Evolution of primate societies.
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Adaptation, Physiological↗
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Results for “social evolution”
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[Social rank and depression--an example of "evolutionary psychopathology"].
Affective disorders are pathological alterations of phylogenetically old emotional mechanisms the adaptive function of which is still a matter of debate. According to the social competition hypothesis, depressive syndromes involve activation of a mechanism serving subordination in competitive situations. This mechanism protects the individual from the damaging consequences of an escalating agonistic encounter. The paper critically discusses supporting evidence culled from biological, clinical and psychological findings. Animal models show phenomenological similarities between subordination and depression. In primates affiliative behavior and social bonding are closely linked to rank-related behaviors. Common biochemical and pharmacological features of subordination and depression include an activation of the stress axis, diminished serotonergic neurotransmission and modification by antidepressants. However, the discrimination between a specific subordination reaction and an unspecific stress response is often controversial. Many clinical and psychological aspects of depressive syndromes may be understood as an--exaggerated--submissive behavior, but have rarely been studied in that light. Typical endogenous depression and bipolar disorders challenge the social competition hypothesis. While the manic syndrome, due to its similarity to dominance behavior, supports the link between social competition and affective disorders, the cyclic alteration of mood cannot be sufficiently explained by the social competition hypothesis alone.
Biological Evolution↗
Evolution of eusociality and the soldier caste in termites: influence of intraspecific competition and accelerated inheritance.
We present new hypotheses and report experimental evidence for powerful selective forces impelling the evolution of both eusociality and the soldier caste in termites. Termite ancestors likely had a nesting and developmental life history similar to that of the living family Termopsidae, in which foraging does not occur outside the host wood, and nonsoldier helpers retain lifelong options for differentiation into reproductives. A local neighborhood of families that live exclusively within a limited resource results in interactions between conspecific colonies, high mortality of founding reproductives, and opportunities for accelerated inheritance of the nest and population by offspring that differentiate into nondispersing neotenic reproductives. In addition, fertile reproductive soldiers, a type of neotenic previously considered rare and docile, frequently develop in this intraspecific competitive context. They can be highly aggressive in subsequent interactions, supporting the hypothesis that intercolonial battles influenced the evolution of modern sterile termite soldier weaponry and behaviors.
Animals↗
The politics of dependency estimates: Social Security Board statistics, 1935-1939.
State theorists maintain that Social Security Board (SSB) bureaucrats managed the evolution of public welfare. Institutional politics theory more readily accepts the influences of political interest groups. SSB archival records offer an opportunity to contrast these models and explore the early measurement of old age dependency. In reports designed to protect the 1935 Social Security Act, SSB staff exaggerated the extent of dependency among elderly persons. By 1939, Board statistics clearly showed that children were more impoverished than aged persons. SSB leadership did not repudiate prior estimates and they accepted rising transfers to aged persons, largely because of the political power of interest groups interested in flat pensions. While bureaucrats attempted to control events, an institutional politics approach better explains both the pivotal role of other, political actors and the solidification of the myth of old age impoverishment.
Activities of Daily Living↗
Coexistence under positive frequency dependence.
Negative frequency dependence resulting from interspecific interactions is considered a driving force in allowing the coexistence of competitors. While interactions between species and genotypes can also result in positive frequency dependence, positive frequency dependence has usually been credited with hastening the extinction of rare types and is not thought to contribute to coexistence. In the present paper, we develop a stochastic cellular automata model that allows us to vary the scale of frequency dependence and the scale of dispersal. The results of this model indicate that positive frequency dependence will allow the coexistence of two species at a greater rate than would be expected from chance. This coexistence arises from the generation of banding patterns that will be stable over long time-periods. As a result, we found that positive frequency-dependent interactions over local spatial scales promote coexistence over neutral interactions. This result was robust to variation in boundary conditions within the simulation and to variation in levels of disturbance. Under all conditions, coexistence is enhanced as the strength of positive frequency-dependent interactions is increased.
Animals↗
Complex networks generated by the Penna bit-string model: emergence of small-world and assortative mixing.
The Penna bit-string model successfully encompasses many phenomena of population evolution, including inheritance, mutation, evolution, and aging. If we consider social interactions among individuals in the Penna model, the population will form a complex network. In this paper, we first modify the Verhulst factor to control only the birth rate, and introduce activity-based preferential reproduction of offspring in the Penna model. The social interactions among individuals are generated by both inheritance and activity-based preferential increase. Then we study the properties of the complex network generated by the modified Penna model. We find that the resulting complex network has a small-world effect and the assortative mixing property.
Journal Article↗
[Health and power: the political emergence of AIDS/HIV in Brazil].
This analysis of the construction of political responses to AIDS in Brazil is grounded on a study of the epidemic since its first appearance, against a backdrop formed by the recent history of Brazilian health policy, the period's emerging social movements, and data on AIDS/HIV evolution. Together with period documents, oral sources constitute a fundamental part of the research. The article sees official responses to AIDS from the time of the disease's political emergence in Brazil as evolving through different stages and eventually -- after some problems and not without certain limitations--becoming characterized first and foremost by society's participation.
Acquired Immunodeficiency Syndrome↗
[Epilepsy: an incapacitating disease? Propitiatory topic for a free program for epileptics].
The facts and causes for the margination of people that suffer epilepsy, their problems regards social adaptation and even familiar troubles, all together circumstances that they are carrying since ever in the times until nowadays, are reviewed on the basis of the social and historical aspects and the evolution of ideas regards epileptology. It is stated why such opinions should be reconsidered and instead of which, to divulge appropriate arguments to realize that those persons should enjoy general acceptance and achieve the most adequate development.
