The finding that women are attracted to men older than themselves whereas men are attracted to relatively younger women has been explained by social psychologists in terms of economic exchange rooted in traditional sex-role norms. An alternative evolutionary model suggests that males and females follow different reproductive strategies, and predicts a more complex relationship between gender and age preferences. In particular, males' preferences for relatively younger females should be minimal during early mating years, but should become more pronounced as the (...) male gets older. Young females are expected to prefer somewhat older males during their early years and to change less as they age. We briefly review relevant theory and present results of six studies testing this prediction. Study 1 finds support for this gender-differentiated prediction in age preferences expressed in personal advertisements. Study 2 supports the prediction with marriage statistics from two U.S. cities. Study 3 examines the cross-generational robustness of the phenomenon, and finds the same pattern in marriage statistics from 1923. Study 4 replicates Study 1 using matrimonial advertisements from two European countries, and from India. Study 5 finds a consistent pattern in marriages recorded from 1913 through 1939 on a small island in the Philippines. Study 6 reveals the same pattern in singles advertisements placed by financially successful American women and men. We consider the limitations of previous normative and evolutionary explanations of age preferences and discuss the advantages of expanding previous models to include the life history perspective. (shrink)

In both biology and the human sciences, social groups are sometimes treated as adaptive units whose organization cannot be reduced to individual interactions. This group-level view is opposed by a more individualistic one that treats social organization as a byproduct of self-interest. According to biologists, group-level adaptations can evolve only by a process of natural selection at the group level. Most biologists rejected group selection as an important evolutionary force during the 1960s and 1970s but a positive literature began to (...) grow during the 1970s and is rapidly expanding today. We review this recent literature and its implications for human evolutionary biology. We show that the rejection of group selection was based on a misplaced emphasis on genes as “replicators” which is in fact irrelevant to the question of whether groups can be like individuals in their functional organization. The fundamental question is whether social groups and other higher-level entities can be “vehicles” of selection. When this elementary fact is recognized, group selection emerges as an important force in nature and what seem to be competing theories, such as kin selection and reciprocity, reappear as special cases of group selection. The result is a unified theory of natural selection that operates on a nested hierarchy of units.The vehicle-based theory makes it clear that group selection is an important force to consider in human evolution. Humans can facultatively span the full range from self-interested individuals to “organs” of group-level “organisms.” Human behavior not only reflects the balance between levels of selection but it can also alter the balance through the construction of social structures that have the effect of reducing fitness differences within groups, concentrating natural selection (and functional organization) at the group level. These social structures and the cognitive abilities that produce them allow group selection to be important even among large groups of unrelated individuals. (shrink)

Mealey proposes two categorical classes of sociopath, primary and secondary. I criticize this distinction on the basis that constructs of this kind have proved unrealistic in personality taxonomy and that dimensional systems capture reality much more successfully. I suggest how such a system could work in this particular context.

This commentary extends arousal theory to suggest an explanation for the well-established inverse correlation between church attendance and involvement in crime. In addition, the results of two surveys of social scientists are reviewed to reveal just how little impact the biosocial/sociobiological perspective has had thus far on social science.

Recent studies lend support to the two-pathway model of the evolution of sociopathy with evidence that: 1) psychopathy (primary sociopathy) is a discrete type and 2) in general, sociopaths have relatively high levels of reproductive success. Hare's Psychopathy Checklist may provide a start for the revision of terminology that will be necessary to distinguish between primary and secondary trajectories.

Emotion is critical in Mealey's conceptual arguments. However, several of her assertions about the role of emotion in sociopathy are problematic. Questions are raised regarding the link between lack of anxiety and low levels of secondary emotions such as love and sympathy, the argument that sociopaths are low in anxiety but high in neuroticism, and the designation of anxiety as a secondary emotion.

A consideration of the genetics of sociopathy suggests the following. The author's Evolutionary Stable Strategy (ESS) types 2 to 4 are more likely than types 1 and 5 in crimes of violence, and there may not be an ESS for crimes of property or for sociopathy. Correlations between sociopathy and crimes of property are also more likely due to environmental than to genetic variants, and correlations between sociopathy and crimes of property are due more to environmental than genetic variants.

