People who were bitten by a snake (either venomous or not) scored lower in fear of snakes; people could become fear immunized even against highly biologically prepared fearful stimuli

Coelho, Carlos M., Panrapee Suttiwan, and Andras N. Zsido. 2019. “Fear Inoculation Among Snake Experts.” PsyArXiv. August 24. doi:10.31234/osf.io/ph5ug

Abstract: Prepared phobias are often seen as acquired rapidly, generalize broadly and are resistant to extinction. Nonetheless provided opportunity for innocuous contact with certain kinds of stimuli people tend to show less fear when compared with others who never or rarely deal with the same stimuli. This study finds that people who were bitten by a snake (either venomous or not) scored lower in fear of snakes, as measured by the SNAQ-12, and SPQ surveys. These fearless people also have more experience with snakes than those who were not bitten. Results suggest that people could become immunized even against highly biologically prepared fearful stimuli, such as snakes, after a certain amount of previous benign exposure. We stress that lack of fear might bring people to become unworried and develop extreme risk of snakebite envenomation, which has recently (2017) been classified by the World Health Organization as a category A neglected tropical disease.

Sexual narcissism was positively associated with sexual functioning in both women and men; in the women's sample, sexual narcissism was related to a positive genital self-image

Sexual narcissism and its association with sexual and well-being outcomes. Verena Klein et al. Personality and Individual Differences, Volume 152, 1 January 2020, 109557. https://doi.org/10.1016/j.paid.2019.109557

Abstract: Theories on narcissism are traditionally closely related to sexuality. Most research on the association between narcissism and sexual behavior, however, has focused on harmful/maladaptive outcomes. The aim of the present two studies was to examine the possible health-promoting influence of both global and sexual narcissism on sexual function and genital self-image. In Study 1, sexual narcissism was positively associated with sexual functioning in both women and men (N = 505, online-recruited German participants). In the women's sample, sexual narcissism was related to a positive genital self-image. The facet sexual skill was identified as the most important predictor for sexual function and positive genital self-image in both women and men. Study 2 replicated and extended this association in an online sample of US Americans (N = 588) by including quality of life measures. Underscoring the benign nature of the sexual skill facet, this subscale was associated with quality of life in both women and men. The idea of a possible beneficial influence of sexual narcissism on sexuality related outcomes is discussed.

Keywords: Sexual narcissismNarcissismGenital self-imageSexual functionSexual health

Sexual experience has no effect on male mating or reproductive success in house mice

Sexual experience has no effect on male mating or reproductive success in house mice. Kerstin E. Thonhauser, Alexandra Raffetzeder & Dustin J. Penn. Scientific Reports, August 21 2019, volume 9, 12145 (2019). https://www.nature.com/articles/s41598-019-48392-x

Abstract: The ability to learn from experience can improve Darwinian fitness, but few studies have tested whether sexual experience enhances reproductive success. We conducted a study with wild-derived house mice (Mus musculus musculus) in which we manipulated male sexual experience and allowed females to choose between (1) a sexually experienced versus a virgin male, (2) two sexually experienced males, or (3) two virgin males (n = 60 females and 120 males). This design allowed us to test whether females are more likely to mate multiply when they encounter more virgin males, which are known to be infanticidal. We recorded females’ preference and mating behaviours, and conducted genetic paternity analyses to determine male reproductive success. We found no evidence that sexual experience influenced male mating or reproductive success, and no evidence that the number of virgin males influenced female multiple mating. Females always copulated with both males and 58% of the litters were multiple-sired. Females’ initial attraction to a male correlated with their social preferences, but neither of these preference behaviours predicted male reproductive success – raising caveats for using mating preferences as surrogates for mate choice. Male reproductive success was predicted by mating order, but unexpectedly, males that copulated first sired fewer offspring.

