Sunday, November 13, 2022

Present-day countries composed of citizens whose ancestors experienced a degree of “state-ness” in previous centuries should experience fewer homicides today; found less support for alternative channels (economic development or current state capacity)

Homicide and State History. John Gerring and Carl Henrik Knutsen. American Sociological Review, Nov 9 2022.

Abstract: We argue that cross-national variability in homicide rates is strongly influenced by state history. Populations living within a state are habituated, over time, to settling conflicts through regularized, institutional channels rather than personal violence. Because these are gradual and long-term processes, present-day countries composed of citizens whose ancestors experienced a degree of “state-ness” in previous centuries should experience fewer homicides today. To test this proposition, we adopt an ancestry-adjusted measure of state history that extends back to 0 CE. Cross-country analyses show a sizeable and robust relationship between this index and lower homicide rates. The result holds when using various measures of state history and homicide rates, sets of controls, samples, and estimators. We also find indicative evidence that state history relates to present levels of other forms of personal violence. Tests of plausible mechanisms suggest state history is linked to homicide rates via the law-abidingness of citizens. We find less support for alternative channels such as economic development or current state capacity.

Cephalopod retinal development shows vertebrate-like mechanisms of neurogenesis

Cephalopod retinal development shows vertebrate-like mechanisms of neurogenesis. Francesca R. Napoli et al. Current Biology, November 09, 2022.


• Retinal progenitor cells in the squid undergo interkinetic nuclear migration

• Progenitor, post-mitotic, and differentiated cells are transcriptionally defined

• Notch signaling may regulate both retinal cell cycle and cell fate in the squid

Summary: Coleoid cephalopods, including squid, cuttlefish, and octopus, have large and complex nervous systems and high-acuity, camera-type eyes. These traits are comparable only to features that are independently evolved in the vertebrate lineage. The size of animal nervous systems and the diversity of their constituent cell types is a result of the tight regulation of cellular proliferation and differentiation in development. Changes in the process of development during evolution that result in a diversity of neural cell types and variable nervous system size are not well understood. Here, we have pioneered live-imaging techniques and performed functional interrogation to show that the squid Doryteuthis pealeii utilizes mechanisms during retinal neurogenesis that are hallmarks of vertebrate processes. We find that retinal progenitor cells in the squid undergo nuclear migration until they exit the cell cycle. We identify retinal organization corresponding to progenitor, post-mitotic, and differentiated cells. Finally, we find that Notch signaling may regulate both retinal cell cycle and cell fate. Given the convergent evolution of elaborate visual systems in cephalopods and vertebrates, these results reveal common mechanisms that underlie the growth of highly proliferative neurogenic primordia. This work highlights mechanisms that may alter ontogenetic allometry and contribute to the evolution of complexity and growth in animal nervous systems.

Popular version: How squid and octopus get their big brains

Study finds differences in brain structure between boys and girls with binge eating disorders

Sex differences in regional gray matter density in pre-adolescent binge eating disorder: a voxel-based morphometry study. Stuart B. Murray et al. Psychological Medicine, October 28 2022. DOI: 10.1017/S0033291722003269


Background: Binge eating disorder (BED) is a pernicious psychiatric disorder which is linked with broad medical and psychiatric morbidity, and obesity. While BED may be characterized by altered cortical morphometry, no evidence to date examined possible sex-differences in regional gray matter characteristics among those with BED. This is especially important to consider in children, where BED symptoms often emerge coincident with rapid gray matter maturation.

Methods: Pre-adolescent, 9–10-year old boys (N = 38) and girls (N = 33) with BED were extracted from the 3.0 baseline (Year 0) release of the Adolescent Brain Cognitive Development Study. We investigated sex differences in gray matter density (GMD) via voxel-based morphometry. Control sex differences were also assessed in age and body mass index and developmentally matched control children (boys N = 36; girls N = 38). Among children with BED, we additionally assessed the association between dorsolateral prefrontal (dlPFC) GMD and parent-reported behavioral approach and inhibition tendencies.

Results: Girls with BED uniquely demonstrate diffuse clusters of greater GMD (p < 0.05, Threshold Free Cluster Enhancement corrected) in the (i) left dlPFC (p = 0.003), (ii) bilateral dmPFC (p = 0.004), (iii) bilateral primary motor and somatosensory cortex (p = 0.0003) and (iv) bilateral precuneus (p = 0.007). Brain-behavioral associations suggest a unique negative correlation between GMD in the left dlPFC and behavioral approach tendencies among girls with BED.

Conclusions: Early-onset BED may be characterized by regional sex differences in terms of its underlying gray matter morphometry.

Popular version: Study finds differences in brain structure between boys and girls with binge eating disorders. Nov 10 2022.