Sociopaths are “outstanding” members of society in two senses: politically, they draw our attention because of the inordinate amount of crime they commit, and psychologically, they hold our fascination because most ofus cannot fathom the cold, detached way they repeatedly harm and manipulate others. Proximate explanations from behavior genetics, child development, personality theory, learning theory, and social psychology describe a complex interaction of genetic and physiological risk factors with demographic and micro environmental variables that predispose a portion of the population (...) to chronic antisocial behavior. More recent, evolutionary and game theoretic models have tried to present an ultimate explanation of sociopathy as the expression of a frequency-dependent life strategy which is selected, in dynamic equilibrium, in response to certain varying environmental circumstances. This paper tries to integrate the proximate, developmental models with the ultimate, evolutionary ones, suggesting that two developmentally different etiologies of sociopathy emerge from two different evolutionary mechanisms. Social strategies for minimizing the incidence of sociopathic behavior in modern society should consider the two different etiologies and the factors that contribute to them. (shrink)

An evolutionary approach to ethics supports, to some extent, the sceptical meta-ethics found by some of the Greek sophists and Nietzsche. On the other hand, a modern naturalistic account on the origin and nature of morality, leads to somewhat different conclusions. This is demonstrated with an answer to three philosophical questions: does real freedom exist?, does the good, or real virtue, exist?, does life have a meaning?

The present discussion of sociobiological approaches to ethnic nepotism takes Pierre van den Berghe ʼs theory as a starting point. Two points, which have not been addressed in former analyses, are considered to be of particular importance. It is argued that the behavioral mechanism of ethnic nepotism—as understood by van den Berghe—cannot explain ethnic boundaries and attitudes. In addition, I show that van den Bergheʼs central premise concerning ethnic nepotism is in contradiction to Hamiltonʼs formula, the essential principle of kin (...) selection theory. It is further discussed how other approaches that make reference to ethnic nepotism are related to van den Bergheʼs account and its problems. I conclude with remarks on the evolutionary explanation of ethnic phenomena. (shrink)

Social scientists have not integrated relevant knowledge from the biological sciences into their explanations of human behavior. This failure is due to a longstanding antireductionistic bias against the natural sciences, which follows on a commitment to the view that social facts must be explained by social laws. This belief has led many social scientists into the error of reifying abstract analytical constructs into entities that possess powers of agency. It has also led to a false nature-culture dichotomy that effectively undermines (...) the place of biology in social scientific explanation. Following the principles of methodological individualism, we show how behavioral explanations supported by data and theory from the neurosciences can be used to correct the errors of reificationist thinking in the social sciences. We outline a mechanistic approach to the explanation of human behavior with the hope that the biological sciences will begin to find greater acceptance among social scientists. (shrink)

We doubt that primary sociopathy is adaptive, for three reasons: First, its prevalence is too low to require an adaptive explanation. Second, a common sequela of damage to the orbito-frontal lobes is Any pattern of behavior that can be produced by brain damage is unlikely to be adaptive. Third, we argue that most human social behavior is not under tight genetic control, but is produced by open-ended calculation of fitness-contingencies.

Sociobiological explanation requires both a reliable and a valid definition of the sociopathy phenotype. Mealey assumes that such reliable and valid definition of sociopathy exists in her A review of psychiatric literature on the diagnosis of antisocial personality disorder clearly demonstrates that this assumption is faulty. There is substantial disagreement among diagnostic systems (e.g., RDC, DSM-III) over what constitutes the antisocial phenotype, different systems identify different individuals as sociopathic. Without a valid definition of sociopathy, sociobiological theories like Mealey's should be (...) viewed as entirely speculative. (shrink)

Evolutionary analysis suggests that policies based on deterrence may cope effectively with primary sociopathy if the threat of punishment fits the crime in the cost/benefit calculus of the sociopath, not that of the public. On the other hand, policies designed to offset serious disadvantage in social competition may help inhibit the development of secondary sociopathy, rather than deter its expression.