“Daddies,” “Cougars”, & Relationship and Sexual Well-Being among Older Adults & Young Lovers: Women partnered to older men had less sex and more issues related to sexual satisfaction

“Daddies,” “Cougars,” and Their Partners Past Midlife: Gender Attitudes and Relationship and Sexual Well-Being among Older Adults in Age-Heterogenous Partnerships. Tony Silva. Socius: Sociological Research for a Dynamic World, August 19, 2019. https://doi.org/10.1177/2378023119869452

Abstract: Discussion of “daddies” has exploded in popular discourse, yet there is little sociological research on age-heterogenous partnerships. This paper uses data from the 2013 Midlife in the United States survey and the 2015–2016 National Social Life, Health, and Aging Project to examine age-heterogenous partnerships at older ages (63 was the approximate average age of each sample). On most measures of life satisfaction and relationship well-being, individuals in age-heterogenous partnerships—regardless of age or gender—were not very different from their counterparts in age-homogenous relationships. Some differences did emerge, however, especially related to sexual well-being. Women partnered to older men had less sex and more issues related to sexual satisfaction than their counterparts in age-homogenous relationships. Latent class analyses suggest that these differences were driven by around 40 percent of younger women partnered to older men, a minority of whom were deeply dissatisfied. This research helps address the underrepresentation of sexuality research at older ages and the sociological research gap about age-heterogenous partnerships.

Keywords: sexuality, gender, age-heterogenous partnership, daddy, cougar

Absolute and relative estimates of genetic and environmental variance in brain structure volumes

Absolute and relative estimates of genetic and environmental variance in brain structure volumes. Lachlan T. Strike et al. Brain Structure and Function, August 19 2019. https://link.springer.com/article/10.1007/s00429-019-01931-8

Abstract: Comparing estimates of the amount of genetic and environmental variance for different brain structures may elucidate differences in the genetic architecture or developmental constraints of individual brain structures. However, most studies compare estimates of relative genetic (heritability) and environmental variance in brain structure, which do not reflect differences in absolute variance between brain regions. Here we used a population sample of young adult twins and singleton siblings of twins (n = 791; M = 23 years, Queensland Twin IMaging study) to estimate the absolute genetic and environmental variance, standardised by the phenotypic mean, in the size of cortical, subcortical, and ventricular brain structures. Mean-standardised genetic variance differed widely across structures [ 23.5-fold range 0.52% (hippocampus) to 12.28% (lateral ventricles) ], but the range of estimates within cortical, subcortical, or ventricular structures was more moderate (two to fivefold range). There was no association between mean-standardised and relative measures of genetic variance (i.e., heritability) in brain structure volumes. We found similar results in an independent sample (n = 1075, M = 29 years, Human Connectome Project). These findings open important new lines of enquiry: namely, understanding the bases of these variance patterns, and their implications regarding the genetic architecture, evolution, and development of the human brain.

Keywords: Volume Genetics Magnetic resonance imaging Twins

Radical lifespan disparities exist in the animal kingdom: Revamping the Evolutionary Theories of Aging

Revamping the Evolutionary Theories of Aging. Adiv A. Johnsona, Maxim N. Shokhirev, Boris Shoshitaishvili. Ageing Research Reviews, August 23 2019, 100947. https://doi.org/10.1016/j.arr.2019.100947

Highlights
• Extrinsic mortality is one of the most important drivers in the evolution of aging.
• Classical predictions expect higher extrinsic mortality to shorten evolved lifespan.
• The bulk of published data conform to the classical evolutionary theories of aging.
• Increased extrinsic mortality can sometimes select for longer evolved lifespans.
• Immortal animals that experience extrinsic mortality challenge classical theories.
• The aging response to extrinsic mortality involves multiple interacting factors.

Abstract: Radical lifespan disparities exist in the animal kingdom. While the ocean quahog can survive for half a millennium, the mayfly survives for less than 48 hours. The evolutionary theories of aging seek to explain why such stark longevity differences exist and why a deleterious process like aging evolved. The classical mutation accumulation, antagonistic pleiotropy, and disposable soma theories predict that increased extrinsic mortality should select for the evolution of shorter lifespans and vice versa. Most experimental and comparative field studies conform to this prediction. Indeed, animals with extreme longevity (e.g., Greenland shark, bowhead whale, giant tortoise, vestimentiferan tubeworms) typically experience minimal predation. However, data from guppies, nematodes, and computational models show that increased extrinsic mortality can sometimes lead to longer evolved lifespans. The existence of theoretically immortal animals that experience extrinsic mortality – like planarian flatworms, panther worms, and hydra – further challenges classical assumptions. Octopuses pose another puzzle by exhibiting short lifespans and an uncanny intelligence, the latter of which is often associated with longevity and reduced extrinsic mortality. The evolutionary response to extrinsic mortality is likely dependent on multiple interacting factors in the organism, population, and ecology, including food availability, population density, reproductive cost, age-mortality interactions, and the mortality source.

