Impacts of farming in Neolithic Çatalhöyük community
Neolithic burial from Çatalhöyük, Turkey; a headless young adult female with a fetal skeleton (arrow). Image courtesy of the Çatalhöyük Research Project/Jason Quinlan.
Humans began transitioning from foraging to farming around 10,000–11,000 years ago. Health and lifestyle changes experienced by early farmers are unclear, partly because archaeological records are incomplete. Clark Spencer Larsen et al. (pp. 12615–12623) conducted a bioarchaeological investigation of Çatalhöyük, a Neolithic archaeological site in Turkey that enabled detailed analyses of the landscape as well as animal and plant remains. The authors focused on 742 human remains dating from 7100 to 5950 BCE. For the inhabitants of Çatalhöyük, transitioning to farming increased exposure to diseases. Higher birth rates led to a growing population, with a peak of approximately 3,500–8,000 individuals. As the community grew, labor demands and the need to acquire food increased. Crowded living conditions contributed to interpersonal violence, as indicated by cranial injuries, as well as increased risk of infection and pathogen transmission. Sheep, which are intermediate hosts to several human parasites, posed a major public health concern. Consumption of plant carbohydrates as well as bread and porridge led to dental problems. Material culture, including wall paintings and figurines, illustrated the evolution of a complex society, and ancestral graves beneath house floors attested to a prevailing sense of community. According to the authors, the findings at Çatalhöyük provide insight into how human lifestyles evolved over the following millennia. — M.S.
Medical cannabis and opioid overdose
Cannabis being grown for medicinal use. Image courtesy of Wikimedia Commons/Zoboar.
Previous research has reported reduced mortality rates from opioid overdose in US states with medical cannabis laws between 1999 and 2010. The finding has been cited as proof that medical cannabis legalization will prevent opioid overdose deaths, despite cautionary notes against drawing causal conclusions from ecological correlations. Chelsea Shover et al. (pp. 12624–12626) used the same methods used in the earlier work to extend the available data through 2017. For the years 1999–2010, the authors found a 21% decrease in opioid overdose mortality associated with medical cannabis laws, in agreement with the earlier finding. However, when the data through 2017 were included in the analysis, the association between medical cannabis laws and overdose mortality changed from negative to positive, with implementation of a law associated with a 23% increase in mortality on average. The association remained positive even after controlling for different types of cannabis laws, and neither recreational nor low-THC cannabis laws were associated with changes in opioid overdose mortality. According to the authors, the observed associations between medical cannabis laws and opioid overdose mortality may be spurious, given that only around 2.5% of the US population uses medical cannabis. — B.D.
Developmental pathways influencing male sexual orientation
Rainbow flag symbolizing LGBT pride. Image courtesy of Pixabay/QuinceMedia.
Various biomarkers are associated with male sexual orientation, suggesting possible underlying immunological, endocrine, and genetic mechanisms. However, the biomarkers have been studied in isolation, and the extent to which they interact or overlap remains unclear. Ashlyn Swift-Gallant et al. (pp. 12787–12792) used a method called latent profile analysis to examine the distribution of 3 established biomarkers of sexual orientation—number of older brothers, left-handedness, and familiality of same-sex orientation—in more than 800 men, 18 years of age and older. The analysis identified 4 subpopulations within the sample, which could be distinguished based on the biomarkers. None of the biomarkers were elevated among men in the first subgroup, whereas each of the remaining subgroups exhibited elevated levels for only one of the biomarkers. The biomarker that was elevated differed for each subgroup. The 3 subgroups with elevated biomarker levels each had a higher proportion of nonheterosexual men compared with the subgroup that did not exhibit any elevated biomarker levels. The four subgroups differed significantly with respect to measures of gender nonconformity and personality traits such as femininity and agreeableness. The results suggest the existence of subgroups of nonheterosexual men whose sexual orientation may be associated with different biological mechanisms, according to the authors. — B.D.
