Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “social evolution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources
PubMed1994

Postnatal mental illness: a transcultural perspective.

The three main conditions that are associated with childbirth are the maternity blues, postnatal depression and post-partum psychosis. The prevalence of the blues, which are mild, transient and very common disturbances of postnatal mood, does not appear in a major way to be related to environmental, social or cultural factors. Postnatal depression, which has a predominantly psychosocial etiology, surprisingly does not appear to vary in incidence across different cultures in the few studies reported that permit direct comparisons. There is also no good evidence for or against the theory that postnatal depression is partly the consequence of the customs and rituals that traditionally mark the transition to parenthood being stripped away in developed Western societies. However, the lack of relevant research and limitations of method severely restrict any conclusions that can be drawn. There is much firmer evidence for a consistent incidence of post-partum psychosis across cultural and ethnic divides; this observation, together with clinical data and historical evidence of an unchanging incidence rate during the past 150 years, points to a primarily endogenous etiology for the psychoses, which may be triggered by the physiology of childbirth. The transcultural approach to postnatal psychiatric disorders provides a unique opportunity not only to test hypotheses about social and cultural contributions to the etiology of psychotic and non-psychotic reactions to childbirth, but also an opportunity to study the ways in which social factors can influence the evolution of psychopathology. It is also possible that in some cultures the family and social milieu may play a major part in buffering infants from the adverse effects of maternal postnatal illness, but the evidence is anecdotal. Systematic research across cultures will lead to better recognition of maternal illness as well as to better prevention and management.

Cross-Cultural Comparison↗
PubMed2004

[What is Machiavellian intelligence? Views on a little appreciated side of the psyche].

Ethological and evolutionary psychological research has produced evidence that intelligence is not a monolithic functional entity but includes a number of specialized mental abilities to cope with life which even stem from diverse evolutionary origins. One of these subforms of intelligence is called "Machiavellian intelligence," named after the 15/16th century Italian politician and author, Niccolo Machiavelli. It provides individuals or groups with a means of social manipulation in order to attain particular goals. Thus, it builds the psychological basis for the display of power in social groups. Machiavellian intelligence can be observed and evaluated in bands of primates as well as in humans, and there are even tools for measurement in the latter.

Animals↗
PubMed1985

Genital signalling and the coexistence of male vervet monkeys (Cercopithecus aethiops pygerythrus).

To ascertain the social significance of male genital colouration two troops of vervets, one free-ranging and one caged, were observed. It was found that genital signals were associated with intermale agonism. It is suggested that this communicatory system regulates the behaviour of competitors and may thereby have facilitated the evolution of a multimale social system.

Animal Communication↗
PubMed2001

Cultural variation: considerations and implications.

Cultural systems vary widely across the world. Partly this is due to different cultures' occupying different ecological and environmental niches. But partly it is due to similar circumstances giving rise to multiple stable equilibriums, each with a distinct cultural form. Using insights and examples from various fields, this article illustrates the way that multiple equilibriums can emerge and the forces that push a culture toward one equilibrium point or another. Considerations of game theory principles, mutual interdependence, historical circumstance, dependence on initial conditions, and crucial choice points are highlighted in discussing the ways humans create and re-create their culture. Cultural traits develop within physical, social, intracultural, and intercultural niches, and implications of this for how culture might be studied and the benefits of combining an "equilibrium" perspective and a "meaning" perspective are discussed.

Cultural Characteristics↗
PubMed2000

Clinical epidemiology and research on HIV infection in Switzerland: the Swiss HIV Cohort Study 1988-2000.

