Does morality have a biological basis? An empirical test of the factors governing moral sentiments relating to incest.

Kin-recognition systems have been hypothesized to exist in humans, and adaptively to regulate altruism and incest avoidance among close genetic kin. This latter function allows the architecture of the kin recognition system to be mapped by quantitatively matching individual variation in opposition to incest to individual variation in developmental parameters, such as family structure and co-residence patterns. Methodological difficulties that appear when subjects are asked to disclose incestuous inclinations can be circumvented by measuring their opposition to incest in third parties, i.e. morality. This method allows a direct test of Westermarck's original hypothesis that childhood co-residence with an opposite-sex individual predicts the strength of moral sentiments regarding third-party sibling incest. Results support Westermarck's hypothesis and the model of kin recognition that it implies. Co-residence duration objectively predicts genetic relatedness, making it a reliable cue to kinship. Co-residence duration predicts the strength of opposition to incest, even after controlling for relatedness and even when co-residing individuals are genetically unrelated. This undercuts kin-recognition models requiring matching to self (through, for example, major histocompatibility complex or phenotypic markers). Subjects' beliefs about relatedness had no effect after controlling for co-residence, indicating that systems regulating kin-relevant behaviours are non-conscious, and calibrated by co-residence, not belief.     

Beyond the Taboo: Imagining Incest

This article provides an overview of anthropology's 150-year discussion of the incest taboo in light of the last 30 years of feminist and psychoanalytic discoveries about the incestuous abuse of children, it invites anthropologists to explore incest ethnographically and offers three suggested ways: one biosocial, a second social relational, and a third psychoanalytic, focusing on a connection between what psychologists call dissociation and what anthropologists call trance or possession. [Key words: incest taboo, childhood sexual abuse, dissociation, trance/possession, innate avoidance mechanism]     

Intergenerational incest aversion: self-reported sexual arousal and disgust to hypothetical sexual contact with family members

The biological costs of inbreeding are expected to have shaped human incest aversion. These costs depend on biological sex, relatedness, and age. Whereas previous studies have focused on investigating how these factors modulate incest aversion in siblings and cousins—family members of the same generation— we examined relatives of different generations. In a population-based sample, 2499 respondents reported reactions to imagined sexual behaviors with either a biological child or parent, a niece/nephew or aunt/uncle, or a stepchild or stepparent; these responses were compared to reactions to imagined sexual behaviors involving a friend's child or parent. Replicating prior results, women report stronger incest aversions than do men. We extend previous findings by showing that incest aversions tended to be stronger between close (vs. more distant) intergenerational relatives. Indeed, for biological relatives, decreased degree of relatedness was associated with decreased incest aversion, and for biological relatives, the certainty in relatedness was also positively associated with incest aversion. As expected, age modulated sexual aversion for unrelated, but not related, target individuals. Sexual aversions towards step-relatives did not differ from sexual aversions to biological relatives.     

Survivre �� l��inceste : de l��adolescence �� l��age adulte. ��tude du cas d��un ��tudiant s��n��galais �� Dakar

The disclosure of incest is often difficult to accept. Denial or incredulity is common. Furthermore, attitudes to the consequences vary according to the period and the culture. The adverse effects of incest in children and young people could justify the prohibition of incest the world over. In this article, the authors report a case of a young student who consulted several health practitioners. Finally, he made a connection between his memories of incest with his grandmother and his failures in life. Recognition and long-term treatment of this sexual abuse within the family seem to be essential for the re-establishment of psychological development and social integration of this young man.     

Disappearance of the Incest Taboo: A Cross-Cultural Test of General Evolutionary Hypotheses

Employing a cross-cultural sample of 121 societies, this research tests and supports three hypotheses offered by Yehudi Cohen (1978) concerning the relationship between the general evolution of society and the extension of the incest taboo. Cohen generally proposes that the number of relatives included in the incest taboo will be reduced as societies become technologically and socially more complex. More specifically, Cohen identifies the development of trade institutions as eliminating the need for extended incest regulations. Furthermore, Cohen proposes that as the incest taboo contracts and becomes less important, violations of this taboo are treated less severely.     

The evolutionary significance of incest rules

Evolutionary theory predicts that humans should avoid incest because the behavior depresses individual fitness through production of defective offspring. Selection for avoidance of close-kin mating has resulted in a developmental mechanism that promotes voluntary incest avoidance. If avoided, why are social rules constructed in most cultures to regulate incest? The suggestion in this article is that incest do not regulate close-kin mating, but instead regulate inbreeding between more distant kin and sexual relations between nonkin. Inbreeding (e.g., cousin marriage) is hypothesized to be regulated because if it occurs, it can concentrate wealth and power within families threatening the powerful positions of rulers in the society. The hypothesis was supported using a worldwide sample of 129 societies, whereas two other alternative hypotheses (one dealing with coadapted genomes, and the other with sexual reproduction and host/ parasite coevolution), were not.     

