Showing papers on "Dominance (ethology) published in 2003"

Social hierarchies: size and growth modification in clownfish.

Abstract: Sex change is not the only way these fish achieve dominance — they grow into the role. Conflicts of interest are part and parcel of living in a social group, although these can reduce the fitness of individual members. Here I show that clownfish (Amphiprion percula) adjust their size and growth rate according to their position in the group hierarchy, maintaining a well-defined size difference with respect to individuals above them in social rank. This strategy to prevent conflict is a surprising departure from the more usual ploy used by many animals of modifying their behaviour within the group1,2.

Attitudes toward group-based inequality: social dominance or social identity?

Abstract: In five studies we explored how the context in which people think about the social structure and the implications of the social structure for one's in-group affect attitudes toward inequality. In Studies 1 and 2 we found that social dominance orientation (SDO) scores reflect attitudes toward specific types of inequality that are salient in context. Consistent with social identity theory, in Studies 3 to 5 we found that SDO scores reflected the interests of specific group identities. Indeed, when we compared existing privileged and disadvantaged groups, and when we manipulated in-group status, we found that participants held more positive attitudes toward inequality when the in-group was privileged, compared to when the in-group was disadvantaged. Across all of our studies, results were consistent with the contention that attitudes toward inequality are group-specific and depend on the social-structural position of salient in-groups. We discuss the implications of our findings for social dominance theory.

Linking Keystone Species and Functional Groups: A New Operational Definition of the Keystone Species Concept

Abstract: The concept of the \"keystone species\" is redefined to allow for the a priori prediction of these species within ecosystems. A keystone species is held to be a strongly interacting species whose top-down effect on species diversity and competition is large relative to its biomass dominance within a functional group. This operational definition links the community importance of keystone species to a specific ecosystem process, e.g., the regulation of species diversity, within functional groups at lower trophic levels that are structured by competition for a limited resource. The a priori prediction of keystone species has applied value for the conservation of natural areas.

Sonic Dominance and the Reggae Sound System Session

Abstract: This article marks the beginning of Julian Henriques’ academic research on reggae sound systems and points to many of the interests that he develops in later research. It discusses dancehall reggae scene in Jamaica at the beginning of the 21st century and the sound engineers who build and operate sound systems. It considers sound in relation to other sensory stimuli, especially visual ones; and music and sound in the context of reggae sound system sessions. Finally, it proposes the concept of “sonic dominance” and the relationship of this quality of sound to the crowd’s embodiment.

Perceptions and Functions of Play and Real Fighting in Early Adolescence

Abstract: The hypothesis is tested that adolescent boys' (mean age of 12.8 years) intrasexual rough-and-tumble play (R&T) is used for dominance and intersexual R&T is used to establish heterosexual relationships. In Study 1, boys' observed R&T was related to both dominance and aggression. In the first half of the school year, R&T occurred primarily between males, possibly to establish dominance. In the second half of the year, both boys and girls engaged in R&T, possibly to establish heterosexual relationships. Counter to the hypothesis, observed aggression increased across the year. In Study 2, youngsters viewed taped R&T bouts in which they were participants or nonparticipants. Participant, more than nonparticipant, males saw R&T as related to dominance whereas participant, more than nonparticipant, females saw it as playful.

Two's Company, Three's a Crowd: Differences in Dominance Relationships in Isolated Versus Socially Embedded Pairs of Fish

Abstract: Summary We performed experiments with cichlid e sh to test whether several basic aspects of dominance were the same in isolated pairs as in pairs within a social group of three or four. We found that the social context, whether a pair was isolated or within a group, strongly affected the basic properties of dominance relationships. In particular, the stability of relationships over time, the replication of relationships in successive meetings, and the extent of the loser effect were all signie cantly less in socially embedded pairs than in isolated pairs. We found no signie cant winner effect in either isolated or socially embedded pairs. These e ndings call into question many current approaches to dominance that do not consider social context as an important factor in dominance behavior. These e ndings also cast serious doubt on the validity of empirical and theoretical approaches based on dyadic interactions. Among these approaches are game theoretic models for the evolution of aggressive behavior, experimental designs evaluating how asymmetries in attributes ine uence the outcome of dominance