BACKGROUND AND OBJECTIVES: The Swiss HIV Cohort Study (SHCS) was initiated in 1988 and represented the main scientific component of the comprehensive response to the AIDS epidemic in Switzerland. It brought together physicians and scientists from five university hospitals (Basel, Berne, Geneva, Lausanne and Zurich) and two Cantonal hospitals (Lugano and St. Gallen). The objective of SHCS was, and still is, to produce rapid, high quality patient-oriented medical research in the field of HIV infection. METHODS: SHCS is a prospective population-based cohort study. Any HIV-infected person aged > or = 16 years is eligible to participate. Data collection and study procedures are standardised. Data quality and protocol monitoring are conducted at the coordination and data centre in Lausanne. Detailed information on demographics, income, mode of HIV acquisition, risk behaviours, clinical events, laboratory results, treatment and treatment tolerance is collected at registration and at 6-monthly intervals. RESULTS: Since 1996, 10,600 persons have been enrolled and the SHCS study population is considered fairly representative of the HIV-infected population in Switzerland, at least in terms of gender and mode of HIV acquisition. In 1999, 4600 patients were actively followed up and more than 70% of patients were receiving highly active antiretroviral therapy (HAART). As a consequence, mortality and the incidence of HIV-related opportunistic infections have decreased significantly in the recent past. Between 1996 and 2000, 91 original manuscripts have been published by SHCS scientists and physicians, almost exclusively in peer-reviewed journals. A wide range of scientific questions have been addressed, including HIV primary infection, the natural history of HIV infection, the clinical and biological impact of HAART, drug resistance, risk factors for disease evolution including the timing of treatment initiation, the role of CD4 receptors, the validity of HIV surveillance reports, determinants of treatment access and tolerance, clinical trials of new drug combinations, the interruption of prophylaxis following a favourable response to HAART and issues relating to quality of life and interaction between income, social level and disease evolution. CONCLUSION: The SHCS has had, and continues to have, a significant impact on medical practice, public health and research in Switzerland and beyond. It represents a network of excellence which has brought together and fostered intensive collaboration between physicians and institutions throughout this country and beyond. This was possible thanks to the support of the Federal Office of Public Health and the commitment of primary care physicians, researchers and patients. This project may be model for focused and prioritised multicentre and transdisciplinary research programmes.

AIDS-Related Opportunistic Infections↗
PubMed1993

Friendship and the evolution of co-operation.

Recent theoretical research on the repeated Prisoner's Dilemma game (PD) suggests that the evolution of co-operative behaviour depends on the rate at which social groups break apart and new groups form. Long-lasting social groups tend to favour the evolution of co-operation. It is therefore of interest to construct models in which individuals must choose whether to maintain their current social relationships. This is done in the present paper, and the analysis suggests that unco-operative individuals will seek to move quickly from one social relationship to another, while co-operative individuals will seek to maintain relationships with other co-operative individuals. As a result of their differing decisions about changing social relationships, co-operators tend to interact with other co-operators to a greater extent than do unco-operative individuals, and this difference is an important determinant of the results of the model. In contrast to the original analyses of the repeated Prisoner's Dilemma, the model presented here allows for the existence of stable equilibria with both co-operative and unco-operative individuals simultaneously present in the same population. It is proved that the position of these equilibria (and hence the frequency of co-operators) depends on the size of the various payoffs that define the Prisoner's Dilemma game. In addition, it is proved that co-operation can be maintained at a high frequency so long as co-operators are able to maintain their relationships with other co-operators over long periods of time. This is true even if unco-operative individuals are able to move from one relationship to another at a very high rate.

Biological Evolution↗
PubMed1987

Can pediatrics meet the challenge of social ill health?

The American Academy of Pediatrics mission statement equates physical, mental, and social health--indeed a major challenge for the profession. This article outlines the magnitude and evolution of physical, mental, and social problems presented to pediatricians during this century. Included are manifestations, and some causes, of social ill health; the response of research and education to the problems; and future steps needed if the challenge is to be met. The unanswered and disturbing question presents itself: Can, or should, pediatrics seriously attempt to meet the challenge of social ill health?

Humans↗
PubMed1987

Heavy and problem drinking in an American blue-collar population: implications for prevention.

