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)

Ninety-five freshmen each recruited three peers to play a "group bidding game," an N-person prisoner’s dilemma in which anyone could win movie tickets depending on their scores in the game. Prior to playing, all participants completed a measure of prosocial value orientation. Replicating and extending earlier findings (Sheldon and McGregor 2000), our results show that prosocial participants were at a disadvantage within groups. Despite this vulnerability, prosocial participants did no worse overall than asocial participants because a counteracting group-level advantage arose (...) for prosocials, who tended to be concentrated in groups. Implications of this assortative process for the egoism/altruism debate, and for hierarchical selection theory, are discussed. (shrink)

Spousal correlation in risk attitude is estimated using data from the German Socio-Economic Panel over the period 2004–2009. We apply the bivariate panel ordered probit model to the analysis of the simultaneous determination of the male’s and the female’s risk attitude, using the survey question about general willingness to take risk, provided on a 0–10 Likert-scale. The correlations between both the individual-specific effects of the two partners and the two within-individual errors are separately estimated, and found to be +0.285 and (...) +0.310, respectively. We consider the former to be a key parameter, since its positive sign may be interpreted in terms of positive assortative mating on risk attitude: individuals tend to form partnerships with others having a similar risk attitude. We also find evidence that this correlation increases with years of marriage, suggesting either a form of spousal socialization or a selection process in which marriage breakdown is more likely in poorly matched couples. (shrink)

In one-shot public goods dilemmas, defection is the strictly dominant strategy. However, agents with cooperative strategies can do well if (1) agents are `translucent' (that is, if agents can fallibly recognize the strategy other agents play ex ante ) and (2) an institutional structure allows `assortation' such that cooperative agents can increase the likelihood of playing with their own kind. The model developed in this article shows that even weak levels of translucency suffice if cooperators are able to pool their (...) information to exclude defectors. Computer simulations confirm this claim. The results imply that conditional cooperation can be a successful strategy given translucency and `assortation', even if the game has a one-shot character. The article discusses implications for moral theory against the backdrop of `virtual self-regard' and the concept of moral integrity. Key Words: public good • game theory • prisoner's dilemma • translucency • assortation • group formation • group identity • integrity • altruism. (shrink)

This paper discusses alternative measures of assortative matching and relates them to Sewall Wright’s F-statistic. It also explores applications of measures of assortativity to evolutionary dynamics. We generalize Wright’s statistic to allow the possibility that some types match more assortatively than others, and explore the possibility of identifying parameters of this more general model from the observed distribution of matches by the partners’ types.

Height preferences reflecting positive assortative mating for height—wherein an individual’s own height positively predicts the preferred height of their mate—have been observed in several distinct human populations and are thought to increase reproductive fitness. However, the extent to which assortative preferences for height differ strategically for short-term versus long-term relationship partners, as they do for numerous other indices of mate quality, remains unclear. We explore this possibility in a large representative sample of over 500 men and women aged 15–77 from (...) Canada, Cuba, Norway and the United States. Participants’ own heights were measured, and they indicated their height preferences for a long-term and short-term mate using graphic stimuli containing metric indices. Replicating the “male-taller norm,” participants on average preferred taller-than-average male mates, and shorter-than-average female mates. Positive assortative preferences for height were observed across sexes and samples, however the strength of these height preferences varied with relationship context for men, and not for women. Taller men preferred relatively shorter women for short-term relationships than for long-term relationships, indicating stronger assortative preferences for height in a long-term context. These results provide preliminary evidence that, in addition to mate preferences for other physical traits related to mate quality such as masculinity in the body, face, and voice, assortative preferences for height do vary as a function of expected relationship length, but this was surprisingly only observed in preferences for female height. (shrink)

Decisions concerning price development are best visible in view of their direct impact on the market activities of the company and the general level of profitability. In every activity, the success is measured by an excess of sales revenue over the costs of used resources. In an ideal case, a determined price provides the highest margin resulting from an analysis of the sales volume, takes into consideration the customer's evaluation of the product/service, and allows to react to competitive threats and (...) to fend off the competition's attacks. There is no single universal way to develop prices for various enterprise types, regardless of the conditions of demand, the specific character of the sector they operate in, or the competitive situation, even if we assume that the enterprise has only one goal of activity. That's why, Author recommends three price determination methods. The ways of price determination presented in this article are just the first step on the way to reach the optimal prices. The prices determined in such way, as well as product or service prices already functioning in the market, are subject to modification depending on the assumed goals, taking into consideration the character of demand for a given commodity and the behaviour of the competition. (shrink)

