An evolutionary analysis of psychological pain following rape:: II. The effects of stranger,friend, and family-member offenders

In earlier papers we discussed a hypothesis for the evolutionary significance of psychological pain. In the present paper we discuss briefly the hypothesis and its application to the psychological pain experienced by rape victims. We have hypothesized that psychological pain reflects a psychological adaptation that is designed to focus on individual's full attention on fitness-reducing social circumstances, allowing correction of the pain causing events and their future avoidance. Psychological pain following rape is proposed to accomplish a focus of victims' attention on the fitness reducing circumstances of rape. Using a data-set comprised of 790 rape victims in the U.S. whose post-rape psychological trauma was assessed, we evaluate the effects of rape by strangers, friends and family members. The victims in the sample are most likely to be raped by strangers; this is especially the case for women as opposed to prereproductive-aged girls. Prereproductive-aged girls were more likely to be raped by family members than were women. Rape by strangers is the most psychologically traumatizing of the three rape-offender categories and family-member rape the least. The importance of victim's age and marital status as predictive factors in the degree of psychological trauma following rape—with reproductive-aged and married victims showing significantly more trauma than pre- or post-reproductive-aged and unmarried victims (see N.W. Thornhill and R. Thornhill 1990)—is not confounded by the type of rape perpetrator.     

Wing morphology of the butterfly Coenonympha arcania in Europe: Traces of both historical isolation in glacial refugia and current adaptation

In this study, we examined the evolutionary outcome of and interplay between historic isolation and current selection pressures on traits more or less closely connected to fitness in the Pearly Heath butterfly (Coenonympha arcania) across its range in Europe. We hypothesized that a trait mean is more related to historic events if it has low connection to fitness, while a trait more closely connected with fitness is expected to have a mean that relates more to current selection pressures. In order to test this, we collected 322 butterflies from across the species range in Europe and measured five wing traits relating to size and color patterns. To infer a phylogeographic history for each individual, we sequenced a 594 bp fragment of the COI gene. The morphological data were then analyzed in relation to selected climatic variables and the history of individuals to disentangle which factors best correlated with morphological variation. The results supported our hypothesis in that wing sizes correlated with summer precipitation but not with its inferred location during the last glaciation. Eyespot position, on the other hand, correlated with the history of individuals but not with the analyzed climatic indicators. The sizes of the black spot and the white band, two traits that were expected to have intermediate selection pressure, were associated with both history and current conditions. Thus, this study illustrates the fascinating interplay between events and processes that lead to a specific evolutionary outcome.     

Evolutionary psychiatry: foundations,progress and challenges

Evolutionary biology provides a crucial foundation for medicine and behavioral science that has been missing from psychiatry. Its absence helps to explain slow progress; its advent promises major advances. Instead of offering a new kind of treatment, evolutionary psychiatry provides a scientific foundation useful for all kinds of treatment. It expands the search for causes from mechanistic explanations for disease in some individuals to evolutionary explanations for traits that make all members of a species vulnerable to disease. For instance, capacities for symptoms such as pain, cough, anxiety and low mood are universal because they are useful in certain situations. Failing to recognize the utility of anxiety and low mood is at the root of many problems in psychiatry. Determining if an emotion is normal and if it is useful requires understanding an individual's life situation. Conducting a review of social systems, parallel to the review of systems in the rest of medicine, can help achieve that understanding. Coping with substance abuse is advanced by acknowledging how substances available in modern environments hijack chemically mediated learning mechanisms. Understanding why eating spirals out of control in modern environments is aided by recognizing the motivations for caloric restriction and how it arouses famine protection mechanisms that induce binge eating. Finally, explaining the persistence of alleles that cause serious mental disorders requires evolutionary explanations of why some systems are intrinsically vulnerable to failure. The thrill of finding functions for apparent diseases is evolutionary psychiatry's greatest strength and weakness. Recognizing bad feelings as evolved adaptations corrects psychiatry's pervasive mistake of viewing all symptoms as if they were disease manifestations. However, viewing diseases such as panic disorder, melancholia and schizophrenia as if they are adaptations is an equally serious mistake in evolutionary psychiatry. Progress will come from framing and testing specific hypotheses about why natural selection left us vulnerable to mental disorders. The efforts of many people over many years will be needed before we will know if evolutionary biology can provide a new paradigm for understanding and treating mental disorders.     