Coming too Close,Going too Far: Theoretical and Cross‐cultural Approaches to Incest and its Prohibitions

Although interest in cultural explanations of topics like incest waned among Anglo anthropologists along with the abandonment of kinship theory in general, other paradigms provided a renewed interest in some older theories about the prohibition of incest. The approach presented in this paper gives due critical consideration to both evolutionary and ‘cultural’ explanations of incest and its prohibition suggesting their mutual involvement, but the necessity of a close analysis of the specificity of the cultural forms in which shared substance, connection, difference and nurture are expressed as reproductive ontology. Particular cases are discussed in the light of recent suggestions that the cross‐cultural incidence of incest and its prohibition is to be understood via theories of dissociative disorders in the West that allegedly illuminate a wide range of practices claimed to be linked to sexual abuse in childhood.     

Homosexual incest avoidance among females in captive Japanese macaques

This paper reports a systematic pattern of homosexual incest avoidance among females in a captive group of Japanese macaques (Macaca fuscata) culled from the Arashiyama-West troop known for its high rates of female homosexuality. The study group included three matrilines and two generations. Between eight and 11 females were sexually active over four consecutive mating seasons, and all engaged in both heterosexual and homosexual activity. While all females performed homosexual acts with almost all possible non-kin partners, they systematically avoided homosexual interactions with their mother, daughters, and sisters. This pattern could not be explained either in terms of kin not being simultaneously in estrus, kin avoiding affiliative interactions in general, or non-kin utilizing the tension-reducing effect of estrus to affiliate exclusively with each other. In contrast to homosexual females, heterosexual pairs of relatives (brother-sister, mother-son) were sometimes incestuous. Assuming that female homosexuality expresses the reproductive strategy of females unconstrained by male influence, the present results point to the strong tendency of females to avoid incest and suggest that males are primarily responsible for the reported exceptions to incest avoidance.     

Childhood Association and Sexual Attraction: A Further Test of the Westermarck Hypothesis

A preliminary study of household registration records from Taiwan supports Edward Westermarck's contention that intimate childhood association promotes sexual aversion. Women who are forced to marry a childhood associate bear fewer children than those who marry a stranger. They are also more likely to leave their husband by divorce or avoid him in favor of other men. This evidence suggests that the incest taboo does not prohibit what men's feelings incline them to do, as Westermarck's critics argue, but that it is instead an expression of these feelings, socially unnecessary but psychologically inevitable. [incest taboo, law, China, Taiwan]     

FBD Marriage: Further Support for the Westermarck Hypothesis of the Incest Taboo?

In the past decade, several reports, including data from Taiwan on the sim-pua form of marriage, have provided evidence for the Westermarck Hypothesis, a heretofore unpopular explanation of the incest taboo. This theory states that intimate childhood association breeds sexual disinterest. A preliminary study of FBD marriage in Lebanon reveals similar support for Westermarck's theory. The Lebanese patrilateral parallel cousin marriages examined produced significantly fewer children and more divorces than nonpaternal first cousin unions. Given the quite disparate cultures from which this evidence comes, serious reconsideration of Westermarck's Hypothesis is suggested. [incest taboo, FBD marriage, Lebanon, Middle Eastern sexuality]     

Causes and consequences of incest avoidance in the cooperatively breeding mole-rat, Cryptomys darlingi (Bathyergidae)

A number of social mole-rat species maintain a strong reproductive skew (only one breeding pair in the group) solely through incest avoidance. Incest avoidance probably evolved for one of two reasons, namely for actually maintaining a reproductive skew or, alternatively, to avoid high inbreeding depression. In the latter case a strong reproductive skew would result as a fortuitous by-product of the combination of a cloistral family life style of mole-rats and incest avoidance. We undertook breeding experiments in which the fertility of pairs of unrelated individuals were compared with that of pairs of double first cousins. Inbreeding depression was remarkably high and an accompanying model suggests that it may be sufficient to support the idea that strong incest avoidance evolved primarily to eliminate the costs of inbreeding and subsequently facilitated the evolution of reproductive skew.     