For five individuals, a social network was constructed from a series of his or her dreams. Three important network measures were calculated for each network: transitivity, assortativity, and giant component proportion. These were monotonically related; over the five networks as transitivity increased, assortativity increased and giant component proportion decreased. The relations indicate that characters appear in dreams systematically. Systematicity likely arises from the dreamer's memory of people and their relations, which is from the dreamer's cognitive social network. But (...) the dream social network is not a copy of the cognitive social network. Waking life social networks tend to have positive assortativity; that is, people tend to be connected to others with similar connectivity. Instead, in our sample of dream social networks assortativity is more often negative or near 0, as in online social networks. We show that if characters appear via a random walk, negative assortativity can result, particularly if the random walk is biased as suggested by remote associations. (shrink)

We investigate the long-term evolution of degree-degree correlations (assortativity) in functional brain networks from epilepsy patients. Functional networks are derived from continuous multi-day, multi-channel electroencephalographic data, which capture a wide range of physiological and pathophysiological activities. In contrast to previous studies which all reported functional brain networks to be assortative on average, even in case of various neurological and neurodegenerative disorders, we observe large fluctuations in time-resolved degree-degree correlations ranging from assortative to dissortative mixing. Moreover, in some patients these (...) fluctuations exhibit some periodic temporal structure which can be attributed, to a large extent, to daily rhythms. Relevant aspects of the epileptic process, particularly possible pre-seizure alterations, contribute marginally to the observed long-term fluctuations. Nevertheless, our findings suggest that physiological and pathophysiological activity may modify functional brain networks in a different and process-specific way. We evaluate factors that possibly influence the long-term evolution of degree-degree correlations. (shrink)

Fincher & Thornhill's (F&T's) model is not entirely supported by common patterns of affect behaviors among people who live under varying climatic conditions and among people who endorse varying levels of (Western) religiosity and conservative political ideals. The authors' model is also unable to account for intra-regional heterogeneity in assortative sociality, which, we argue, can be better explained by a framework that emphasizes the differential expression of fundamental social cues for maintaining distinct social network structures.

The preferential attachment mechanism that forms scale-free network cannot display assortativity, i.e., the degree of one node is positively correlated with that of their neighbors in the network. Given the attributes of network nodes, a cultural trait-matching mechanism is further introduced in this paper. Both theoretical analysis and simulation results indicate that the higher selection probability of such mechanism, the more obvious the assortativity is shown in networks. Further, the degree of nodes presents a positive logarithm correlation with (...) that of adjacent ones. Finally, this study discusses the theoretical and practical significances of the introduction of such a cultural trait-matching mechanism. (shrink)

A computer-based language system exploring hybrid invention generation has been developed by Bill Seaman working in conjunction with the programmer Gideon May.1 The project was primarily funded by Intel. This work explores 3D visualization with related generative texts and recombinant audio/music, as well as a series of textual descriptions. Computer-based environmental meaning is explored through the inter-authorship and operative experiential examination of a diverse set of media-elements and media-processes, in this case focusing on the virtual construction of hybrid inventions. Differing (...) sets of media elements in the Hybrid Invention Generator convey their own fields of meaning through the juxtaposition of 3D models, texts and digital audio. Varying combinations of these fields of meaning are experienced through direct interaction with the system. The work explores notions surrounding machinic genetics. Nonsense relations can present seemingly off-kilter juxtapositions, providing the participant with an experience akin to surrealism. Lautréamont’s definition of surrealist beauty - ‘beautiful as the unexpected meeting, on a dissection table, of a sewing machine and an umbrella’ (Waldberg 1965) - describes an experience engendered through a unique juxtaposition of elements not unlike relations encountered within this particular techno-poetic environment. Yet the system can also be used to brainstorm actual devices, as well as their potential conceptual/functional construction. (shrink)

Uchiyama et al. productively discuss how culture can influence genetic heritability and, by modifying environmental conditions, limit the generalizability of genome-wide association studies (GWASs). Here, we supplement their account by highlighting how recent changes in culture and institutions in industrialized, westernized societies – such as increased female workforce participation – may have increased assortative mating. This alters the distribution of genotypes themselves, increasing heritability and phenotypic variance, and may be detectable using the latest methods.

