An evolutionary behaviorist perspective on orgasm

Evolutionary explanations for sexual behavior and orgasm most often posit facilitating reproduction as the primary function (i.e. greater rate of fertilization). Other reproductive benefits of sexual pleasure and orgasm such as improved bonding of parents have also been discussed but not thoroughly. Although sex is known to be highly reinforcing, behaviorist principles are rarely invoked alongside evolutionary psychology in order to account for human sexual and social behavior. In this paper, I will argue that intense sexual pleasure, especially orgasm, can be understood as a primary reinforcer shaped by evolution to reinforce behavior that facilitates reproductive success (i.e. conception through copulation). Next, I will describe an evolutionary account of social shaping. In particular, I will focus on how humans evolved to use orgasm and sexual arousal to shape the social behavior and emotional states of others through both classical and operant conditioning and through both reproductive and non-reproductive forms of sexual behavior. Finally, I will describe how orgasm is a signal of sensitivity to reinforcement that is itself reinforcing

Menstrually related mood disorders and a history of abuse:moderators of pain sensitivity.

Objective. Women with menstrually related mood disorders (MRMD) have substantial rates of physical and sexual abuse, are more sensitive to experimental pain stimuli than women without MRMD, and endorse increased sensitivity to interpersonal rejection (emotional pain) in the premenstrual phase. For the first time, this study examined physical and emotional pain sensitivity in women with MRMD and in non-MRMD controls as a function of abuse history. Methods. A total of 126 women (63 MRMD, 34 with an abuse history and 63 non-MRMD, 31 with an abuse history) were evaluated for: (1) sensitivity to cold pressor and forearm ischemic pain; (2) emotional pain sensitivity based on daily prospective ratings of sensitivity to interpersonal rejection; and (3) basal plasma cortisol and norepinephrine (NE) concentrations. Exploratory analyses examined relationships between plasma cortisol and NE concentrations and physical pain sensitivity. Results. Women with MRMD and an abuse history showed increased sensitivity to both cold pressor and ischemic pain and lower basal cortisol concentrations, an effect not seen in the non-MRMD women. However, non-MRMD women with an abuse history showed increased sensitivity to emotional pain relative to non-MRMD women with no such history. In all subjects, the expected relationship between greater plasma cortisol concentration and reduced sensitivity to physical pain was observed. While only in women with MRMD, plasma NE predicted pain sensitivity. Conclusions. MRMD status moderates the effect of a history of abuse on both physical and emotional pain sensitivity. The results also suggest that the hypocortisolemia documented in the women with MRMD and an abuse history may contribute to their greater sensitivity to noxious experimental stimuli. This study adds to a growing body of evidence suggesting that a history of abuse may identify a clinically distinct subgroup of women with MRMD

Testing the affiliation hypothesis of homoerotic motivation in humans:the effects of progesterone and priming

The frequency of homoerotic behavior among individuals who do not identify as having an exclusively homosexual sexual orientation suggests that such behavior potentially has adaptive value. Here, we define homoerotic behavior as intimate erotic contact between members of the same sex and affiliation as the motivation to make and maintain social bonds. Among both male and female nonhuman primates, affiliation is one of the main drivers of homoerotic behavior. Correspondingly, in humans, both across cultures and across historical periods, homoerotic behavior appears to play a role in promoting social bonds. However, to date, the affiliation explanation of human homoerotic behavior has not been adequately tested experimentally. We developed a measure of homoerotic motivation with a sample of 244 men and women. Next, we found that, in women (n = 92), homoerotic motivation was positively associated with progesterone, a hormone that has been shown to promote affiliative bonding. Lastly, we explored the effects of affiliative contexts on homoerotic motivation in men (n = 59), finding that men in an affiliative priming condition were more likely to endorse engaging in homoerotic behavior compared to those primed with neutral or sexual concepts, and this effect was more pronounced in men with high progesterone. These findings constitute the first experimental support for the affiliation account of the evolution of homoerotic motivation in humans

Sensor recorded changes in rates of hand washing with soap in response to the media reports of the H1N1 pandemic in Britain

Objectives To examine how the frequency of information regarding a real disease threat influences hand washing with soap. Design and setting The authors installed wireless devices in highway service station lavatories in England to record the proportion of individuals washing hands with soap from May 2009 to January 2010. Participants Participants were users of men's and women's toilets. Combined there was an average of 6800 participant entrances into the lavatories daily. Primary outcome measure The primary outcome measure is the proportion of soap usage to the number of entries into the lavatories. Results Hand-washing rates were positively related to both H1NI coverage in blogs and the news; however, these relationships were stronger for men than for women. Conclusions Hand washing with soap increases proportionally to the frequency of media key words related to H1N1. Women's hand washing was more strongly associated with incidence of media keywords than men's

Can ‘eugenics’ be defended?

In recent years, bioethical discourse around the topic of ‘genetic enhancement’ has become increasingly politicized. We fear that there has been too much focus on the semantic question of whether we should call - or in this case perhaps it would be better to say brand - particular practices and emerging bio-technologies such as CRISPR ‘eugenicist’ or ‘eugenic’, rather than the more philosophically important question of how we should view them from the perspective of ethics and policy. Here, we address the question of whether ‘eugenics’ can be defended and how proponents and critics of enhancement should engage with each othe

HTLV-1-Associated Adult T Cell Leukemia Lymphoma Presenting as Granulomatous Pneumocystis Jiroveci Pneumonia (PJP) and Hypercalcemia

BACKGROUND: Since the initial description of human T cell lymphotropic virus (HTLV-1), clusters of this infection have been detected globally. Unlike HIV infection, most patients infected with HTLV-1 remain asymptomatic throughout their lifetime. CASE REPORT: We report the case of a 39-year-old Afro-Caribbean man with HTLV-1 infection presenting as hypercalcemia and granulomatous pneumocystis jiroveci pneumonia. RESULTS: Interestingly, the hypercalcemia presented with normal parathyroid hormone–related protein and low 1,25 dihydroxyvitamin D levels, and the presence of pneumocystis jiroveci in the granulomas was diagnosed with transbronchial biopsy taken during bronchoscopy. HTLV-1-associated adult T cell leukemia lymphoma (ATLL) was diagnosed in this patient by bone marrow and lymph node biopsy. CONCLUSION: Increased bone resorption, likely cytokine-mediated, is the most likely mechanism of hypercalcemia in this patient. This is believed to be the first description of this type of reaction to pneumocystis jiroveci in a HTLV-1-infected ATLL patient

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

Genetic architecture of subcortical brain structures in 38,851 individuals

Subcortical brain structures are integral to motion, consciousness, emotions and learning. We identified common genetic variation related to the volumes of the nucleus accumbens, amygdala, brainstem, caudate nucleus, globus pallidus, putamen and thalamus, using genome-wide association analyses in almost 40,000 individuals from CHARGE, ENIGMA and UK Biobank. We show that variability in subcortical volumes is heritable, and identify 48 significantly associated loci (40 novel at the time of analysis). Annotation of these loci by utilizing gene expression, methylation and neuropathological data identified 199 genes putatively implicated in neurodevelopment, synaptic signaling, axonal transport, apoptosis, inflammation/infection and susceptibility to neurological disorders. This set of genes is significantly enriched for Drosophila orthologs associated with neurodevelopmental phenotypes, suggesting evolutionarily conserved mechanisms. Our findings uncover novel biology and potential drug targets underlying brain development and disease