The evolution of social dominance II: Multi-player models

Abstract: The social hierarchies observed in natural systems often show a high degree of transitivity. Transitive hierarchies do not only require rank differentiation within pairs of individuals but also a higher level ordering of relations within the group. Several authors have suggested that the formation of linear hierarchies at the group level is an emergent property of individual behavioural rules, referred to as winner and loser effects. Winner and loser effects occur if winners of previous conflicts are more likely to escalate the current conflict, whereas the losers of previous conflicts are less likely to do so. According to this idea, an individual's position in a hierarchy may not necessarily reflect its fighting ability, but may rather result from arbitrary historical asymmetries, in particular the history of victories and defeats. However, if this is the case, it is difficult to explain from an evolutionary perspective why a low ranking individual should accept its subordinate status. Here we present a game theoretical model to investigate whether winner and loser effects giving rise to transitive hierarchies can evolve and under which conditions they are evolutionarily stable. The main version of the model focuses on an extreme case in which there are no intrinsic differences in fighting ability between individuals. The only asymmetries that may arise between individuals are generated by the outcome of previous conflicts. We show that, at evolutionary equilibrium, these asymmetries can be utilized for conventional conflict resolution. Several evolutionarily stable strategies are based on winner and loser effects and these strategies give rise to transitive hierarchies.

The evolution of social dominance I: Two-player models

Abstract: A difference in dominance rank is an often-used cue to resolve conflicts between two animals without escalated fights. At the group level, adherence to a dominance convention efficiently reduces the costs associated with conflicts, but from an individual's point of view, it is difficult to explain why a low ranking individual should accept its subordinate status. This is especially true if, as suggested by several authors, dominance not necessarily reflects differences in fighting ability but rather results from arbitrary historical asymmetries. According to this idea, rank differentiation emerges from behavioural strategies, referred to as winner and loser effects, in which winners of previous conflicts are more likely to win the current conflict, whereas the losers of previous conflicts are less likely to do so. In order to investigate whether dominance, based on such winner and loser effects, can be evolutionarily stable, we analyse a game theoretical model. The model focuses on an extreme case in which there are no differences in fighting ability between individuals at all. The only asymmetries that may arise between individuals are generated by the outcome of previous conflicts. By means of numerical analysis, we find alternative evolutionarily stable strategies, which all utilize these asymmetries for conventional conflict resolution. One class of these strategies is based on winner and loser effects, thus generating evolutionarily stable dominance relations even in the absence of differences in resource holding potential.

Anybody can be a boss but only certain people make good subordinates: behavioral impacts of striving for dominance and dominance aversion.

Abstract: The present study investigated whether people in assigned subordinate or dominant roles differ in their dominance behavior according to whether they initially wanted a subordinate or a dominant role. Sixty-six females and 72 males interacted twice for 8 mins in same-gender dyads. Prior to the interaction, participants could indicate whether they preferred to take a subordinate or a dominant role. Roles were then assigned randomly. Both interactions were videotaped and later coded for perceived dominance and speaking time. Results showed that for assigned subordinates, those who initially wanted to be in the dominant position were perceived as more dominant and behaved more dominantly than those who initially wanted to be in the subordinate role. For assigned high-dominance people, there was no difference in perceived dominance and behavioral dominance between those who initially wanted the dominant versus subordinate position.

Beyond Dominance and Affection: Living with Rabbits in Post-Humanist Households

Abstract: Nearly 20 years age, Yi-Fu Tuan wrote his influential Dominance and Affection:The Making of Pets (1984), which argued that human affection for domestic animals is inseparable from dominance. Today, cultural critics persist in the view that companion animals are compromised, even degraded, because they are controlled by humans. The essay attempts to rethink the relationship between humans and companion animals beyond the freedom-dominance binary. It argues for a conceptual approach that defers confidant interpretation of animals while dramatically relaxing control of them within human settings. It suggests that this approach be called a "performance ethic" and offered the House Rabbit Society as a model.