Adherence to emotion norms is greater in individualist cultures than in collectivist cultures; in the more individualist countries, deviation from the mean emotional experience was linked to lower life satisfaction

Adherence to emotion norms is greater in individualist cultures than in collectivist cultures. Vishkin, A., Kitayama, S., Berg, M. K., Diener, E., Gross-Manos, D., Ben-Arieh, A., & Tamir, M. (2022). Journal of Personality and Social Psychology, Nov 2022.

Abstract: It is generally assumed that there is greater pressure to conform to social norms in collectivist cultures than in individualist cultures. However, most research on cultural differences in social norms has examined norms for behaviors. Here, we examine cultural differences in norms for emotions. Relative to members of collectivist cultures, members of individualist cultures are more attuned to internal states and value them more. Therefore, we predicted that adherence to emotion norms would be greater in individualist than in collectivist cultures. In four studies with 119 samples from 69 distinct countries and over 200,000 participants, we estimated adherence to emotion norms in different cultures, and how deviation from emotion norms is associated with life satisfaction. As predicted, in countries higher in individualism, emotional experiences of individuals were more homogenous and more concordant with the emotions of others in their culture. Furthermore, in more individualist countries, deviation from the mean emotional experience was linked to lower life satisfaction. We discuss two complementary mechanisms that may underlie such differences.

Overall, research indicates that the risk of getting stuck in a filter bubble on intermediaries such as Google News, Apple News, Facebook, or Twitter is low and often exaggerated

News recommender systems: a programmatic research review. Eliza Mitova et al. Annals of the International Communication Association, Nov 11 2022.

Abstract: News recommender systems (NRS) are becoming a ubiquitous part of the digital media landscape. Particularly in the realm of political news, the adoption of NRS can significantly impact journalistic distribution, in turn affecting journalistic work practices and news consumption. Thus, NRS touch both the supply and demand of political news. In recent years, there has been a strong increase in research on NRS. Yet, the field remains dispersed across supply and demand research perspectives. Therefore, the contribution of this programmatic research review is threefold. First, we conduct a scoping study to review scholarly work on the journalistic supply and user demand sides. Second, we identify underexplored areas. Finally, we advance five recommendations for future research from a political communication perspective.

Keywords: News recommender systemsalgorithmsdigital journalismnews personalisation

Overall, research indicates that the risk of getting stuck in such a bubble on intermediaries such as Google News (e.g. Evans et al., 2022; Haim et al., 2018; Nechushtai & Lewis, 2019), Apple News (e.g. Bandy & Diakopoulos, 2020), Facebook (e.g. Bakshy et al., 2015; Beam et al., 2018; Bechmann & Nielbo, 2018; Moeller et al., 2016; Papa & Photiadis, 2021; but see Levy, 2021 for divergent findings), or Twitter (e.g. Bandy & Diakopoulos, 2021; Chen et al., 2021; but see Jürgens & Stark, 2022 for divergent findings) is low and often exaggerated

Similarity in physical attractiveness did not play a role in spousal relationship satisfaction & maintenance

Pávez, P., Polo, P., Valenzuela, N., Figueroa, O., Rodríguez-Sickert, C., & Muñoz-Reyes, J. A. (2022). Similarity in Indicators of Attractiveness in Heterosexual Couples, and their Relationship with Satisfaction and Trust. Psykhe.

Abstract: In our species, the formation and maintenance of romantic partners is a nonrandom process. In this sense, similarity between members of the couple can be relevant for the beginning of the relationship (i.e., assortative mating) and maintenance, being similarity in attractiveness one of the most interesting aspects of this phenomenon. Despite that similarity in attractive traits has been documented, there is a lack of studies including modern morphological measures like fluctuating facial asymmetry or body fat percentage when assessing the effect that similarity in attractiveness could provoke on behaviors and feelings necessary to maintain a long-term relationship (e.g., satisfaction and trust). We assessed the presence of similarity in attractiveness for self-perceived measures (attractiveness and mate value) and physical traits (body fat percentage, body mass index, and fluctuating facial asymmetry) in a population of 196 heterosexual young couples from Chile (n = 392). Then, using actor-partner interdependence models (APIM), we assessed whether satisfaction and trust within the couples were influenced by attractiveness. Our results indicated the presence of similarity for all studied traits with the exception of fluctuating facial asymmetry. In addition, we only found that self-assessment of attractiveness is important for satisfaction in women, and partner's physical attractiveness is important for satisfaction and trust in men. Our results suggest that similarity in attractiveness is not playing a major role in affecting relationship. It is probably that similarity could be better explained from the initial stages of relationship, where the mating market forces conduce to the conformation of similar couples.