The evolution of matrilineal kinship organization

Matrilineal kinship organization is a human social system that emphasizes interactions between matrilineal kin, i.e. individuals related only through females. The ‘matrilineal puzzle’ refers to the potential for tension characteristic of this social system, owing to the conflict between the interests and responsibilities of men in their roles as brother/uncle versus husband/father. From an evolutionary perspective, matrilineal kinship organization is puzzling when it diverts investment of resources from the individuals who provide the potentially highest reproductive returns. I use a game-theoretic framework to investigate a particular form of matrilineal inheritance—the transfer of property from a maternal uncle to a sororal nephew. The analysis reveals two mechanisms that may make this strategy a stable evolutionary outcome. First, a polygynous male has multiple wives, and hence multiple brothers-in-law; with matrilineal inheritance, each additional brother-in-law may transfer resources to the male''s wife''s offspring, thus potentially contributing to the male''s inclusive fitness. Second, the husband of a polyandrous female is effectively ‘sharing’ paternity with other men; depending on the number of husbands, he may be better off investing in his sister''s offspring. I conclude by discussing how these results address the challenges posed by the occurrence of matrilineal kinship organization.     

Matriliny as daughter-biased investment

From an evolutionary perspective, matriliny presents a puzzle because men in matrilineal societies transmit wealth to their sisters' sons, to whom they are only half as related as to their own sons. It has been argued that such systems would only maximise fitness under unrealistically high levels of paternity uncertainty. In this paper, we propose that matriliny can arise from daughter-biased investment by parents and/or grandparents. We show that daughter-biased investment is adaptive if the marginal benefit of wealth to sons (compared to daughters) does not outweigh the risk of nonpaternity in sons' offspring. We argue that such conditions will be rare where resource-holding polygyny is prevalent but could otherwise be widespread under even moderate levels of paternity uncertainty. The daughter-biased investment model explains two well-known characteristics of matrilineal descent: (a) matriliny's association with high levels of paternity uncertainty and (b) matriliny's ecological correlates, including its association with horticulture, its rarity in pastoralist and agro-pastoralist societies, and the tendency for matriliny to be replaced by son-biased inheritance during economic development. We present data on wealth, sex, and reproductive success (RS) in two African societies, the matrilineal Chewa in Malawi and patrilineal Gabbra in Kenya, which support the daughter-biased investment theory.     

Spread of cattle led to the loss of matrilineal descent in Africa: a coevolutionary analysis

Matrilineal descent is rare in human societies that keep large livestock. However, this negative correlation does not provide reliable evidence that livestock and descent rules are functionally related, because human cultures are not statistically independent owing to their historical relationships (Galton''s problem). We tested the hypothesis that when matrilineal cultures acquire cattle they become patrilineal using a sample of 68 Bantu- and Bantoid-speaking populations from sub-Saharan Africa. We used a phylogenetic comparative method to control for Galton''s problem, and a maximum-parsimony Bantu language tree as a model of population history. We tested for coevolution between cattle and descent. We also tested the direction of cultural evolution--were cattle acquired before matriliny was lost? The results support the hypothesis that acquiring cattle led formerly matrilineal Bantu-speaking cultures to change to patrilineal or mixed descent. We discuss possible reasons for matriliny''s association with horticulture and its rarity in pastoralist societies. We outline the daughter-biased parental investment hypothesis for matriliny, which is supported by data on sex, wealth and reproductive success from two African societies, the matrilineal Chewa in Malawi and the patrilineal Gabbra in Kenya.     