This paper presents the findings of a prevention-oriented research project designed to identify the familial and socio-environmental precursors of heavy drinking in a blue-collar population. Using an ethnographic and primarily qualitative approach to data collection, this study examines alcohol use and drinking behavior in relation to both the family as a unit, as well as the sociocultural context in which it is embedded. It reports primarily on features of cultural, workplace, and community environments that are related to heavy or moderate drinking in the subject population. The sample consists of 30 families, 15 where the father is a heavy drinker and 15 where he is a moderate drinker. The sample was drawn from the workforce of a large manufacturing plant that closed in 1982. The social organization of the workplace, including the important factors of job alienation, job stress, inconsistent social controls, and the evolution of a 'drinking culture,' is implicated by this research to be the primary vehicle for promoting high levels of alcohol use. Although the role of the workplace in encouraging certain alcohol behaviors was predominant, the data suggest that it alone may not be sufficient for causing alcohol problems. In particular, the central importance of drinking in work-related social contexts and the relative permissiveness of the work environment was found to promote heavy drinking among individuals who were of sociocultural backgrounds where heavy drinking was permitted or even encouraged; reported a lack of effective male role models when growing up; and restricted leisure activities to male-oriented peer groups most often met through work-related contexts. Conversely factors that appeared protective of developing high-risk drinking patterns were family religious involvement, and participation of fathers in non-work related social groups that usually involved their wives and children. We conclude the paper by offering suggestions as to how these findings might lead to constructive strategies for the primary prevention of alcohol problems in the context of the workplace and community.

Adult↗
PubMed2003

Reproductive skew and the origin of sterile castes.

Reproductive skew theory has not heretofore formally addressed one of the most important questions in evolutionary biology: How can whole-life sterile castes evolve? We construct a transactional skew model investigating under what conditions a subordinate in a multimember group is favored to develop into a morphologically specialized worker caste. Our model demonstrates that, contrary to former expectations, the ecological and genetic conditions favoring caste differentiation are far more restrictive than those favoring high skew. Caste differentiation cannot be selected in saturated, symmetrical relatedness groups unless the genetic relatedness among group members is extremely high. In contrast, it can be selected in the saturated, asymmetrical relatedness (parent-offspring) groups with complete skew. If we also consider the future reproduction of subordinates, caste differentiation is possible only after the group size reaches a certain critical point. Most importantly, caste differentiation in a parent-offspring group increases its saturated group size. The positive feedback between group size and the degree of caste differentiation can continue in principle until completely sterile worker castes emerge. Thus, at least in the case of parent-offspring groups, group size but not the degree of reproductive skew may be a better index of the level of social complexity. A scheme for the evolution of sterile worker castes that integrates the role of group size into the framework of reproductive skew theory is proposed.

Animals↗
PubMed2004

Pre-social benefits of extended parental care.

The evolution of helping, in which some individuals forfeit their own reproduction and help others to reproduce, is a central problem in evolutionary biology. Recently proposed insurance-based mechanisms rely on a pre-existing life history with a long period of offspring dependency relative to the short life expectancies of adult carers: a lone mother's offspring are doomed if she dies young, whereas after a helper dies, other group members can finish rearing the offspring. A critical question, however, is how this life history could evolve in ancestral non-social populations, as offspring survival would then depend on a single, short-lived carer. Here, we resolve this paradox by focusing on the extended parental care inherent in prolonged dependency. We show experimentally that in non-social wasps, extended care can significantly reduce the impact of interspecific parasites. Under extended care, offspring are less vulnerable by the time they are exposed to parasites, and costs of parasitism are reduced because mothers have the option to terminate investment in failing offspring. By experimentally simulating aspects of extended care in a species where it is lacking, we demonstrate that neither benefit requires specialized behaviour. Such benefits could therefore offset the disadvantage of prolonged dependency in non-social species, thereby facilitating the evolution of helping.

Animals↗
PubMed2004

Tracing the evolution of brain and behavior using two related species of whiptail lizards: Cnemidophorus uniparens and Cnemidophorus inornatus.