Using computer simulations I studied the simultaneous effect of variable environments, mutation rates, ploidy, number of loci subject to evolution and random and assortative mating on various reproductive systems. The simulations showed that mutants for sex and recombination are evolutionarily stable, displacing alleles for monosexuality in diploid populations mating assortatively under variable selection pressure. Assortative mating reduced excessive allelic variance induced by recombination and sex, especially among diploids. Results suggest a novel adaptive value for sex and recombination. They show that (...) the adaptive value of diploidy and that of the segregation of sexes is different to that of sex and recombination. The results suggest that the emergence of sex had to be preceded by the emergence of diploid monosexual organisms and provide an explanation for the emergence and maintenance of sex among diploids and for the scarcity of sex among haploid organisms. (shrink)

Advances in multiagent simulation techniques make it possible to study more realistic dynamics of complex systems and allow evolutionary theories to be tested. Here I use simulations to assess the relative importance of reproductive systems (haplodiploidy vs. diploidy), mate selection (assortative mating vs. random mating) and social economics (pay-off matrices of evolutionary games) in the evolutionary dynamics leading to the emergence of social cooperation in the provision of parental care. The simulations confirm that haplo-diploid organisms and organisms mating assortatively have (...) a higher probability for fixing alleles and require less favorable conditions for their fixation, than diploids or organisms mating randomly. The simulations showed that social behavior was most likely to emerge a) when the cost for parental investment was much lower than the benefits to the offspring, b) when cooperation improved synergistically the fitness of offspring compared to the corresponding egoistic behavior and c) when alleles coding for altruistic or social behavior could be rapidly fixed in the population, thanks to mechanisms such as haplo-diploidy and/or assortative mating. Cooperative social behavior always appeared if sociality conferred much higher fitness gains compared to non cooperative alternatives suggesting that the most important factors for the emergence and maintenance of social behavior are those based on energetic or efficiency considerations. The simulations, in congruence with the scant experimental evidence available, suggest that economic considerations rather than genetic ones are critical in explaining the emergence and maintenance of sociality. (shrink)

The target article gives two explanations for the correlation between pathogens, family ties, and religiosity: one highlights the benefits of xenophobic attitudes for reducing pathogen exposure, the other highlights the benefits of ethnic loyalty for mitigating the costs when a person falls ill. Preliminary data from traditional societies provide some support for the former explanation but not the latter.

Any biological species of biparental organisms necessarily includes, and is fundamentally dependent on, sign processes between individuals. In this case, the natural category of the species is based on family resemblances, which is why a species is not a natural kind. We describe the mechanism that generates the family resemblance. An individual recognition window and biparental reproduction almost suffice as conditions to produce species naturally. This is due to assortativity of mating which is not based on certain individual traits, (...) but on the difference between individuals. The biosemiotic model described here explains what holds a species together. It also implies that boundaries of a species are fundamentally fuzzy, and that character displacement occurs in case of sympatry. Speciation is a special case of discretisation that is an inevitable result of any communication system in work. The biosemiotic mechanism provides the conditions and communicative restrictions for the origin and persistence of diversity in the realm of living systems. (shrink)