Methodological considerations in measurement of dominance in primates

Abstract: The strength of dominance hierarchy in a group of animals needs to be quantitatively measured since it influences many other aspects of social interactions. This article discusses three attempts made by previous researchers to measure the strength of hierarchy. We propose a method which attempts to rectify the lacunae in the previous attempts. Data are used from a group of Japanese macaques housed in a colony. A method to calculate strength of hierarchy has been illustrated and a procedure has been suggested to normalize the dominance scores in order to place the ranks of individuals on an interval scale.

Male‐male mountings in polyandrous bearded vultures Gypaetus barbatus: an unusual behaviour in raptors

Abstract: Male-male mountings appear to be very common in polyandrous bearded vulture Gypaetus barbatus trios. We observed sexual activity in two trios that occupied the same territory in different years. We recorded a total of 167 copulation attempts. The percentage of male-male mountings recorded was 26.1 and 11.4%, in the period of 1991-1992 and 2000-2001, respectively, with respect to total, homo- and heterosexual matings. We conclude that homosexual interactions do not appear to be directly associated with intrasexual competition (i.e. hierarchical dominance, sperm competition). Rather, our results are more consistent with the idea that this behaviour can regulate the aggression of the males in these groups.

Determinants of social rank in female black-capped chickadees (Poecile atricapilla)

Abstract: Black-capped chickadees (Poecile atricapilla) mate assortatively by social rank. Previous field studies sug - gest that intrinsic characteristics of females may influence success at pairing with dominant males. Here we examined factors leading to dominance using dyads of captive unfamiliar females. The owner-intruder hypothesis predicts that prior residency determines dominant-subordinate relationships. The resource-value hypothesis suggests that social status is initially determined by need and the relationship persists through familiarity of the interactants. The resource holding potential hypothesis suggests that individuals win in dyadic contests because of intrinsic characteristics such as size or age. We tested the owner-intruder and resource-value hypotheses by allowing females prior residency in aviaries where dominance interactions subsequently occurred and by food depriving the intruders. Post-hoc comparisons of dominant- subordinate attributes tested the resource holding potential hypothesis. We found that owners were more likely to win interactions. Hungry individuals showed no competitive advantage. Dominants and subordinates did not differ in mor- phology or age. Our results agree with data from willow tits (Parus montanus) which show that captive females estab- lish dominance independent of males and that prior residence plays a key role. These findings, together with field studies, suggest that assortative mating in chickadees results, at least in part, from intrasexual interactions among females.

Social relationships and social structure of the mound-building mouse ( Mus spicilegus ) in intraspecific cage groups

Abstract: The social relationships of Mus spicilegus were studied in intraspecific cage groups for a month during the reproductive period to clarify the role of intraspecific aggressiveness in shaping social structure and in reproduction. The mound-building mice were captured from a wild population in northern Bulgaria. A total of 13 groups, 5 male, 4 female, and 4 male–female groups, were tested. Each group consisted of five unfamiliar adults. The experiments were carried out in 100×100-cm glass cages. The patterns of behaviour and the dominant–subordinate structure within each group were investigated. A dominance index for every individual in the group was calculated. During the period of establishment of the hierarchical structure in the groups a high level of aggressiveness was registered among individuals. About half of the subdominants and subordinates were found dead, with or without obvious marks of injury. Male–male interactions were more aggressive compared to these of females. Dominant–subordinate relationships between individuals of the same sex were observed in the mixed groups. A link between dominance rank and reproduction was established. The dominant male and the dominant female formed a pair and started to breed. Based on these findings it can be assumed that the aggressiveness of M. spicilegus is an adaptation to its life in the fields, where dominance is likely to be an essential factor in individual reproductive success. It is likely that the successful rearing of offspring in natural populations, which are exposed to strong biotic and abiotic impact, necessitates the existence of monogamous relationships.