Cnemidophorus whiptail lizards offer a unique opportunity to study behavioral and neural evolution because unlike most genera, ancestral and descendant species are still extant, and comparisons between species provide a window into correlated changes in biological organization through speciation. This review focuses on the all-female or parthenogenetic species Cnemidophorus uniparens (descendant species), which evolved through several hybridization events involving the sexually reproducing species Cnemidophorus inornatus (ancestral species). Data compiled over more than 2 decades include behavioral, endocrine, and neural differences between these two related species of whiptail lizards. For example, unlike females of the ancestral species, individuals of the descendant species display male-like mounting behavior (pseudocopulatory behavior) after ovulation. Pseudocopulatory behavior in the parthenogen is triggered by the progesterone surge after ovulation, and the behavioral capacity to respond to progesterone appears to be an ancestral trait that was inherited from C. inornatus males through the hybridization events. Interestingly, the regulation of sex steroid hormone receptor mRNA in brain areas critical for the expression of sociosexual behaviors differs between females of the two species and suggests that evolutionary changes in the regulation of gene expression could be a proximate mechanism that underlies the evolution of a novel social behavior in the parthenogen. Finally, because the sexual species is diploid, whereas the parthenogen is triploid, differences between the species could directly assess the effect of ploidy. The behavioral and neuroendocrinological data are pertinent for considering this possibility.

Animal Husbandry↗
PubMed1999

Prisoners of the proximate: loosening the constraints on epidemiology in an age of change.

"Modern epidemiology" has a primary orientation to the study of multiple risk factors for chronic noncommunicable diseases. If epidemiologists are to understand the determinants of population health in terms that extend beyond proximate, individual-level risk factors (and their biological mediators), they must learn to apply a social-ecologic systems perspective. The mind-set and methods of modern epidemiology entail the following four main constraints that limit engagement in issues of wider context: 1) a preoccupation with proximate risk factors; 2) a focus on individual-level versus population-level influences on health; 3) a typically modular (time-windowed) view of how individuals undergo changes in risk status (i.e., a life-stage vs. a life-course model of risk acquisition); and 4) the, as yet, unfamiliar challenge of scenario-based forecasting of health consequences of future, large-scale social and environmental changes. The evolution of the content and methods of epidemiology continues. Epidemiologists are gaining insights into the complex social and environmental systems that are the context for health and disease; thinking about population health in increasingly ecologic terms; developing dynamic, interactive, life-course models of disease risk acquisition; and extending their spatial-temporal frame of reference as they perceive the health risks posed by escalating human pressures on the wider environment. The constraints of "the proximate" upon epidemiology are thus loosening as the end of the century approaches.

Epidemiology↗
PubMed2005

Not in their genes: phenotypic flexibility, behavioural traditions and cultural evolution in wild bonnet macaques.

Phenotypic flexibility, or the within-genotype, context-dependent, variation in behaviour expressed by single reproductively mature individuals during their lifetimes, often impart a selective advantage to organisms and profoundly influence their survival and reproduction. Another phenomenon apparently not under direct genetic control is behavioural inheritance whereby higher animals are able to acquire information from the behaviour of others by social learning, and, through their own modified behaviour, transmit such information between individuals and across generations. Behavioural information transfer of this nature thus represents another form of inheritance that operates in many animals in tandem with the more basic genetic system. This paper examines the impact that phenotypic flexibility, behavioural inheritance and socially transmitted cultural traditions may have in shaping the structure and dynamics of a primate society--that of the bonnet macaque (Macaca radiata), a primate species endemic to peninsular India. Three principal issues are considered: the role of phenotypic flexibility in shaping social behaviour, the occurrence of individual behavioural traits leading to the establishment of social traditions, and the appearance of cultural evolution amidst such social traditions. Although more prolonged observations are required, these initial findings suggest that phenotypic plasticity, behavioural inheritance and cultural traditions may be much more widespread among primates than have previously been assumed but may have escaped attention due to a preoccupation with genetic inheritance in zoological thinking.

Animals↗
PubMed2005

Discrete hierarchical organization of social group sizes.