Similarities between romantic partners
Romantic relationships have significant impacts on well-being, but the degree to which individuals are paired with partners who have similar personalities across relationships is unclear. Yoobin Park and Geoff MacDonald (pp. 12793–12797) analyzed personality similarities between individuals’ current and ex-partners via longitudinal data from the German Family Panel study. Beginning in 2008, the authors tracked the participants’ relationship statuses. From the following year and each time a participant entered a new relationship, their romantic partner, who agreed to participate in the study, described their own personality traits related to agreeableness, conscientiousness, extraversion, neuroticism, and openness to experience. By 2017, 332 participants had dated two different partners who completed the personality assessments. Overall, participants’ current partners described their personalities in ways that were similar to the participants as well as the participants’ ex-partners. The authors also found evidence suggesting that participants who rated themselves high in extraversion and/or openness to experience were less likely to date current partners who were similar to their ex-partners. According to the authors, the findings suggest that individuals tend to date people with similar personalities, and partnering patterns may be more predictable than thought. — M.S.
Evolution of night vision
Western tarsier.
The pigment rhodopsin, present in rod cells of the retina, enables vision in low-light conditions, also called scotopic vision, and allows vertebrates to occupy a diverse range of light-level niches. The properties of ancestral rhodopsins, from the base of major vertebrate lineages, are poorly understood. Yang Liu et al. (pp. 12627–12628) reconstructed ancestral rhodopsins from major vertebrate lineages, exposed the reconstructed pigments to light, and measured the pigments’ rates of decay. A slow rate of decay or a long half-life implies an extended signaling state and high adaptation to low-light conditions. The authors report that the common ancestor of all vertebrates had a rhodopsin half-life of around 3 minutes, with shifts toward longer half-lives occurring with the rise of bony fishes and tetrapods. Early tetrapods and amniotes were likely nocturnal, although the first mammals may have occupied both nocturnal and dawn/dusk niches. Dinosaurs appear to have evolved from a nocturnal ancestor, whereas the earliest birds were probably adapted to bright light. According to the authors, the results suggest that advanced adaptation to low-light conditions likely occurred during the early evolution of tetrapods. — P.G.
Early alcohol production in Neolithic China
Globular jar fitted with a funnel-steamer in the Baoji Museum in Shaanxi province, China.
Previous studies have found that the diversity of specialized pottery containers in China increased between around 7,000 and 9,000 years ago and that Chinese people developed an early form of alcohol. However, the link between the 2 findings has not been explored. Li Liu et al. (pp. 12767–12774) analyzed food residue adhering to the interior surfaces of Neolithic pottery vessels dating to between 7,000 and 8,000 years ago. The authors found traces of starch, phytoliths, and fungi, suggesting that the pottery contained alcoholic beverages. According to the authors, a series of developments led to the proliferation of alcohol production in Neolithic China. The first development was the spread of cereal domestication, including millets and rice, which were likely the primary ingredients of fermented beverages. The second advance was the development of globular pottery jars as storage containers, and the third advance was the development of 2 distinct methods for alcohol production. One of the methods used cereal malts as a fermentation starter, and another method used moldy grains and herbs as starters. Additional plants that may have been used as ingredients include Triticeae, Job’s tears, snake gourd root, ginger, yam, and lily. The resulting product was likely a low-alcohol beverage. According to the authors, the results extend and deepen the history of alcohol production in Neolithic China. — P.G.
Single nanoparticle dynamics and smart window tinting
Single nanoparticles tint one by one in a smart window device. Image courtesy of Steven Marquez (Colorado State University, Fort Collins, CO).
Smart windows transition between transparent and tinted states by using small voltages to drive ions into or out of transparent tungsten oxide thin films. Although smart glass offers numerous advantages related to energy consumption and human comfort, the technology is currently hampered by slow tinting rates, around 7–12 minutes. R. Colby Evans et al. (pp. 12666–12671) demonstrate the use of single-particle-resolution optical imaging to measure structure–function relationships in tungsten oxide nanorods, a nanomaterial with properties that can potentially enable rapid tinting. The authors show that single nanorods undergo a particle-dependent delay prior to tinting, an initial waiting period required to insert lithium ions at optically inactive surface sites. Further, the delay contributes to the inefficiency of nanoparticle films and a nonuniform tinting appearance that spreads in space and time as particles switch one by one. The study also reveals that interfaces between particles act as ion traps that gradually degrade the optical performance of the material. Based on these measurements and additional findings showing that single particles tint up to 4 times faster and cycle more reliably than films, the authors present a thin-film architecture. The thin film is designed to exploit fast-switching electrochromic nanoparticles and avoid detrimental particle-to-particle interactions, according to the authors. — T.J.