Keywords: evolution of agingmutation accumulationantagonistic pleiotropydisposable somalifespanextrinsic mortality

However, since radical people represent only 20% of the population and there was no effect for Facebook or blogs, the overall effect of the Internet was moderation, not polarization

Tatsuo Tanaka, 2019. "Does the Internet cause polarization? -Panel survey in Japan-," Keio-IES Discussion Paper Series 2019-015, Institute for Economics Studies, Keio University. https://ideas.repec.org/p/keo/dpaper/2019-015.html

Abstract: There is concern that the Internet causes ideological polarization through selective exposure and the echo chamber effect. This paper examines the effect of social media on polarization by applying a difference-in-difference approach to panel data of 50 thousand respondents in Japan. Japan is good case for this research because other factors affecting polarization like huge wealth gap and massive immigration are not serious issue, thus it offers quasi natural experimental situation to test the effect of the Internet. The results show that people who started using social media during the research period (targets) were no more polarized than people who did not (controls). There was a tendency for younger and politically moderate people to be less polarized. The only case in which the Internet increased polarization was for already radical people who started using Twitter. However, since radical people represent only 20% of the population and there was no effect for Facebook or blogs, the overall effect of the Internet was moderation, not polarization.

Check also... Explaining the Spread of Misinformation on Social Media: Evidence from the 2016 U.S. Presidential Election. Pablo Barbera. Note prepared for the APSA Comparative Politics Newsletter, Fall 2018.  https://www.bipartisanalliance.com/2019/06/ironically-it-may-not-be-much-trumpeted.html

And Testing popular news discourse on the “echo chamber” effect: Does political polarisation occur among those relying on social media as their primary politics news source? An Nguyen, Hong Tien Vu. First Monday, Volume 24, Number 6 - 3 June 2019.
https://www.bipartisanalliance.com/2019/06/does-political-polarisation-occur-among.html

Growing body of evidence suggests that inconsistent hand preference is indicative of an increased disposition to update one’s beliefs upon exposure to novel information; this seems wrong

M. L., Vilsmeier, J. K., Voracek, M., & Tran, U. S. (2019). No Evidence That Lateral Preferences Predict Individual Differences in the Tendency to Update Mental Representations: A Replication-Extension Study. Collabra: Psychology, 5(1), 38. DOI: http://doi.org/10.1525/collabra.227

Abstract: A growing body of evidence suggests that inconsistent hand preference is indicative of an increased disposition to update one’s beliefs upon exposure to novel information. This is attributed to a facilitated exchange of information between the two brain hemispheres among inconsistent handers, compared to consistent handers. Currently available studies provide only indirect evidence for such an effect, were mostly based on small sample sizes, and did not provide measures of effect size. Small sample size is a major factor contributing to low replicability of research findings and false-positive results. We thus attempted to replicate Experiment 1 of Westfall, Corser and Jasper (2014), which appears to be representative of research on degree of handedness and belief updating in terms of the employed methods. We utilized data from a sample more than 10 times the size (N = 1243) of the original study and contrasted the commonly applied median-split technique to classify inconsistent and consistent handers with an empirically grounded classification scheme. Following a replication-extension approach, besides handedness, footedness was also explored. Only one out of 12 chi-squared tests reached significance and supported the original hypothesis that inconsistent handers stay with, or switch more often from, the status quo than consistent handers, depending on the valence of novel information. A small-telescopes analysis suggested that the original study had too low analytic power to detect its reported effect reliably. These results cast doubt on the assumption that inconsistent and consistent-handers differ in the tendency to update mental representations. We discuss the use of the median-split technique in handedness research, available neuroscientific evidence on interhemispheric interaction and inconsistent handedness, and venues of future research.

Keywords: Handedness ,   Degree-of-handedness ,   Footedness ,   Status Quo Bias ,   Lateral Preference Classification