The 'social brain hypothesis' for the evolution of large brains in primates has led to evidence for the coevolution of neocortical size and social group sizes, suggesting that there is a cognitive constraint on group size that depends, in some way, on the volume of neural material available for processing and synthesizing information on social relationships. More recently, work on both human and non-human primates has suggested that social groups are often hierarchically structured. We combine data on human grouping patterns in a comprehensive and systematic study. Using fractal analysis, we identify, with high statistical confidence, a discrete hierarchy of group sizes with a preferred scaling ratio close to three: rather than a single or a continuous spectrum of group sizes, humans spontaneously form groups of preferred sizes organized in a geometrical series approximating 3-5, 9-15, 30-45, etc. Such discrete scale invariance could be related to that identified in signatures of herding behaviour in financial markets and might reflect a hierarchical processing of social nearness by human brains.

Anthropology, Cultural↗
PubMed2003

The critical role played by animal source foods in human (Homo) evolution.

Wild primates take most of the daily diet from plant sources, eating moderate to small amounts of animal source foods (ASF). Plant materials make up from 87% to >99% of the annual diet of great apes, the closest living relatives of modern humans (Homo sapiens sapiens). Reflecting their close genetic relationship, gut form and nutrient requirements of apes and humans (Hominoidea) are very similar, as is their pattern of digestive kinetics-one predicated on a relatively slow turnover of ingesta. In plant-eating mammals, in contrast to carnivorous mammals, greater body size is associated with lower dietary quality. Turning to ASF as a routine rather than occasional dietary component would have permitted the evolving human lineage to evade the nutritional constraints placed on body size increases in apes. Without routine access to ASF, it is highly unlikely that evolving humans could have achieved their unusually large and complex brain while simultaneously continuing their evolutionary trajectory as large, active and highly social primates. As human evolution progressed, young children in particular, with their rapidly expanding large brain and high metabolic and nutritional demands relative to adults would have benefited from volumetrically concentrated, high quality foods such as meat. Today, many humans, particularly those in high income nations, have a variety of high quality, non-ASF dietary alternatives, but such foods were not generally available to paleolithic human ancestors nor to many people today in low income nations.

Animals↗
PubMed1994

Social trajectories and diversity of careers: two aspects of the evolution of the medical profession in France (1925-1989).

Over the last 50 years or so, the medical profession has undergone a profound transformation. In France, the boundaries of this period are marked by two decisive factors: construction of a system of collective funding of the services offered to the public by the medical profession; the need to control the increasing cost of medical services. At the same time, the adoption of an organized and permissive approach to funding has created a protected market and greater medicalization of the different strata of society through a specific process of professionalization of medicine. We point out the implications of these processes. It is assumed that public funding has extended the scope of liberal medical practice without physicians themselves being fully aware of the advantages and the resulting economic benefits it has brought them, i.e. its effects in terms of easier acquisition of wealth. These assumptions are based on two aspects of the data collected in the course of an extensive survey of 5491 retired French doctors: 1. Analysis of data concerning the social origins and mobility of physicians. 2. Analysis of the medical careers of physicians, diversification of professional orientation over time and physicians' incomes.

Aged↗
PubMed1999

Male bonnet macaques use information about third-party rank relationships to recruit allies.

Social challenges may have driven the evolution of intelligence in primates and other taxa. In primates, the social intelligence hypothesis is supported by evidence that primates know a lot about their own relationships to others and also know something about the nature of relationships among other individuals (third-party relationships). Knowledge of third-party relationships is likely to play an especially important role in coalitions, which occur when one individual intervenes in an ongoing dispute involving other group members, by helping individuals to predict who will support or intervene against them when they are fighting with particular opponents, and to assess which potential allies are likely to be effective in coalitions against their opponents. To date, however, there is no evidence that primates make use of knowledge of third-party relationships when they form coalitions. Here, I show that male bonnet macaques, Macaca radiata, use information about third-party rank relationships when they recruit support from other males. Males consistently chose allies that outranked themselves and their opponents, and made such choices considerably more often than would be expected by chance alone. The analysis shows that the data do not fit simpler explanations based upon males' knowledge of their own relationships to other males or males' ability to recognize powerful allies. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