Menstrual cycle variation in women’s preference for the scent of symmetrical men.

Evidence suggests that female sexual preferences change across the menstrual cycle. Women's extra-pair copulations tend to occur in their most fertile period, whereas their intra-pair copulations tend to be more evenly spread out across the cycle. This pattern is consistent with women preferentially seeking men who evidence phenotypic markers of genetic bene¢ts just before and during ovulation. This study examined whether women's olfactory preferences for men's scent would tend to favour the scent of more symmetrical men, most notably during the women's fertile period. College women sni¡ed and rated the attractiveness of the scent of 41 T-shirts worn over a period of two nights by di¡erent men. Results indicated that normally cycling (non-pill using) women near the peak fertility of their cycle tended to prefer the scent of shirts worn by symmetrical men. Normally ovulating women at low fertility within their cycle, and women using a contraceptive pill, showed no signi¢cant preference for either symmetrical or asymmetrical men's scent. A separate analysis revealed that, within the set of normally cycling women, individual women's preference for symmetry correlated with their probability of conception, given the actuarial value associated with the day of the cycle they reported at the time they smelled the shirts. Potential sexual selection processes and proximate mechanisms accounting for these ¢ndings are discussed

Parasite-stress promotes in-group assortative sociality: the cases of strong family ties and heightened religiosity

Throughout the world people differ in the magnitude with which they value strong family ties or heightened religiosity. We propose that this cross-cultural variation is a result of a contingent psychological adaptation that facilitates in-group assortative sociality in the face of high levels of parasite-stress while devaluing in-group assortative sociality in areas with low levels of parasite-stress. This is because in-group assortative sociality is more important for the avoidance of infection from novel parasites and for the management of infection in regions with high levels of parasite-stress compared with regions of low infectious disease stress. We examined this hypothesis by testing the predictions that there would be a positive association between parasite-stress and strength of family ties or religiosity. We conducted this study by comparing among nations and among states in the United States of America. We found for both the international and the interstate analyses that in-group assortative sociality was positively associated with parasite-stress. This was true when controlling for potentially confounding factors such as human freedom and economic development. The findings support the parasite-stress theory of sociality, that is, the proposal that parasite-stress is central to the evolution of social life in humans and other animals

Radiochemical Processing Laboratory High-Level Vault Characterization Report

In July and August 2007, RPL Transition Project staff safely performed field work to remotely characterize the A, B, and C HLVs in the RPL. This report documents the methods and equipment used to collect radiological and chemical characterization samples and summarizes the analytical results

The comparative method in cross-cultural and cross-species research

Comparative methodology is controversial in biology and the related field of research on behavioral and psychological traits across human cultures. We critically examine this controversy. We argue that the widely held opinion of non-independence among historically-related cultures and species errs by not recognizing and incorporating into research the two distinct and complementary categories of causation that account for an extant trait—the phylogenetic origin of the trait (cultural or otherwise) and the maintenance of the trait after its phylogenetic origin. Phylogenetic correction for non-independence is required in the comparative study of a trait’s phylogenetic origin, but is irrelevant for the comparative study of the causation of a trait’s maintenance after its phylogenetic origin. Across cultures, even closely related cultures, causes that are specific to each culture act to maintain cultural similarities, which makes such similarities independent. Among species, even closely related species, similarities are maintained by lineage-specific, and hence independent, evolutionary causal processes. Comparative methodology has been criticized as being inferior to other types of scientific methodology (e.g., experimentation), because it is based on correlational data. This criticism is erroneous because, all scientific findings are correlational, and in hypothesis testing, the ability of an empirical finding to address causation depends solely upon the control of confounding variables, not the type of scientific method itself

The parasite-stress theory of sociality, the behavioral immune system, and human social and cognitive uniqueness.