动物生活史进化理论研究进展

综述了生活史性状、生活史对策、权衡、适合度及进化种群统计学等动物生活史进化领域的进展。权衡是生活史性状之间相互联系的纽带,分为生理权衡与进化权衡。适合度是相对的,与个体所处的特定环境条件有关,性状进化与适合度之间关系紧密。适合度是生活史进化理论研究的焦点。探讨动物生活史对策的理论很多,影响最大的是MacArthur和Wilson提出的r对策及K对策理论。随年龄的增长,动物存活率及繁殖率逐步下降的过程,称为衰老;解释衰老的进化理论主要有突变-选择平衡假设和多效对抗假设。进化种群统计学将种群统计学应用于生活史进化研究,为探讨表型适合度的进化提供了有效的手段。将进化种群统计学、数量遗传学及特定种系效应理论进行整合,建立完整的动物生活史进化综合理论体系,是当代此领域的最大挑战。     

Sexual coercion and forced in-pair copulation as sperm competition tactics in humans

Rape of women by men might be generated either by a specialized rape adaptation or as a by-product of other psychological adaptations. Although increasing number of sexual partners is a proposed benefit of rape according to the “rape as an adaptation” and the “rape as a by-product” hypotheses, neither hypothesis addresses directly why some men rape their long-term partners, to whom they already have sexual access. In two studies we tested specific hypotheses derived from the general hypothesis that sexual coercion in the context of an intimate relationship may function as a sperm competition tactic. We hypothesized that men’s sexual coercion in the context of an intimate relationship is related positively to his partner’s perceived infidelities and that men’s sexual coercion is related positively to their mate retention behaviors (behaviors designed to prevent a partner’s infidelity). The results from Study 1 (self-reports from 246 men) and Study 2 (partner-reports from 276 women) supported the hypotheses. The Discussion section addresses limitations of this research and highlights future directions for research on sexual coercion in intimate relationships.     

Phylogenetic effects on functional traits and life history strategies of Australian freshwater fish

Understanding the biogeographic and phylogenetic basis to interspecific differences in species’ functional traits is a central goal of evolutionary biology and community ecology. We quantify the extent of phylogenetic influence on functional traits and life‐history strategies of Australian freshwater fish to highlight intercontinental differences as a result of Australia's unique biogeographic and evolutionary history. We assembled data on life history, morphological and ecological traits from published sources for 194 Australian freshwater species. Interspecific variation among species could be described by a specialist–generalist gradient of variation in life‐history strategies associated with spawning frequency, fecundity and spawning migration. In general, Australian fish showed an affinity for life‐history strategies that maximise fitness in hydrologically unpredictable environments. We also observed differences in trait lability between and within life history, morphological and ecological traits where in general morphological and ecological traits were more labile. Our results showed that life‐history strategies are relatively evolutionarily labile and species have potentially evolved or colonised in freshwaters frequently and independently allowing them to maximise population performance in a range of environments. In addition, reproductive guild membership showed strong phylogenetic constraint indicating that evolutionary history is an important component influencing the range and distribution of reproductive strategies in extant species assemblages. For Australian freshwater fish, biogeographic and phylogenetic history contribute to broad taxonomic differences in species functional traits, while finer scale ecological processes contribute to interspecific differences in smaller taxonomic units. These results suggest that the lability or phylogenetic relatedness of different functional traits affects their suitability for testing hypothesis surrounding community level responses to environmental change.     

Physically strong men are more militant: A test across four countries

There is substantial evidence from archaeology, anthropology, primatology, and psychology indicating that humans have a long evolutionary history of war. Natural selection, therefore, should have designed mental adaptations for making decisions about war. These adaptations evolved in past environments, and so they may respond to variables that were ancestrally relevant but not relevant in modern war. For example, ancestrally in small-scale combat, a skilled fighter would be more likely to survive a war and bring his side to victory. This ancestral regularity would have left its mark on modern men's intergroup psychology: more formidable men should still be more supportive of war. We test this hypothesis in four countries: Argentina, Denmark, Israel, and Romania. In three, physically strong men (but not strong women) were significantly more supportive of military action. These findings support the hypothesis that modern warfare is influenced by a psychology designed for ancestral war.     

Human kin recognition is self- rather than family-referential

Inclusive fitness theory predicts that organisms will tend to help close kin more than less related individuals. In a variety of birds and mammals, relatives are recognized by comparing their phenotype to an internal representation or template, which might be learned through either repeated exposure to family members or self-inspection. Mirrors are ubiquitous now, but were absent during our evolutionary history; hence it is hard to predict, and empirically unknown, whether human kin recognition is family- or self-referential. Here we put this issue to the strongest possible test by comparing nepotistic behaviour towards self- versus co-twin-resemblant individuals. Seventy monozygotic and dizygotic twins were shown same-sex faces, covertly manipulated to resemble either themselves or their co-twin, and indicated which individual they would prefer in two prosocial contexts. Self-resemblant faces were significantly preferred to twin-resemblant faces, showing that visual information about the self supersedes that about close family members in the kin-recognition template. Because, under conditions of paternal uncertainty, a reliable family-referent template could be based only on one''s mother and maternal relatives, a unique advantage of self-referent phenotype matching is the possibility of (consciously or unconsciously) identifying one''s father and paternal relatives as kin.     