Refusing to Sing: Gender,Kinship and Patriliny in Macedonia

The issue of whether formal kinship structures and sentiments reflect the reality of social relations was of particular concern to specialists at the height of the kinship debates in the 1960s and 1970s, as it continues to be in some contemporary studies. So too, the classifications ‘patrilineal’ or ‘matrilineal’ have clearly been shown to be problematic given that there are multiple levels of discourse and relational and ideational realities in any given society. For many contemporary kinship specialists in fact no simple correlation can be made between type of descent system and actual social relations, especially relations between men and women. However, some anthropologists continue to argue that patrilineal kinship systems are somehow indicative of control or domination by men or, put inversely, of women's lack of power and authority. It is argued in this paper that even where the formal kinship structures and ideological discourses are dominated by agnation as appears to be the case in south Slav societies generally, and Macedonian in particular, this is not automatically mirrored in gender relations between men and women. In short, there is a long leap from patriliny to patriarchy.     

Avoidance of close consanguineous inbreeding in captive groups of rhesus macaques

In three captive groups of rhesus macaques (Macaca mulatto) the intensity of inbreeding avoidance was directly correlated with the closeness of kinship. The incidence of inbreeding between matrilineal relatives was lower than expected were mating to occur randomly with regard to matrilineal affiliation. The avoidance of mating between sons and their mothers and between matrilineal sibs contributed about squally to this outcome. The incidence of mating between more remote matrilineal relatives was lower than, but could not be shown to differ significantly from, that expected at the 0.05 level of probability. Familiarity fostered by interactions among matriline members probably provides a focus for avoidance of matrilineal inbreeding, and might influence male dispersal. Results of this study are consistent with reports of female rhesus macaques' avoidance of sexual activity with matrilineal male relatives as predicted by parental investment theory The observed incidence of inbreeding between patrilineal relatives was not different from that expected, but significantly fewer of the patrilineally inbred matings involved father/daughter matings than expected were mating random. Recognition of phenotypic similarities might provide a focus for avoidance of inbreeding between fathers and their daughters, but is loss reliable than strategies for avoiding matrilineal inbreeding. Adaptations for avoiding matrilineal inbreeding that are more effective than those for avoiding patrilineal inbreeding might have evolved because the risk of patrilineal inbreeding, and hence the resulting loss in fitness, is marginal compared to that for matrilineal inbreeding in free-ranging groups. © 1995 Wiley-Liss, Inc.     

The Development of Higher Forms of Attention in Childhood

The history of attention in the child is the history of levels of the organization of his/her behavior. This history begins from the very moment of birth. Initially the child's attentional processes are carried out through inherited neurological mechanisms that organize the functioning of his/her reflexes in accordance with the well-known physiological principle of response dominance. This principle asserts that the organizing feature in the nervous system is a single, supreme center of stimulation whose strength grows at the expense of these inherited mechanisms. The dominant response provides the organic basis of the behavioral processes referred to as attention.     

Behavior of an all-juvenile group of Rhesus monkeys

The behavior and organization of a group of 33 juvenile rhesus monkeys removed from a single free-ranging group were found to parallel closely intact rhesus social groups. Dominance ranking among the juveniles was 95% predictable from prior knowledge of mothers' ranks. Grooming, sitting close together, sitting touching, and play were found to occur much more frequently between matrilineal kin than expected from random selection of partner. Some estrous behavior was observed, including two instances of peri-menstrual estrus. One lengthy homosexual interaction between two two-year-old females was observed. The basis of much of the behavior and organization shown by the juveniles was found to be the matrilineal kin bonds brought from their natal group.     

