Assortative Matching ◽  
Transferable Utility ◽  
Matching Models

This chapter considers matching models under imperfectly transferable utility (ITU). Some of the techniques used in the transferable utility (TU) case can be extended to an ITU framework; for example, the Spence-Mirrlees condition, which is sufficient for positive assortative matching (PAM), can be generalized to the ITU case. Furthermore, individual utilities may be recovered (up to a constant, as in the TU case), using techniques which are essentially similar to their TU counterpart. After providing an overview of the basic notions and theoretical framework of matching under ITU, the chapter discusses the recovery of individual utilities, PAM, and econometrics of ITU. It also presents two examples of applications of ITU techniques, one dealing with matching on wages and the other with endogenous Pareto weights.

From individual to collective vigilance in wild boar (Sus scrofa)

1992 ◽  
Vol 70 (8) ◽  
pp. 1632-1635 ◽  
Author(s):  
Pierre-Yves Quenette ◽  
Jean-François Gerard
Keyword(s):  
Wild Boar ◽  
Group Size ◽  
Sus Scrofa ◽  
Functional Approach ◽  
The Other ◽  
Motor Variability ◽  
Proximate Causation ◽  
Vigilance Behaviour ◽  
The Mean ◽  
The Individual

Vigilance behaviour of captive wild boars at feeding points was investigated using films. Results show that individual vigilance decreased with increasing group size, especially between solitary individuals and groups of 2. Moreover, the collective vigilance was, whatever the group size, below the individual vigilance in solitary animals. The study of the motor variability of vigilance behaviour allows three types of movement to be distinguished. The mean durations of each type vary largely, but are almost constant whatever the group size. On the other hand, the relative proportions of the vigilance acts change according to group size. Although previous studies of vigilance are in keeping with the functional approach of behaviour, these data are interpreted in terms of proximate causation. A mechanism based on allelomimesis is proposed to explain the results.

scholarly journals Primate hippocampus size and organization are predicted by sociality but not diet

2019 ◽  
Vol 286 (1914) ◽  
pp. 20191712 ◽  
Author(s):  
Orlin S. Todorov ◽  
Vera Weisbecker ◽  
Emmanuel Gilissen ◽  
Karl Zilles ◽  
Alexandra A. de Sousa
Keyword(s):  
Sex Differences ◽  
Home Range ◽  
Group Size ◽  
Phylogenetic Signal ◽  
Spatial Navigation ◽  
Ecological Factors ◽  
Hippocampal Volume ◽  
The Other ◽  
Sex Dimorphism ◽  
Cornu Ammonis

The hippocampus is well known for its roles in spatial navigation and memory, but it is organized into regions that have different connections and functional specializations. Notably, the region CA2 has a role in social and not spatial cognition, as is the case for the regions CA1 and CA3 that surround it. Here, we investigated the evolution of the hippocampus in terms of its size and organization in relation to the evolution of social and ecological variables in primates, namely home range, diet and different measures of group size. We found that the volumes within the whole cornu ammonis coevolve with group size, while only the volume of CA1 and subiculum can also be predicted by home range. On the other hand, diet, expressed as a shift from folivory towards frugivory, was shown to not be related to hippocampal volume. Interestingly, CA2 was shown to exhibit phylogenetic signal only against certain measures of group size, but not with ecological factors. We also found that sex differences in the hippocampus are related to body size sex dimorphism. This is in line with reports of sex differences in hippocampal volume in non-primates that are related to social structure and sex differences in behaviour. Our findings support the notion that in primates, the hippocampus is a mosaic structure evolving in line with social pressures, where certain subsections evolve in line with spatial ability too.

scholarly journals Primate hippocampus size and organization are predicted by sociality but not diet

2019 ◽  
Author(s):  
Orlin S. Todorov ◽  
Vera Weisbecker ◽  
Emmanuel Gilissen ◽  
Karl Zilles ◽  
Alexandra A. de Sousa
Keyword(s):  
Sex Differences ◽  
Home Range ◽  
Group Size ◽  
Phylogenetic Signal ◽  
Spatial Navigation ◽  
Ecological Factors ◽  
Hippocampal Volume ◽  
The Other ◽  
Sex Dimorphism ◽  
Cornu Ammonis

AbstractThe hippocampus is well known for its roles in spatial navigation and memory, but it is organized into regions that have different connections and functional specializations. Notably, the region CA2 has a role in social and not spatial cognition, as is the case for the regions CA1 and CA3 that surround it. Here we investigated the evolution of the hippocampus in terms of its size and organization in relation to the evolution of social and ecological variables in primates, namely home range, diet and different measures of group size. We found that the volumes within the whole cornu ammonis coevolve with group size, while only the volume of CA1 and subiculum can also be predicted by home range. On the other hand, diet, expressed as a shift from folivory toward frugivory, was shown to not be related to hippocampal volume. Interestingly, CA2 was shown to exhibit phylogenetic signal only against certain measures of group size but not with ecological factors. We also found that sex differences in the hippocampus are related to body size sex dimorphism. This is in line with reports of sex differences in hippocampal volume in non-primates that are related to social structure and sex differences in behaviour. Our findings support the notion that in primates, the hippocampus is a mosaic structure evolving in line with social pressures, where certain subsections evolve in line with spatial ability too.