Evolutionary personality psychology and victimology: Sex differences in risk attitudes and short-term orientation and their relation to sex differences in victimizations

Men are more often victims of events like car accidents or (violent) crimes than women with the sole exception of sexual assault. Based on the theory of sexual selection, it has been argued that these sex differences in both perpetration and victimization rates can be attributed to sex differences in risk taking and short-term orientation. Men are expected to be more risk prone than women because throughout evolutionary history, men had to engage in a higher level of intrasexual competition. However, despite the theoretical plausibility and empirical evidence at the behavioral level, there is little direct evidence that risk attitudes and short-term orientation as a sexually dimorphic personality trait mediate rates of victimization. Measures of risk attitude and short-term orientation administered to a German student sample (N=275) showed that: (1) the likelihood of being victimized by different kinds of negative events did correlate with both the risk attitudes and short-term orientation of a (potential) victim, (2) men had a more positive attitude towards risks and were more short-term oriented than women, and (3) sex differences in victimization rates were mediated by sex differences in risk attitudes, implying a close link between risk attitude and short-term orientation. We also show that women's risk of being raped is related to their individual risk attitude scores.     

Unexpected changes in urinary catecholamines and vanillylmandelic acid following rape assault

Although psychological changes are recognized to occur in rape assault survivors there is no information on the biochemical changes in these victims. This study compares urinary catecholamines and metabolites in 17 rape victims to two female control groups (one of which engaged in normal sexual intercourse and the other did not). We found, in the rape victims, unexpected changes in the excretion pattern of catecholamines and metabolites as compared to the various control groups. The most significant difference was the dramatic increase in urinary conjugated dopamine (P less than 0.01) in the rape victims which remained elevated for over 24 hr. Urinary vanillylmandelic acid (VMA) rose significantly in rape assault victims when compared to the normal control group. The VMA levels in rape victims were significantly lower, however, than in the women who had undergone (normal) sexual intercourse (P less than 0.01). Urinary free epinephrine showed a marked decline and remained depressed for over 24 hr in the rape assault victims (P less than 0.01) compared to normal controls. Some possible reasons for these patterns in catecholamines and metabolite excretion are suggested. These changes may be of importance in the poststress syndrome that occurs following the rape assault. In summary, a different profile of catecholamine and metabolite excretion patterns was found in rape compared to normal sexual intercourse. The enhanced dopamine excretion is contrary to the expected change of enhanced epinephrine secretion in severe stress.     

Competition as a source of constraint on life history evolution in natural populations

Competition among individuals is central to our understanding of ecology and population dynamics. However, it could also have major implications for the evolution of resource-dependent life history traits (for example, growth, fecundity) that are important determinants of fitness in natural populations. This is because when competition occurs, the phenotype of each individual will be causally influenced by the phenotypes, and so the genotypes, of competitors. Theory tells us that indirect genetic effects arising from competitive interactions will give rise to the phenomenon of ‘evolutionary environmental deterioration'', and act as a source of evolutionary constraint on resource-dependent traits under natural selection. However, just how important this constraint is remains an unanswered question. This article seeks to stimulate empirical research in this area, first highlighting some patterns emerging from life history studies that are consistent with a competition-based model of evolutionary constraint, before describing several quantitative modelling strategies that could be usefully applied. A recurrent theme is that rigorous quantification of a competition''s impact on life history evolution will require an understanding of the causal pathways and behavioural processes by which genetic (co)variance structures arise. Knowledge of the G-matrix among life history traits is not, in and of itself, sufficient to identify the constraints caused by competition.     