Linnaeus's natural and artificial arrangements of plants

Linnaeus's artificial and natural arrangements of plants are examined using a Spearman rank coefficient (which is explained) on his presentations of his own and others' arrangements in the Classes plantarum and elsewhere. There is little alteration in his successive artificial arrangements. In contrast, between 1751 and 1764 his natural arrangements changed considerably, partly in the sequences of genera within orders but mostly by rearrangement of the orders. Comparison with Cesalpino's and Ray's natural arrangements, using the longest-recognized natural groups as signposts, suggests that Linnaeus in his latest natural arrangement (1764) approximated more closely to Ray's. Examination of Linnaeus's successive treatments of certain groups (palms, Zingiberaceae, Hydrocharis-Stratiotes-Vallisneria) and of Giseke's exposition of Linnaeus's lectures on natural groups (1792) shows that Linnaeus was much influenced by habitus and vegetative characters as well as those of the fructification. He recognized orders consisting of a chain of genera linked successively by overall affinity and without any single diagnostic character. Where possible, he preferred characters of the fructification and his ‘secret’ consulting of the habitus is explained as secondary to such characters. It is suggested that in his latest arrangement he approximated more to a scala naturae, as he probably did in zoology about the same time. Within his artificial arrangements Linnaeus kept to sequences of genera as natural as possible. He realized that some groups in his natural arrangements were still artificial, and his aphorism that all genera and species are natural, classes and orders part natural and part artificial, refers to his and others' practice until the natural system could be completed. It is not a statement of the essential natures of these ranks. Linnaeus's distinction in practice between natural and artificial arrangements was less clear-cut than Sachs believed. Linnaeus's rejection of the ancient tree/herb division was empirical, not a reasoned repudiation of an a priori grouping. The tree/herb division could be upheld in his day as obviously natural, not merely accepted on authority.     

Detecting instability in animal social networks: genetic fragmentation is associated with social instability in rhesus macaques

The persistence of biological systems requires evolved mechanisms which promote stability. Cohesive primate social groups are one example of stable biological systems, which persist in spite of regular conflict. We suggest that genetic relatedness and its associated kinship structure are a potential source of stability in primate social groups as kinship structure is an important organizing principle in many animal societies. We investigated the effect of average genetic relatedness per matrilineal family on the stability of matrilineal grooming and agonistic interactions in 48 matrilines from seven captive groups of rhesus macaques. Matrilines with low average genetic relatedness show increased family-level instability such as: more sub-grouping in their matrilineal groom network, more frequent fighting with kin, and higher rates of wounding. Family-level instability in multiple matrilines within a group is further associated with group-level instability such as increased wounding. Stability appears to arise from the presence of clear matrilineal structure in the rhesus macaque group hierarchy, which is derived from cohesion among kin in their affiliative and agonistic interactions with each other. We conclude that genetic relatedness and kinship structure are an important source of group stability in animal societies, particularly when dominance and/or affilative interactions are typically governed by kinship.     

"I won't do surgery if you don't try to do my job," head of new blood agency tells MDs

Ken Fyke is known as a tough administrator, and he is going to need all of his administrative tricks as first chair of Canadian Blood Services, the new national organization that is taking over responsibility for the nation''s blood supply from the Red Cross come September. Fyke says he hopes to work closely with physicians, but they will have to realize where their responsibilities end and his begin.     

Socio-genetic structure and mating system of a wild boar population

Wild boars Sus scrofa have a social organization based on female groups that can include several generations of adults and offspring, and are thus likely matrilineal. However, little is known about the degree of relatedness between animals living in such groups or occupying the same core area of spatial activity. Also, polygynous male mating combined with matrilineal female groups can have strong influences on the genetic structure of populations. We used microsatellite genotyping combined with behavioral data to investigate the fine-scale population genetic structure and the mating system of wild boars in a multi-year study at Châteauvillain-Arc-en-Barrois (France). According to spatial genetic autocorrelation, females in spatial proximity were significantly inter-related. However, we found that numerous males contributed to the next generation, even within the same social group. Based on our genetic data and behavioral observations, wild boars in this population appear to have a low level of polygyny associated with matrilineal female groups, and infrequent multiple paternity. Mortality due to hunting may facilitate the breakup of what historically has been a more predominantly polygynous mating system, and likely accelerates the turnover of adults within the matrilineal groups.     

Hans van Houwelingen and the Art of Summing up

Some personal remarks about Hans van Houwelingen's approach to biostatistics in general are followed by a discussion of his article with Koos Zwinderman and Theo Stijnen outlining a bivariate approach to meta‐analysis. It is concluded that this is more radical than many may realise in that it permits inter‐trial information to be recovered. This has some advantages but in theory opens the door to bias. It is concluded that in practice the size of this bias is likely to be small. I end with some further personal remarks to Hans.     