Parasite adversity was an important source of Darwinian selection in human evolutionary history because parasites selected for a diversity of human behavioral parasite-defenses in addition to the numerous defenses provided by the classical human immune system. We argue for a broader view of behavioral immunity than has been emphasized recently. We propose a new hypothesis for the evolution of the unique cognitive and social adaptations of humans. We argue that, in human evolutionary history, as weaponry and other technologies reduced the importance of the physical environment, typical ecological challenges, and predators as agents of selection shaping mental and social traits, parasites became more important selection agents on these traits. Also, we suggest that the reduction of natural selection in the context of predation in human evolutionary history resulted in selection favoring high pathogenicity in human parasites because predation is focused on debilitated prey and hence selects against pathogenicity in the parasites involved. The new hypothesis argues that, in human evolutionary history, temporal variation in local parasite adversity gave rise to frequent change and complexity in the values that are adaptive for individuals to use in their social navigation in relation to the degree of local disease stress, and that selection in this context accounts for the evolution of aspects of human uniqueness in cognitive ability and sociality. The new hypothesis is akin to the social brain hypothesis but is contrary to the version of that hypothesis deemphasizing parasites. Tests of the new hypothesis are addressed

Are there adaptations for human microbiome inheritance and maintenance?

<p>Poses the question about adaptations for the inheritance and maintenance of the human microbiome. Was presented at Exploring Human Host-Microbiome Interactions in Health and Disease 29 June – 1 July 2015, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK.</p

USA Infectious Disease Transmission Data (corrected)

<div>This is a correction to the data published in Thornhill and Fincher (2014) in Appendix 3 of Section 5.25, pages 163-165. We redid the calculation of the nonzoonotic in the following way. We determined the population-adjusted case rate for the different transmission categories: human specific, multi-host, and zoonotic. Then we summed the case rates for the human specific and multi-host diseases to represent “nonzoonotic”. Then we standardised this new ’nonzoonotic’ value for each year and then averaged this z-score across the years for each state. The error in the prior, published data found in Thornhill and Fincher (Appendix 3 of section 5.25) was that we standardised the human specific and multi-host and then summed the z-scores which gives the multi-host scores too much undue influence. E.g., let’s say the human specific diseases had something like 2000 cases for a state and the multihost diseases had only 20 cases, if you z-score them separately you could have the same z-score for the human specific and the multihost for that state (e.g., each could get 1.2). If you then add these two together (2.4) you get a different score than if you added all the cases together (human specific cases + multi-host cases) and then z-scored the state values. In this new data file (USA_Transmission_Data_corrected.xlsx), we standardised the values after we summed them, correcting the problem. The human specific, multi-host, and zoonotic values in this 'USA_Transmission_Data_corrected.xlsx' file are identical to that published in Thornhill and Fincher (2014). Also, this spreadsheet includes both “with DC” and “without DC” data. We tend to use the “without DC” data unless there’s a strong reason to include it.</div><div><br></div><div>Thornhill, R., & Fincher, C. L. (2014). The parasite-stress theory of values and sociality: Infectious disease, history and human values worldwide. Springer.</div

Does infectious disease cause global variation in the frequency of intrastate armed conflict and civil war?

Geographic and cross-national variation in the frequency of intrastate armed conflict and civil war is a subject of great interest. Previous theory on this variation has focused on the influence on human behaviour of climate, resource competition, national wealth, and cultural characteristics. We present the parasite-stress model of intrastate conflict, which unites previous work on the correlates of intrastate conflict by linking frequency of the outbreak of such conflict, including civil war, to the intensity of infectious disease across countries of the world. High intensity of infectious disease leads to the emergence of xenophobic and ethnocentric cultural norms. These cultures suffer greater poverty and deprivation due to the morbidity and mortality caused by disease, and as a result of decreased investment in public health and welfare. Resource competition among xenophobic and ethnocentric groups within a nation leads to increased frequency of civil war. We present support for the parasite-stress model with regression analyses. We find support for a direct effect of infectious disease on intrastate armed conflict, and support for an indirect effect of infectious disease on the incidence of civil war via its negative effect on national wealth. We consider the entanglements of feedback of conflict into further reduced wealth and increased incidence of disease, and discuss implications for international warfare and global patterns of wealth and imperialism