We propose a conceptual model that maps the causal pathways relating biological evolution to cultural change. It builds on conventional evolutionary theory by placing emphasis on the capacity of organisms to modify sources of natural selection in their environment (niche construction) and by broadening the evolutionary dynamic to incorporate ontogenetic and cultural processes. In this model, phenotypes have a much more active role in evolution than generally conceived. This sheds light on hominid evolution, on the evolution of culture, and on (...) altruism and cooperation. Culture amplifies the capacity of human beings to modify sources of natural selection in their environments to the point where that capacity raises some new questions about the processes of human adaptation. Key Words: adaptation; altruism; cooperation; evolutionary psychology; gene-culture coevolution; human evolution; human genetics; niche construction; sociobiology. (shrink)

Altruism is generally understood to be behavior that benefits others at a personal cost to the behaving individual. However, within evolutionary biology, different authors have interpreted the concept of altruism differently, leading to dissimilar predictions about the evolution of altruistic behavior. Generally, different interpretations diverge on which party receives the benefit from altruism and on how the cost of altruism is assessed. Using a simple trait-group framework, we delineate the assumptions underlying different interpretations and show how they relate to one (...) another. We feel that a thorough examination of the connections between interpretations not only reveals why different authors have arrived at disparate conclusions about altruism, but also illuminates the conditions that are likely to favor the evolution of altruism. (shrink)

Most models of generational succession in sexually reproducing populations necessarily move back and forth between genic and genotypic spaces. We show that transitions between and within these spaces are usually hidden by unstated assumptions about processes in these spaces. We also examine a widely endorsed claim regarding the mathematical equivalence of kin-, group-, individual-, and allelic-selection models made by Lee Dugatkin and Kern Reeve. We show that the claimed mathematical equivalence of the models does not hold.

In the traditional system of Chinese families, individuals are embedded in the institution of the family with defined obligations to enhance family development. As a consequence of the male-biased sex ratio at birth in China since the 1980s, an increasing number of surplus rural males have been affected by a marriage squeeze becoming involuntary bachelors. Under China’s universal heterosexual marriage tradition, family development of rural involuntary bachelors has largely been ignored, but in China’s gender-imbalanced society, it is necessary to adopt (...) a family-based approach to identify and study the plight of rural involuntary bachelors. Studies on gender imbalance indicate that these men face multiple risks from the perspectives of their life course, the family life cycle, and the family ethic. To a certain extent, these risks are caused by a conflict between the individual’s family life and family ethics and are mainly reflected in problems concerning marriage, health, and old-age support. Not only do these vulnerabilities affect the individual and family development across the whole life cycle but also pose major risks to social development in the face of strong gender imbalance. In order to deal with risks faced by rural involuntary bachelors, core ethical principles, including autonomy, beneficence, and justice, need to be adopted. Through adjustments to informal support provided by the family and formal support provided by policy-makers, risk of uncertainty in family development faced by rural involuntary bachelors could be reduced. (shrink)

A skew in sex ratio at birth occurs across much of Asia and North Africa. The resulting gender imbalance in favor of men in the adult population causes a number of serious social problems, including increased violence against women and an increasing number of “forced bachelors” in many areas. Here we concentrate on the sex ratio at birth in China and model two causal factors specific to Chinese culture: a traditional preference for sons over daughters and a preference for brides (...) to move to their husband’s natal home. We use cultural niche construction models to explore the interacting effect of both son preference and marriage-type preference on the demography of the region. Finally, we discuss the implications of this model for policy interventions in the future. (shrink)

Group selection, as advocated by Sober and Wilson, is theoretically plausible, although it remains an open question as to what extent it occurs in nature. If group selection has operated in hominids, it is likely to have selected cultural not genetic variation. A focus on niche construction helps delineate the conditions under which cooperation is favoured. Group selection may favour between-group conflict as well as within-group cooperation.

Many factors have contributed to the decline in China’s fertility level. Using China’s population census data from 1990, 2000 and 2010, the present study investigates the factors causing the decline in China’s fertility rate by decomposing changes in two fertility indices: the total fertility rate and the net reproduction rate. The change in the TFR is decomposed into the change in the marital fertility rate and the change in the proportion of married women. Four factors contribute to the change in (...) the NRR. The following are the main findings. A drop in the MFR caused a decrease in the TFR and the NRR between 1989 and 2000. However, the change in MFR increased TFR and NRR between 2000 and 2010. Marriage postponement caused a decline in the fertility level between 1989 and 2000 as well as between 2000 and 2010. The effect of the MFR and marriage postponement varied with age and region and also between urban and rural areas. (shrink)

We propose that food-related uncertainty is but one of multiple cues that predicts harsh conditions and may activate “incentive hope.” An evolutionarily adaptive response to these would have been to shift to a behavioral-metabolic phenotype geared toward facing hardship. In modernity, this phenotype may lead to pathologies such as obesity and hoarding. Our perspective suggests a novel therapeutic approach.

Our response contains a definition of niche construction, illustrations of how it changes the evolutionary process, and clarifications of our conceptual model. We argue that the introduction of niche construction into evolutionary thinking earns its keep; we illustrate this argument in our discussion of rates of genetic and cultural evolution, memes and phenogenotypes, creativity, the EEA (environment of evolutionary adaptedness), and group selection.

Optimizing average path length by adding shortcut edges has been widely discussed in connection with social networks, but the relationship between network diameter and APL is generally ignored in the dynamic optimization of APL. In this paper, we analyze this relationship and transform the problem of optimizing APL into the problem of decreasing diameter to 2. We propose a mathematic model based on a memetic algorithm. Experimental results show that our algorithm can efficiently solve this problem as well as optimize (...) APL. (shrink)