Postmarital residence and biological variation at Pueblo Bonito

Although the social organization of many of the present-day pueblos of the American Southwest is well-described in the anthropological literature, many aspects of prehistoric Puebloan social organization have received limited attention since initial investigations of postmarital residence in the 1960s and 1970s. This paper examines postmarital residence at the Chaco Canyon great house of Pueblo Bonito, using biological data. Our findings are inconsistent with the previously well-accepted hypothesis that the Pueblo II and Pueblo III occupants of the San Juan Basin conformed to a socially prescribed pattern of matrilocal residence with matrilineal descent. Univariate variance differences for nine craniometric variables indicate a pattern of increased female variability consistent with patrilocal/bilocal residence. The results of multivariate determinant ratio analyses are in agreement with the univariate results, suggesting the possibility of a patrilocal or bilocal residence preference at Pueblo Bonito. These findings are inconsistent with the notion that the female-based system of matrilocal residence with matrilineal descent observed among the present-day Western Pueblos was the ancestral Anasazi condition.     

Which Is the Most Suitable Classification for Colorectal Cancer,Log Odds,the Number or the Ratio of Positive Lymph Nodes?

Objective

The aim of the current study was to investigate which is the most suitable classification for colorectal cancer, log odds of positive lymph nodes (LODDS) classification or the classifications based on the number of positive lymph nodes (pN) and positive lymph node ratio(LNR) in a Chinese single institutional population.

Design

Clinicopathologic and prognostic data of 1297 patients with colorectal cancer were retrospectively studied. The log-rank statistics, Cox''s proportional hazards model, the Nagelkerke R² index and a Harrell''s C statistic were used.

Results

Univariate and three-step multivariate analyses identified that LNR was a significant prognostic factor and LNR classification was superior to both the pN and LODDS classifications. Moreover, the results of the Nagelkerke R² index (0.130) and a Harrell''s C statistic (0.707) of LNR showed that LNR and LODDS classifications were similar and LNR was a little better than the other two classifications. Furthermore, for patients in each LNR classification, prognosis was homologous between those in different pN or LODDS classifications. However, for patients in pN1a, pN1b, LODDS2 and LODDS3 classifications, significant differences in survival were observed among patients in different LNR classifications.

Conclusions

For patients with colorectal cancer, the LNR classification is more suitable than pN and LODDS classifications for prognostic assessment in a Chinese single institutional population.     

Longitudinal study of dominance relations among captive patas monkeys

Eight and a half years of dominance relations within a captive group of patas monkeys were analyzed. It was found that matrilineal kinship significantly influenced individuals' ranks. In contrast, with the exception of certain intramatriline changes, increasing age had no predictable effect on overall rank, at least for females (this was untestable for males). Offspring typically challenged maternal dominance and in eight of twelve dyads, offspring either rose fully over their mothers (three cases, all daughters) or at least achieved dominance ambiguity with them. Additionally, two of the four younger sisters with an opportunity to rise in rank over an older sister did so. The group dominance hierarchy was unstable for 75% of the study due to a combination of agonistically induced and demographically induced rank changes. Concentration of the highest ranks in a single matriline showed a stronger association with group hierarchy stability than did the presence of an adult, nonnatal male. Group hierarchy stability was associated with increased affiliation (sitting close and sitting touching), but otherwise there were no behavioral correlations. Individuals' ranks within the group hierarchy were unrelated to their chances of being wounded or having diarrhea. Adult females' ranks were over twice as stable as the group hierarchy (57.1% stability), but stability/instability was not correlated with any behavioral changes. Available evidence suggests that dominance relations play only a minor role in the organization of patas monkeys' intragroup behavior. Am. J. Primatol. 42:41–51, 1997. © 1997 Wiley-Liss, Inc.     