Trace and mineral elements in royal jelly and homeostatic effects

Royal jelly from Apis mellifera is a highly active natural biological substance and is probably one of the most interesting raw substances in natural product chemistry. Trace elements play a key role in the biomedical activities associated with royal jelly, as these elements have a multitude of known and unknown biological functions. For this reason concentrations of 28 trace (Al, Ba, Sr, Bi, Cd, Hg, Pb, Sn, Te, Tl, W, Sb, Cr, Ni, Ti, V, Co, Mo) and mineral (P, S, Ca, Mg, K, Na, Zn, Fe, Cu, Mn) elements were systematically investigated in botanically and geologically defined royal jelly samples. In addition, concentrations of 14 trace elements were measured in the associated honey samples--honey being the precursor of royal jelly. Concentrations of K, Na, Mg, Ca, P, S, Cu, Fe, Zn, Al, Ba and Sr in royal jelly were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES), while concentrations of Bi, Cd, Hg, Pb, Sn, Te, Tl, W, Sb, Cr, Mn, Ni, Ti, V, Co and Mo in royal jelly were determined by double focusing magnetic sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). In the honey samples, trace and mineral element concentrations strongly depended on botanical and geological origin, and substantial variation was found. In contrast, the concentrations of trace and mineral elements were highly constant in the associated royal jelly samples. The most important results were the homeostatic adjustments of trace and mineral element concentrations in royal jelly. This effect was evidently produced in the endocrine glands of nurse bees, which are adapted for needs of bee larvae. In conclusion, this research yielded a surprising and completely new finding--that royal jelly, as a form of lactation on the insect level, shows the same homeostatic adjustment as mammalian and human breast milk.     

Ethanol‐soluble proteins from the royal jelly of Xinjiang black bees

Royal jelly is a nutritious food that has beneficial effects to human health. However, the functional substances remain unclear. Herein, we fractioned the royal jelly proteins of Xinjing black bees according to the Osboren method. Two main proteins from the ethanol‐soluble fraction were purified and identified. RJG‐1 was determined as glucosylceramidase, and RJG‐2 was major royal jelly protein 1 (MRJP1). RJG‐1 showed potent cytotoxicity toward various mammalian cells, and caused quick disruption of cell membranes. With glucosylceramidase activity, RJG‐1 may degrade the glucosylceramide of the cell membranes and disrupt the membrane structure, thereby resulting in cell necrosis. This study extends our knowledge about the composition and function of royal jelly, and is significant for the application of royal jelly.     

意大利蜂营养腺的形态结构研究

研究了意大利蜂分泌蜂王浆的主要腺体──营养腺的形态结构及腺体随工蜂日龄增加而变化的规律。结果表明,工蜂羽化后,在各个日龄段随其职能分工的不同,营养腺形态结构也有相应的变化。从羽化出房的幼峰到哺育蜂到采集蜂,其营养腺要经历发育─→饱满发达─→衰退萎缩的过程。分泌细胞中的粗面内质网变化更为明显。     

Reproductive roles in the cooperatively breeding acorn woodpecker: incest avoidance versus reproductive competition

Incest is rare in the cooperatively breeding acorn woodpecker (Melanerpes formicivorus) despite a polygynandrous mating system in which nearly all group members are close relatives. Here we test the relative importance of avoiding matings between close relatives (incest avoidance) and within-sex competition for breeding opportunities (reproductive competition) in determining the mating system of acorn woodpeckers by examining how reproductive roles change following breeding vacancies. In 83% of cases in which helpers of the same sex were present in the group, reproductive vacancies were resolved when new unrelated immigrants filled the vacancy to the exclusion of resident same-sex helpers, who generally emigrated or did not breed while they remained in the group. Helpers of the opposite sex, especially when male, were significantly more likely to remain in their natal group and in about half the cases inherited and bred following reproductive vacancies. This result was not explainable by reproductive competition, since the number of immigrants was often less than or equal to the number of same-sex helpers in the group. Apparent incest resulted in 5% of cases. The time required to resolve reproductive vacancies was significantly longer for groups with helpers of the same sex as the vacancy. These results confirm that both incest avoidance and reproductive competition are important factors determining reproductive roles within groups of this highly social species.     

Adopt a Daughter-in-Law, Marry a Sister: A Chinese Solution to the Problem of the Incest Taboo

In stressing the social advantages of the familial incest taboo, most explanations of the taboo ignore the fact that it makes marriage the enemy of the family. The stranger intruded by marriage often poses a threat to existing domestic relationships. The Chinese solution to this problem is to circumvent the taboo by adopting female children who are raised as wives for their foster parents' sons. The family choosing this form of marriage sacrifices prestige and dependable affinal ties, but by socializing their own daughters-in-law they preserve domestic harmony. The fact that many Chinese arrange marriages within the family as a means of preserving the family suggests that widely accepted explanations of the incest taboo exaggerate the dangers of incest and ignore the dangers of the taboo.     

The Precultural Basis of the Incest Taboo: Toward a Biosocial Theory

The literature on the origins of the incest taboo is characterized by controversy over the nature/nurture issue, and fears of reductionism. In recent years work emanating from such diverse disciplines as cultuml and physical anthropology, ethology, and neuropsychology warmnts a new look at this intriguing issue. It is probable that incest avoidance is widespread among the vertebrata and is "built into the wiring." As learned behavior becomes more important phylogenetically, curiosity and exploration plays a larger role in adaptation and has manifest survival admntages. Incest awidance functions as a mechanism to propel the individual into new relationships and "social territory." For humans, incest avoidance and its later elaboration into a cultuml taboo serve to motivate exploration of and attachment to a wider social nexus than the family. It also prevents fixation at a relatively undifferentiated psychological stage of development