scholarly journals What Motivates Restaurant Customers to Tip: Evidence from the Czech Republic

2018 ◽  
Vol 66 (1) ◽  
pp. 273-282
Author(s):  
Michal Kvasnička
Keyword(s):  
Service Quality ◽  
Group Size ◽  
Social Norm ◽  
Descriptive Statistics ◽  
The Other ◽  
Policy Capturing ◽  
Good Service ◽  
The Czech Republic ◽  
The Social ◽  
The Impact

Although the literature on tipping is enormous, it is still unclear what motivates people to tip. In particular, it is unresolved how tips depend on service quality, patronage frequency, and group sizes, why people tip more for better service if they do, and why they tip at all when they can avoid it. This study aims to fill this gap. It uses survey data to explore what motivates Czech restaurant customers to tip. Reasons for tipping, factors constituting service quality, and reasons for tipping more for better service are explored by descriptive statistics. The impact of service quality, group size, and patronage frequency on tips is assessed by random effects estimator and simple policy capturing. The results show that Czech customers tip mostly because of gratitude, to follow the social norm, and to avoid feeling guilty when not tipping. Most Czechs do not tip to supplement waiters’ wages. Their tips are strongly influenced by service quality, which includes the whole experience of a dinner in a restaurant and not only the waiter’s performance. They reward a good service because it is fair, out of gratitude, and to motivate the waiters to provide good service in the future, but not because it is prescribed by social norms. On the other hand, there is little evidence that their tips depend on patronage frequency or group size.

scholarly journals Neophobia in 10 ungulate species—a comparative approach

2021 ◽  
Vol 75 (7) ◽  
Author(s):  
Alina Schaffer ◽  
Alvaro L. Caicoya ◽  
Montserrat Colell ◽  
Ruben Holland ◽  
Lorenzo von Fersen ◽  
...  
Keyword(s):  
Social Integration ◽  
Group Size ◽  
Individual Characteristics ◽  
The Other ◽  
Comparative Approach ◽  
Ecological Characteristics ◽  
Network Analyses ◽  
Barbary Sheep ◽  
Dietary Breadth ◽  
Study Species

Abstract Neophobia (the fearful reaction to novel stimuli or situations) has a crucial effect on individual fitness and can vary within and across species. However, the factors predicting this variation are still unclear. In this study, we assessed whether individual characteristics (rank, social integration, sex) and species socio-ecological characteristics (dietary breadth, group size, domestication) predicted variation in neophobia. For this purpose, we conducted behavioral observations and experimental tests on 78 captive individuals belonging to 10 different ungulate species—an ideal taxon to study inter-specific variation in neophobia given their variety in socio-ecological characteristics. Individuals were tested in their social groups by providing them with familiar food, half of which had been positioned close to a novel object. We monitored the individual latency to approach and eat food and the proportion of time spent in its proximity. Using a phylogenetic approach and social network analyses, we showed that across ungulate species neophobia was higher in socially more integrated individuals, as compared to less integrated ones. In contrast, rank and sex did not predict inter-individual differences in neophobia. Moreover, species differed in their levels of neophobia, with Barbary sheep being on average less neophobic than all the other study species. As group size in Barbary sheep was larger than in all the other study species, these results support the hypothesis that larger group size predicts lower levels of neophobia, and confirm ungulates as a highly promising taxon to study animal behavior and cognition with a comparative perspective. Significance statement In several species, individuals may respond fearfully to novel stimuli, therefore reducing the risks they may face. However, it is yet unclear if certain individuals or species respond more fearfully to novelty. Here, we provided food to 78 individual ungulates with different characteristics (e.g., sex, rank, social integration, group size, domestication, dietary breadth) in different controlled conditions (e.g., when food was close to novel or to familiar objects). Across species, we found that socially integrated individuals responded more fearfully in all species. Moreover, being in larger groups decreased the probability of fearfully responding to novelty.

Investment Trios Are Less Prone to the Hot Hand and Gambler’s Fallacies and Make Better Investment Strategies

2018 ◽  
Vol 4 (2) ◽  
pp. 123
Author(s):  
Pamela Denice Arao ◽  
Danyel Brendan Arizabal ◽  
Seanne Veniene Esguerra
Keyword(s):  
Experimental Study ◽  
Group Size ◽  
The Other ◽  
Investment Strategies ◽  
Hot Hand ◽  
Investment Returns ◽  
Minimum Group ◽  
Profit Maximizing ◽  
Better Than ◽  
Rational Decisions

An experimental study was conducted to determine the minimum group size for which the mitigating effect for the hot hand and gambler’s fallacies can be felt. This is quantified by looking if groups are as prone to the hot hand and gambler’s fallacies in making decisions as their individual counter parts. Results suggest that groups maximize their investment returns better than individuals as the former choose to decide on their own more and rely on the experts’ opinions less. Triads are the least biased with the hot hand and gambler’s fallacies and thus are able to make more rational decisions and consequently maximize their investments better than the other treatments.These data allowed us to recognize the benefits of forming investment clubs consisting of three members since their decisions are more likely in line with the profit maximizing strategy in comparison with the decisions made by pairs and individuals.

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