Unlike some psychiatric illnesses, criminal lifestyles are not reproductive dead ends and may represent frequency-dependent adaptations. Sociopaths may gain reproductively from their greater relative to nonsociopaths. This mating-effort construct should be assessed directly in future studies of sociopathy. Collaboration between biologically oriented and environmentally oriented researchers is needed to investigate the biosocial basis of sociopathy.

Much theorizing about altruism has been undertaken within a naturalistic and deterministic sociobiological framework that has sought to explain altruistic action in terms of underlying genetic selfishness. Recently, however, social constructionist thinkers have developed an alternative to such theorizing which suggests that human action arises out of fundamentally open-ended and malleable social relationships. This paper intends to show, however, that a reductive egoism is nonetheless still at work in such accounts, typically taking the form of an underlying concern for matters (...) of personal status and social recognition. As a response, this paper will briefly outline the work of the French phenomenologists Maurice Merleau-Ponty and Emmanuel Levinas as an example of non-reductive and fundamentally Other-oriented alternatives to both sociobiological and social constructionist accounts of altruistic action. (shrink)

Human cooperation is highly unusual. We live in large groups composed mostly of non-relatives. Evolutionists have proposed a number of explanations for this pattern, including cultural group selection and extensions of more general processes such as reciprocity, kin selection, and multi-level selection acting on genes. Evolutionary processes are consilient; they affect several different empirical domains, such as patterns of behavior and the proximal drivers of that behavior. In this target article, we sketch the evidence from five domains that bear on (...) the explanatory adequacy of cultural group selection and competing hypotheses to explain human cooperation. Does cultural transmission constitute an inheritance system that can evolve in a Darwinian fashion? Are the norms that underpin institutions among the cultural traits so transmitted? Do we observe sufficient variation at the level of groups of considerable size for group selection to be a plausible process? Do human groups compete, and do success and failure in competition depend upon cultural variation? Do we observe adaptations for cooperation in humans that most plausibly arose by cultural group selection? If the answer to one of these questions is “no,” then we must look to other hypotheses. We present evidence, including quantitative evidence, that the answer to all of the questions is “yes” and argue that we must take the cultural group selection hypothesis seriously. If culturally transmitted systems of rules (institutions) that limit individual deviance organize cooperation in human societies, then it is not clear that any extant alternative to cultural group selection can be a complete explanation. (shrink)

Mealey's data do not support her dichotomous model of primary and secondary sociopathy; this data supports the view that there is a continuum of degrees of sociopathy, from zero to the maximal manifestation. There are multitudes of factors that can contribute to sociopathy and the countless different mixes of them can produce multiple degrees and variations of sociopathic behavior.

Although serotonin, testosterone, and genes contribute to sociopathy, the relationships are probably indirect and subject to modifiers (e.g., present only under certain conditions of rearing and temperament). Age at menarche may be a marker variable as well as a causal factor. Since the genders differ in all four areas, sex differences in sociopathy represent a very complex interaction of these factors.

Mealey's sociobiological model of sociopathy could profit from attachment theory, in particular, the theory and research on the basis of the Adult Attachment Interview (Main & Goldwyn 1985–1993). Findings of an adult attachment study in a forensic psychiatric setting are summarized. Three attachment-oriented strategies for families, schools, and forensic settings are proposed to help reduce or prevent secondary sociopathy and criminal recidivism.

Human homogamy may be caused in part by individuals’ preference for phenotypic similarities. Two types of preference can result in homogamy: individuals may prefer someone who is similar to themselves (self-referent phenotype matching) or to their parents (a sexual-imprinting-like mechanism). In order to examine these possibilities, we compare faces of couples and their family members in two ways. First, “perceived” similarity between a pair of faces is quantified as similarity ratings given to the pair. Second, “physical” similarity between two groups (...) of faces is evaluated on the basis of correlations in principal component scores generated from facial measurements. Our results demonstrate a tendency to homogamy in facial characteristics and suggest that the tendency is due primarily to self-referent phenotype matching. Nevertheless, the presence of a sexual-imprinting-like effect is also partially indicated: whether individuals are involved in facial homogamy may be affected by their relationship with their parents during childhood. (shrink)

The validity of the classification of “primary sociopaths” as a qualitatively distinct group in the general population is questioned. Cenetic variation in the experience and expression of emotions may play a role in the development of antisocial behavior. However, research clearly documents that socialization environments powerfully modify the expression of genetic biases in a manner that increases or decreases the risk for “sociopathy.”.