Prevalence and predictors of “nesting”: Solutions to adaptive challenges faced during pregnancy

Throughout human evolutionary history, women have faced significant adaptive challenges during pregnancy. Natural selection may therefore have favored psychological mechanisms to help women prepare for birth and motherhood. Previous researchers have conceptualized such mechanisms as comprising a form of “nesting,” consisting of selectivity in one's social relationships and motivations to prepare a safe and clean environment, both of which may have been beneficial in the context of childbirth and childrearing. The current study aimed to replicate and extend previous evidence for nesting (Anderson & Rutherford, 2013). Consistent with prior work, results suggest that pregnant women (n = 91) engaged in more nesting than non-pregnant women (n = 102), and that degree of nesting increased across weeks of gestation. Among pregnant women, high levels of germ aversion and having relatively high socioeconomic status were both associated with heightened nesting. A number of other theoretically relevant variables (e.g., progesterone, oxidative stress, sociosexual orientation) displayed null associations with nesting. Findings strengthen support for the hypothesis that nesting is a pervasive phenomenon among pregnant women and provide new insight into predictors of nesting.     

Taming fitness: Organism‐environment interdependencies preclude long‐term fitness forecasting

Fitness is a central but notoriously vexing concept in evolutionary biology. The propensity interpretation of fitness is often regarded as the least problematic account for fitness. It ties an individual's fitness to a probabilistic capacity to produce offspring. Fitness has a clear causal role in evolutionary dynamics under this account. Nevertheless, the propensity interpretation faces its share of problems. We discuss three of these. We first show that a single scalar value is an incomplete summary of a propensity. Second, we argue that the widespread method of “abstracting away” environmental idiosyncrasies by averaging over reproductive output in different environments is not a valid approach when environmental changes are irreversible. Third, we point out that expanding the range of applicability for fitness measures by averaging over more environments or longer time scales (so as to ensure environmental reversibility) reduces one's ability to distinguish selectively relevant differences among individuals because of mutation and eco‐evolutionary feedbacks. This series of problems leads us to conclude that a general value of fitness that is both explanatory and predictive cannot be attained. We advocate for the use of propensity‐compatible methods, such as adaptive dynamics, which can accommodate these difficulties.     

EVOLUTIONARY GAMES IN WRIGHT'S ISLAND MODEL: KIN SELECTION MEETS EVOLUTIONARY GAME THEORY

This article studies evolutionary game dynamics in Wright's infinite island model. I study a general n×n matrix game and derive a basic equation that describes the change in frequency of strategies. A close observation of this equation reveals that three distinct effects are at work: direct benefit to a focal individual, kin‐selected indirect benefit to the focal individual via its relatives, and the cost caused by increased kin competition in the focal individual's natal deme. Crucial parameters are the coefficient of relatedness between two individuals and its analogue for three individuals. I provide a number of examples and show when the traditional inclusive fitness measure is recovered and when not. Results demonstrate how evolutionary game theory fits into the framework of kin selection.     

An evolutionary approach to grief-related rumination: Construction and validation of the Bereavement Analytical Rumination Questionnaire

There has been little evolutionarily oriented empirical research on the intense, repetitive thoughts—ruminations—that often occur during grief. We used evolutionary theory to develop a new instrument for evaluating grief-related rumination titled the Bereavement Analytical Rumination Questionnaire (BARQ) operationalized by two dimensions: root cause analysis (RCA), the analysis of the cause of the loss; and reinvestment analysis (RIA), the analysis of how to reinvest time and effort in meaningful (presumably fitness enhancing) activities. We administered the BARQ to a sample of people seeking help for grief from non-profit organizations (619 completers) and tested several evolutionary predictions about grief-related rumination. The sample had several signs of severe grief, making it clinically relevant (sleep disturbances, chronicity, psychotropic drug use). Rumination was higher among antidepressant users, suggesting that rumination is related to depression. We also found evidence that grief-related rumination is modulated by circumstances (e.g., type of loss, age and gender of the participant, age of the deceased, traumatic death), which suggests adaptive regulation. Our most important results are consistent with inclusive fitness theory. Specifically, the pattern suggests that as people grow older, they spend less time ruminating about the causes of direct fitness losses (the loss of their own children), and they spend more time ruminating about the causes of indirect fitness losses (e.g., the loss of young non-parental, non-offspring relatives). We also found a sex or gender difference in grief-related rumination that is consistent with other evidence that women have a greater impact on the survival of close relatives (particularly, children and grandchildren), as well as evidence that women have more to lose with the loss of a close social partner. Overall, we found little support for the hypothesis that grief-related rumination is disordered.     

Adaptive attentional attunement: evidence for mating-related perceptual bias

Substantial evidence suggests that physical attractiveness plays an important role in shaping overt mating preferences, judgments, and choices. Relatively few studies, however, have investigated the hypothesis that perceivers are attuned to signs of attractiveness at early, lower-order stages of social perception. In the current research, a visual cueing task was used to assess biases in attentional disengagement—the extent to which people's attention becomes “stuck” on particular social stimuli. Findings indicate that, consistent with some evolutionary theories, perceivers of both sexes exhibited attentional attunement to attractive women, but not attractive men. Additional findings suggest that this bias was pronounced in sexually unrestricted men and in women who felt insecure about a current romantic relationship. This research provides novel evidence for adaptive, lower-order perceptual attunements in the domain of human mating.     