No single theory so far proposed gives a wholly satisfactory account of the origin and maintenance of bird-song dialects. This failure is the consequence of a weak comparative literature that precludes careful comparisons among species or studies, and of the complexity of the issues involved. Complexity arises because dialects seem to bear upon a wide range of features in the life history of bird species. We give an account of the principal issues in bird-song dialects: evolution of vocal learning, experimental (...) findings on song ontogeny, dialect descriptions, female and male reactions to differences in dialect, and population genetics and dispersal.We present a synthetic theory of the origin and maintenance of song dialects, one that accommodates most of the different systems reported in the literature. The few data available suggest that large, regional dialect populations are genetically differentiated; this pattern is correlated with reduced dispersal between dialects, assortative mating by females, and male-male exclusion. At the same time, “subdialects” may be formed within regional dialects. Subdialect clusters are usually small and may represent vocal mimicry among a few adjacent territorial males. The relative importance of genetic and social adaptation may contribute to the emergence of subdialects; their distinctiveness may be correlated with the degree of polygyny, for example. Thus, subdialect formation is linked to one theory of the evolution of repertoire size, but data are too fragmentary to examine this idea critically. (shrink)

In the target article, we presented the hypothesis that parasite-stress variation was a causal factor in the variation of in-group assortative sociality, cross-nationally and across the United States, which we indexed with variables that measured different aspects of the strength of family ties and religiosity. We presented evidence supportive of our hypothesis in the form of analyses that controlled for variation in freedom, wealth resources, and wealth inequality across nations and the states of the USA. Here, we respond to criticisms (...) from commentators and attempt to clarify and expand the parasite-stress theory of sociality used to fuel our research presented in the target article. (shrink)

In the target article, we presented the hypothesis that parasite-stress variation was a causal factor in the variation of in-group assortative sociality, cross-nationally and across the United States, which we indexed with variables that measured different aspects of the strength of family ties and religiosity. We presented evidence supportive of our hypothesis in the form of analyses that controlled for variation in freedom, wealth resources, and wealth inequality across nations and the states of the USA. Here, we respond to criticisms (...) from commentators and attempt to clarify and expand the parasite-stress theory of sociality used to fuel our research presented in the target article. (shrink)

In the target article, we presented the hypothesis that parasite-stress variation was a causal factor in the variation of in-group assortative sociality, cross-nationally and across the United States, which we indexed with variables that measured different aspects of the strength of family ties and religiosity. We presented evidence supportive of our hypothesis in the form of analyses that controlled for variation in freedom, wealth resources, and wealth inequality across nations and the states of the USA. Here, we respond to criticisms (...) from commentators and attempt to clarify and expand the parasite-stress theory of sociality used to fuel our research presented in the target article. (shrink)

An assortment of different points of view on conspiracy thinking and conspiracy theories, pro and con.

Group assortative biases are stronger in regions where pathogen stress has been historically prevalent. Pushing the logic of this approach, extensions should include investigations of how cultural norms related to prosociality and relational striving may also covary with regional pathogen stress. Likewise, the pan-specific observation that diseased animals show decreased motor activity to facilitate recovery suggests that norms relevant to sickness behaviors may also vary as a function of regional parasite stress.

Assorted fruit from forty years' writing, these essays by David Braybrooke discuss (in Part One of the book) a variety of concrete, practical topics that ethical concerns bring into politics: people's interests; their needs as well as their preferences; their work and their commitment to work; their participation in politics and in other group activities. Essays follow on the justice with which theme matters are arranged for and on the common good in which they are consolidated. Justice here inspires a (...) 'departures' approach, which moves from agreement on departures from commutative justice to agreement on measures of distributive justice needed to forestall such departures. Another essay (first published here) radically undermines the odd but entrenched belief that utilitarianism classically licenced, even prescribed, systematically sacrificing the happiness of some people to give others greater pleasure. Part II and Part III of the book concentrate upon the subject of settled social rules, which are devices for securing the objectives treated in Part I. Part II shows that rules are ubiquitous in ethics, since there are no virtues without rules, just as there are no (justified) rules; without virtues. Part Two also shows that rules are as ubiquitous in social phenomena as the causal regularities sought by one school of social science. Part III captures the dialectic of history at least in part by a logical analysis of changes in rules following the onset of quandaries. It then considers how political choices can be both prudent, by keeping within duly considered incremental limits, and yet imaginative enough to escape the recent embarrassments generated by social choice theory. Characteristically versatile in topic and style, Braybrooke offers original light on all theme subjects. One reader has commented, ' His] prose is elegant and always a pleasure to read. Some of the pieces are nothing short of brilliant.' Which did the reader have in mind? Readers may differ (they already have) on just which pieces they would rank highest. (shrink)