Democracy and party dominance in Kenya and South Africa : a comparative study of the Kenya African National Union and the African National Congres

Abstract: Kenya and South Africa can be described as dominant party systems, under the dominance of the Kenya African National Union CKANU) and the African National Congress CANC) respectively. A dominant party system is in essence a democracy. The spirit of democracy may, however, apparently be contradicted by the weight of party dominance, thus questioning the content of and prospects for democracy under party dominance in both Kenya and South Africa. The study is a comparative analysis of party dominance in Kenya and South Africa. The main objective is to exan1ine the relationship between party dominance and democracy in both countries. It seeks to find out how party dominance is reproducing itself and surviving the post 1990 transition processes in Kenya and South Africa. More importantly, the study also seeks to find out how party dominance impacts upon institutions that support or uphold democratization and subsequently democracy. The findings of the study demonstrate that party dominance has reproduced itself and survived the post-1990 period, and is also impacting upon democratization and democracy. The dominant parties take a similar trajectory in pursuit of dominance over the state and its apparatuses. However, they differ when it comes to their relationship with the civil society. That between KANU and civil society is antagonistic, as the ruling party seeks to augment political power through authoritarian dominance of the latter to, while that of the ANC and civil society is responsive, as the former seeks to enhance political stability in the country.

Lorenz, Pareto, Pigou: Who Scores Best? Experimental Evidence on Dominance Relations of Income Distributions

Abstract: Using an experiment with material incentives, this paper investigates the violation of composite dominance relationships, viz. absolute Pareto dominance, Pareto rank dominance, transfer dominance, Lorenz dominance, and generalized Lorenz dominance. Moreover, we test tail independence. The experiment consists of two treatments, a self-concern mode (in which each subject expects payoffs according to her own choices), and a social-planner mode (in which subjects form their preferences without any chance of receiving payoffs when they became effective). The main focus of this paper centers on the behavioral shifts between the self-concern and the social-planner modes. We show, first, that subjects' behavior is different under the two treatments. Second, we show that there are less violations of the two Pareto dominance relations and of generalized Lorenz dominance and more violations of Lorenz dominance and of transfer dominance under the self-concern mode than under the social-planner mode. Within these groups, behavior is more similar under the self-concern mode than under the social-planner mode. Tail independence is widely rejected.

Dominance Functions for Parametric Lagrangians

Abstract: We discuss the concept of dominance functions for parametric Lagrangians together with important examples and various applications to the existence and regularity theory for minimizers of parametric functionals, and for the construction of unstable stationary surfaces. The focus lies on the construction of a perfect dominance function based on ideas of Morrey.

Functional-Lexical Code-Mixing Patterns as Evidence for Language Dominance in Young Bilingual Children: A Minimalist Approach

Abstract: In this paper we address the issue of how language is represented in the bilingual mind. We specifically investigate functional-lexical mixed utterances of the type Det + N as produced by young English/Spanish bilingual children. Functional-lexical mixings are defined here as constituents formed by a functional morpheme (either free or bound) from one language and a lexical (referential) morpheme from the other. Examples of English/Spanish Det + N mixings are given in (1) and (2).

Birth order effects in dominance: failure to support Sulloway's view.

Abstract: Contrary to Sulloway's 1996 assertion that firstborns should score higher than laterborns on measures of dominance, the dominance scores for 76 firstborn undergraduate students (50 women, 26 men) did not differ significantly from the scores of 75 laterborn students (48 women, 27 men) on the 16PF dimension of Dominance vs Submissiveness (Factor E). Further research into possible differences in performance strategies between laterborns and firstborns in childhood vs adulthood is necessary to evaluate Sulloway's theory of ordinal position definitively.

Paternal occupation and offspring sex ratio

Abstract: Between 1961 and 1997, there were 15 reports of unusual secondary sex ratios related to paternal occupation. Thirteen of these documented a statistically significant predominance of female births (low secondary sex ratios) to fathers working in specific occupations. Findings are summarized, as are authors' suggestions about possible causes for the observed phenomenon. In addition, a new study is reported, replicating the findings of low offspring sex ratios in the children of male anaesthetists. Discussion focuses on four possible explanations of the findings – sampling error, differential damage to sperm, the Trivers and Willard hypothesis (Trivers and Willard 1973), and the maternal dominance hypothesis (Grant 1990, 1994, 1998b).

Probing whole number dominance with fractions

Abstract: Children’s whole number schemes can interfere with their efforts to learn fractions. To what extent do these schemes persist for secondary school students? This paper reports on the development and piloting of an interview designed to identify and probe inappropriate whole number strategies for working with fractions among secondary students. The interview showed that these strategies are still prevalent among Year 8 students. Among others who use appropriate multiplicative strategies the interview showed that some of these are still not confident in challenging instances of inappropriate whole number thinking.