Rape revisited: sexual violence against women in the former Yugoslavia

This article presents information on the rape of women in the former Yugoslavia, focusing more on Muslim women in Bosnia-Herzegovina, and examines the evolutionary, sociological, psychological, and feminist theories of this form of sexual violence. Using a case study approach, through documentation from newspapers and other media accounts, this paper investigated the sexual violence that featured strongly in the campaign of ethnic cleansing or genocide of Muslims in Bosnia-Herzegovina. It was noted that the variables of power, sex, and aggression in the context of war seem to be linked. This is particularly evident when authority legitimates sexual aggression. Without the backing of authority, some rape is expected, but not of such proportion or brutality. In terms of the theories, the evolutionary perspective appears to have limited applicability in explaining rape as an act of war. However, the feminist and macrosociological multivariate theories that focus on heterogeneity of the population, a cultural foundation of very traditional gender roles, and a historical tradition that legitimates sexual violence by armies in war-time, provide more persuasive insights.     

Sex differences in friendship preferences

Friendships can help us solve a number of challenges, increasing our welfare and fitness. Across evolutionary time, some of the many challenges that friendships helped to solve may have differed between men and women. By considering the specific and potentially distinct recurrent problems men's and women's friendships helped them solve, we can derive predictions about the qualities that would have made men's and women's same-sex friends ideal partners. This logic leads to several predictions about the specific friend preferences that may be differentially prized by men and women. Across three studies (N = 745) with U.S. participants—assessing ideal hypothetical friends, actual friends, and using a paradigm adapted from behavioral economics—we find that men, compared to women, more highly value same-sex friends who are physically formidable, possess high status, possess wealth, and afford access to potential mates. In contrast, women, compared to men, more highly value friends who provide emotional support, intimacy, and useful social information. Findings suggest that the specific friendship qualities men and women preferred differed by sex in ways consistent with a functional account of friendship.     

The evolution of chemical defenses along invasion routes: Harmonia axyridis Pallas (Coccinellidae: Coleoptera) as a case study

The evolution of increased competitive ability (EICA) hypothesis (Blossey & Nötzold, 1995 ) postulates that escaping from coevolved enemies increases invaders fitness by energy reallocation from defenses and immunity to growth and reproduction. In this context, we evaluated the evidence of evolutionary change in invasive populations of Harmonia axyridis Pallas (Coccinellidae: Coleoptera). We measured egg defenses—cocktail of hydrocarbons on the egg's surface flagging egg toxicity and the concentration of the main alkaloid harmonine—in individuals from three populations along the invasion route (Japan: native, United States: introduced more than 30 years ago, South Africa: introduced in the early 2000s) in a common garden experiment. Our results support the EICA hypothesis: We found changes along the invasion route in the profiles of the hydrocarbons coating the eggs’ surface and a decrease in the concentration of harmonine in eggs from the most recent invasive South African population compared to the long established in the United States and the native Japanese ones.     

Gendered fitness interests: A method partitioning the effects of family composition on socio-political attitudes and behaviors

Whereas most people are biologically either male or female, their genetic interests are almost never aligned with just their own sex. Drawing on the evolutionary theory of inclusive fitness gained through relatives, we partition the effects of kin on fitness into those that derive from female versus male relatives. We argue that the balance of these female- and male-derived effects, which we call ‘Gendered Fitness Interests’ (GFI), might influence human behavior, especially the adoption of socio-political attitudes that have a gendered dimension. Our proposal builds on observations that an individual's socio-political views covary with the sex of their children or the numbers of relatives of each sex. Further, it is consistent with the relatively small average differences between women's and men's socio-political positions. We outline a method for partitioning GFI, and use simulation models to explore some of its properties. We then show that (1) the GFI component of women's and men's socio-political attitudes will converge, on average, with age. (2) The contributions of both descendent and non-descendent kin lead to considerable variation in GFI. (3) When men have longer average reproductive lifespans than women, GFI can show small male-biases. (4) Paternity uncertainty reduces the variation in GFI between individuals, and (5) Large family sizes are associated with more variation among individuals in GFI. Our proposal provides a framework for the study of the effects of kin on traits and attitudes with a gendered dimension. In this respect, it may prove generally useful in resolving the complex origins of gendered behavior.