A secondary analysis was performed on preliminary data from an ongoing cross-cultural study on assortative pairing. Independently sampled pairs of opposite-sex romantic partners and of same-sex friends rated themselves and each other on Life History (LH) strategy and mate value. Data were collected in local bars, clubs, coffeehouses, and other public places from three different cultures: Tucson, Arizona; Hermosillo, Sonora; and San José, Costa Rica. The present analysis found that slow LH individuals assortatively pair with both sexual and social partners (...) more strongly than fast LH individuals. We interpret this phenomenon as representing (1) an adaptation for preserving coadapted genomes in slow LH strategists to maintain high copying fidelity genetic replication while producing a lower number of offspring in stable, predictable, and controllable environments and (2) a bet-hedging adaptation in fast LH strategists, favoring the genetic diversification of a higher number of offspring in unstable, unpredictable, and uncontrollable environments. (shrink)

Behavioral biologists have long sought to link behavioral units (e.g., aggression, depression, sociopathy) with biological units (e.g., genes, neurotransmitters, hormones, neuroanatomical loci). These units, originally contrived for descriptive purposes, often lead to misunderstandings when they are reified for purposes of causal analysis. This genetic and biochemical explanation for sociopathy reflects such problems.

The key questions arising from Mealey's analysis are: Do environmental factors such as early maternal rejection also contribute to the emotional deficits observed in psychopaths? Are there psychophysiological protective factors for antisocial behavior that have clinical implications? Does a disinhibited temperament and low arousal predispose to primary psychopathy? Would primary or secondary psychopaths be most characterized by prefrontal dysfunction?

Mealey's excellent target article rests on several assumptions that may be questioned, including the overarching assumption that sociopathy reflects the failure of a small minority of males to cooperate with the larger group. I suggest that violent competition in ancestral bands cheatinggame was the primary evolutionary precursor of sociopathy. Today's violent sociopath is far more a than a failed cooperator.

Results of an agent-based computer simulation of the evolution of diploid sexual organisms showed that several mate selection strategies confer much higher average fitness to the simulated populations, and higher evolutionary stability to the alleles coding for these strategies, than random mating. Strategies which select for ''good genes'' were very successful, and so were strategies based on assortative mating. The results support the hypothesis that mating is not likely to be random in nature and that the most successful mate selection (...) strategies are those based on assortative mating or on advantageous genes. (shrink)

In both biology and the human sciences, social groups are sometimes treated as adaptive units whose organization cannot be reduced to individual interactions. This group-level view is opposed by a more individualistic one that treats social organization as a byproduct of self-interest. According to biologists, group-level adaptations can evolve only by a process of natural selection at the group level. Most biologists rejected group selection as an important evolutionary force during the 1960s and 1970s but a positive literature began to (...) grow during the 1970s and is rapidly expanding today. We review this recent literature and its implications for human evolutionary biology. We show that the rejection of group selection was based on a misplaced emphasis on genes as "replicators" which is in fact irrelevant to the question of whether groups can be like individuals in their functional organization. The fundamental question is whether social groups and other higher-level entities can be "vehicles" of selection. When this elementary fact is recognized, group selection emerges as an important force in nature and what seem to be competing theories, such as kin selection and reciprocity, reappear as special cases of group selection. The result is a unified theory of natural selection that operates on a nested hierarchy of units. The vehicle-based theory makes it clear that group selection is an important force to consider in human evolution. Humans can facultatively span the full range from self-interested individuals to "organs" of group-level "organisms." Human behavior not only reflects the balance between levels of selection but it can also alter the balance through the construction of social structures that have the effect of reducing fitness differences within groups, concentrating natural selection (and functional organization) at the group level. These social structures and the cognitive abilities that produce them allow group selection to be important even among large groups of unrelated individuals. (shrink)