A different contender? Barack Obama,the 2008 presidential campaign and the racial politics of sport

Abstract

This paper explores popular representations of Barack Obama's relationship to sport during the 2008 US presidential campaign. It delineates how white normativity framed the candidate's passion for basketball and his participation in a highly publicized bowling game. We argue that Obama's athletic activities became key vehicles for reading his body and by extension his identity and his politics. The question that could only be asked in a white supremacist context – is Obama too black or not black enough to be President? – mirrored long-standing tensions in America's affective relation to black male athletes. Representations of Obama bowling further illuminate the complicated ways in which whiteness operates. The essay concludes with a brief discussion suggesting the importance of analyses of sport for ethnic and racial studies.     

Alliance formation in a free-ranging troop of Japanese macaques

Alliance formations in a troop of free-ranging Japanese macaques, which had been provisioned 16 months before the present study was begun, were observed at the feeding ground for about 300 hr from April 1973 to March 1974. The patterns of alliance formations and their roles were described. The leader male had a quite unique role in his alliance formations; he allied much frequently with the aggressees and attacked the aggressors. Besides, the leader male allied more frequently with babies, yearlings, 2-year-old animals, and adult females, while he frequently attacked the 3- and 4-year-old animals and adult males. The animals who belonged to the same matrilineal group always allied with one another. Except the leader male, the troop members rather preferred to ally, except in those cases where the former diads involved their matrilineal group members, with the first aggressors. Networks of such alliance formations in relation with the social organization of Japanese macaques are discussed.     

Sexual selection: Another Darwinian process

Why was sexual selection so important to Darwin? And why was it de-emphasized by almost all of Darwin's followers until the second half of the 20th century? These two questions shed light on the complexity of the scientific tradition named “Darwinism”. Darwin's interest in sexual selection was almost as old as his discovery of the principle of natural selection. From the beginning, sexual selection was just another “natural means of selection”, although different from standard “natural selection” in its mechanism. But it took Darwin 30 years to fully develop his theory, from the early notebooks to the 1871 book The Descent of Man, and Selection in Relation to Sex. Although there is a remarkable continuity in his basic ideas about sexual selection, he emphasized increasingly the idea that sexual selection could oppose the action of natural selection and be non adaptive. In time, he also gave more weight to mate choice (especially female choice), giving explicit arguments in favor of psychological notions such as “choice” and “aesthetic sense”. But he also argued that there was no strict demarcation line between natural and sexual selection, a major difficulty of the theory from the beginning. Female choice was the main reason why Alfred Russel Wallace, the co-discoverer of the principle of natural selection, engaged in a major controversy with Darwin about sexual selection. Wallace was suspicious about sexual selection in general, trying to minimize it by all sorts of arguments. And he denied entirely the existence of female choice, because he thought that it was both unnecessary and an anthropomorphic notion. This had something to do with his spiritualist convictions, but also with his conception of natural selection as a sufficient principle for the evolutionary explanation of all biological phenomena (except for the origin of mind). This is why Wallace proposed to redefine Darwinism in a way that excluded Darwin's principle of sexual selection. The main result of the Darwin–Wallace controversy was that most Darwinian biologists avoided the subject of sexual selection until at least the 1950 s, Ronald Fisher being a major exception. This controversy still deserves attention from modern evolutionary biologists, because the modern approach inherits from both Darwin and Wallace. The modern approach tends to present sexual selection as a special aspect of the theory of natural selection, although it also recognizes the big difficulties resulting from the inevitable interaction between these two natural processes of selection. And contra Wallace, it considers mate choice as a major process that deserves a proper evolutionary treatment. The paper's conclusion explains why sexual selection can be taken as a test case for a proper assessment of “Darwinism” as a scientific tradition. Darwin's and Wallace's attitudes towards sexual selection reveal two different interpretations of the principle of natural selection: Wallace's had an environmentalist conception of natural selection, whereas Darwin was primarily sensitive to the element of competition involved in the intimate mechanism of any natural process of selection. Sexual selection, which can lack adaptive significance, reveals this exemplarily.