Anticonvulsants↗
You can take the ethics out of altruism but you can't take the altruism out of ethics.
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Altruism↗
Evidence of a right-shift factor affecting infant hand-use preferences from 7 to 11 months of age as revealed by latent class analysis.
Infant hand-use preferences for apprehending objects were assessed three times at 7, 9, and 11 months of age for 154 infants (79 males) using a reliable and valid procedure. Two classification procedures (differing in Type I classification error rates) were used to identify an infant's preference (right, left, no preference) at each age, and these data were examined using two- and three-group latent class analysis models. These analyses revealed the importance of using a handedness classification procedure with low Type I error rates and evidence of a right-shift factor similar to that expressed in child and adult handedness. Thus, infant hand-use preferences for apprehending objects are likely a developmental precursor of adult handedness. The relation of the right-shift factor to increased susceptibility to social influences during development and the evolution of human abilities also is discussed.
Adult↗
[Yawning].
Yawning is a normal reflex triggered by arousal, drowsiness, boredom, hunger and emotional conditions and it is associated to several neurological diseases and drug abuse. Its wide presence in the phylogenetic vertebrate scale and even in human fetuses as young as 12 weeks directed the search for the common anatomic and biochemical mechanisms involved. The demonstration that yawning is not connected with high CO2 or low O2 blood levels left aside a prevalent metabolic hypothesis. Its close relationship with the sleep-wake cycle, specially in moments previous to falling asleep and after awaking has been related to changes in personal situation and activity. A single component of this reflex which is to be found exclusively in humans, is the fact that yawning is contagious. Thus, it is considered a component of the adaptative mechanism that is part of the surveillance reflex, becoming a significant paralinguistic evolutive expression aimed at protection and social cohesion. The common anatomical structures and neurochemical systems taking part in yawning, the sleep-wake cycle and the temporal lobe epilepsy may imply that yawning results from a set of protective systems induced by endogenous opiods which intervene in the inhibition and prevention of the temporal lobe epileptic seizures.
Epilepsy, Temporal Lobe↗
[The civil responsibility of the physician in his true evolution].
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Biological Evolution↗
[From isolation to opening: the evolution of the practice of medicine in the canton of Jura. I. The economic and social framework].
Conditions for life from nowadays are compared to those reigning during the first half of this century in the canton Jura, a rural area with some manufactures. Roads were poorly developed and unsafe, hygiene was rudimentary, social security virtually inexistent and perinatal and children's mortality frightfully high. Birth, life and death took place at ones home at candle-light and without assistance. These past conditions are revived to elucidate the enormous medical developments over the past 50 years.
History, 20th Century↗
On the evolution of human aggressivity and the philanthropic drive.
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Aggression↗
[Genetics and social darwinism].
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Biological Evolution↗
[Development of aphasic symptomatology with age. Discussion apropos of an anatomo-clinical case].
Clinical data suggesting that aphasic semeiology undergo some evolution with age are summarized. Three kinds of hypotheses may account for this evolution: (1) a possible evolution with age of the site and extent of ischaemic lesions: (2) an evolution according to age of brain functional organization for language; and (3) evolution with age of psychological and/or social aspects of individuals in whom aphasia occurs. These hypotheses are discussed in the light of a clinico-pathological case of Wernicke's aphasia with logorrheic jargon due to an infarct involving both anterior and posterior parts of the left cortical speech area. This observation does not support the first set of hypotheses implying the lesion's site. On the other hand, as regards the second hypothesis, it is conceivable that the most instrumental features of speech functional organization may undergo a progressive subcorticalization process with age so that it possibly accounts for some age specificity in aphasic semeiology. Finally, the last set of hypotheses--individual's psychological and/or social aspects--although untested here, is thought to be also of some relevance.
Aged↗
Cooperation prevails when individuals adjust their social ties.
Conventional evolutionary game theory predicts that natural selection favours the selfish and strong even though cooperative interactions thrive at all levels of organization in living systems. Recent investigations demonstrated that a limiting factor for the evolution of cooperative interactions is the way in which they are organized, cooperators becoming evolutionarily competitive whenever individuals are constrained to interact with few others along the edges of networks with low average connectivity. Despite this insight, the conundrum of cooperation remains since recent empirical data shows that real networks exhibit typically high average connectivity and associated single-to-broad-scale heterogeneity. Here, a computational model is constructed in which individuals are able to self-organize both their strategy and their social ties throughout evolution, based exclusively on their self-interest. We show that the entangled evolution of individual strategy and network structure constitutes a key mechanism for the sustainability of cooperation in social networks. For a given average connectivity of the population, there is a critical value for the ratio W between the time scales associated with the evolution of strategy and of structure above which cooperators wipe out defectors. Moreover, the emerging social networks exhibit an overall heterogeneity that accounts very well for the diversity of patterns recently found in acquired data on social networks. Finally, heterogeneity is found to become maximal when W reaches its critical value. These results show that simple topological dynamics reflecting the individual capacity for self-organization of social ties can produce realistic networks of high average connectivity with associated single-to-broad-scale heterogeneity. On the other hand, they show that cooperation cannot evolve as a result of "social viscosity" alone in heterogeneous networks with high average connectivity, requiring the additional mechanism of topological co-evolution to ensure the survival of cooperative behaviour.
Biological Evolution↗