The Inevitability of Ethnocentrism Revisited: Ethnocentrism Diminishes As Mobility Increases

Algorithm-mediated social learning in online social networks

Human social learning is increasingly occurring on online social platforms, such as Twitter, Facebook, and TikTok. On these platforms, algorithms exploit existing social-learning biases (i.e., towards prestigious, ingroup, moral, and emotional information, or 'PRIME' information) to sustain users' attention and maximize engagement. Here, we synthesize emerging insights into 'algorithm-mediated social learning' and propose a framework that examines its consequences in terms of functional misalignment. We suggest that, when social-learning biases are exploited by algorithms, PRIME information becomes amplified via human-algorithm interactions in the digital social environment in ways that cause social misperceptions and conflict, and spread misinformation. We discuss solutions for reducing functional misalignment, including algorithms promoting bounded diversification and increasing transparency of algorithmic amplification.

Pancreatic RECK inactivation promotes cancer formation, epithelial-mesenchymal transition, and metastasis

RECK is downregulated in various human cancers; however, how RECK inactivation affects carcinogenesis remains unclear. We addressed this issue in a pancreatic ductal adenocarcinoma (PDAC) mouse model and found that pancreatic Reck deletion dramatically augmented the spontaneous development of PDAC with a mesenchymal phenotype, which was accompanied by increased liver metastases and decreased survival. Lineage tracing revealed that pancreatic Reck deletion induced epithelial-mesenchymal transition (EMT) in PDAC cells, giving rise to inflammatory cancer-associated fibroblast-like cells in mice. Splenic transplantation of Reck-null PDAC cells resulted in numerous liver metastases with a mesenchymal phenotype, whereas reexpression of RECK markedly reduced metastases and changed the PDAC tumor phenotype into an epithelial one. Consistently, low RECK expression correlated with low E-cadherin expression, poor differentiation, metastasis, and poor prognosis in human PDAC. RECK reexpression in the PDAC cells was found to downregulate MMP2 and MMP3, with a concomitant increase in E-cadherin and decrease in EMT-promoting transcription factors. An MMP inhibitor recapitulated the effects of RECK on the expression of E-cadherin and EMT-promoting transcription factors and invasive activity. These results establish the authenticity of RECK as a pancreatic tumor suppressor, provide insights into its underlying mechanisms, and support the idea that RECK could be an important therapeutic effector against human PDAC.

The Cultural Boundaries of Perspective-Taking: When and Why Perspective-Taking Reduces Stereotyping

Research conducted in Western cultures indicates that perspective-taking is an effective social strategy for reducing stereotyping. The current article explores whether and why the effects of perspective-taking on stereotyping differ across cultures. Studies 1 and 2 established that perspective-taking reduces stereotyping in Western but not in East Asian cultures. Using a socioecological framework, Studies 2 and 3 found that relational mobility, that is, the extent to which individuals' social environments provide them opportunities to choose new relationships and terminate old ones, explained our effect: Perspective-taking was negatively associated with stereotyping in relationally mobile (Western) but not in relationally stable (East Asian) environments. Finally, Study 4 examined the proximal psychological mechanism underlying the socioecological effect: Individuals in relationally mobile environments are more motivated to develop new relationships than those in relationally stable environments. Subsequently, when this motivation is high, perspective-taking increases self-target group overlap, which then decreases stereotyping.

The abolition of war as a goal of environmental policy

Since the 1950s, select military and political leaders have had the capacity to kill all or nearly all human life on Earth. The number of people entrusted with this power grows each year through proliferation and the rise of new political leaders. If humans continue to maintain and develop nuclear weapons, it is highly probable that a nuclear exchange will occur again at some point in the future. This nuclear exchange may or may not annihilate the human species, but it will cause catastrophic effects on the biosphere. The international community has attempted to resolve this existential problem via treaties that control and potentially eliminate nuclear weapons, however, these treaties target only nuclear weapons, leaving the use of war as a normalized means for settling conflict. As long as war exists as a probable future, nations will be under pressure to develop more powerful weapons. Thus, we argue that the elimination of nuclear weapons alone is not a stable, long-term strategy. A far more secure strategy would be the elimination of war as a means of settling international disputes. Therefore, those concerned about environmental sustainability or the survival of the biosphere should work to abolish war.

Investigating the Evolution of Ingroup Favoritism Using a Minimal Group Interaction Paradigm: The Effects of Inter- and Intragroup Interdependence

We investigated the effect of structural interdependencies between groups (especially inequality), and interdependencies between individuals on ingroup favoritism in minimal group situations. Previous research has attempted to determine whether ingroup favoritism is produced by categorization or intragroup interdependencies (reciprocation expectations), but recent literature suggests that it is not possible to tease these influences apart. We report two studies that investigate how ingroup favoritism evolves over time in social interaction. The levels of ingroup favoritism were affected by categorization and inequality, and the level of ingroup favoritism changed over time, increasing or decreasing depending on the nature of the initial intergroup structure. We conclude by providing two explanations for this change: emergent norms, and changes to the intergroup situation produced by interaction. Our experiments confirm the value of studying the evolution of minimal group behavior, especially for explaining why low status groups act to preserve intergroup inequalities.

Characterisation of a phantom for multiwavelength quantitative photoacoustic imaging

Quantitative photoacoustic imaging (qPAI) has the potential to provide high- resolution in vivo images of chromophore concentration, which may be indicative of tissue function and pathology. Many strategies have been proposed recently for extracting quantitative information, but many have not been experimentally verified. Experimental phantom-based validation studies can be used to test the robustness and accuracy of such algorithms in order to ensure reliable in vivo application is possible. The phantoms used in such studies must have well-characterised optical and acoustic properties similar to tissue, and be versatile and stable. Polyvinyl chloride plastisol (PVCP) has been suggested as a phantom for quality control and system evaluation. By characterising its multiwavelength optical properties, broadband acoustic properties and thermoelastic behaviour, this paper examines its potential as a phantom for qPAI studies too. PVCP's acoustic properties were assessed for various formulations, as well as its intrinsic optical absorption, and scattering with added TiO2, over a range of wavelengths from 400-2000 nm. To change the absorption coefficient, pigment-based chromophores that are stable during the phantom fabrication process, were used. These yielded unique spectra analogous to tissue chromophores and linear with concentration. At the high peak powers typically used in photoacoustic imaging, nonlinear optical absorption was observed. The Grüneisen parameter was measured to be [Formula: see text]  =  1.01  ±  0.05, larger than typically found in tissue, though useful for increased PA signal. Single and multiwavelength 3D PA imaging of various fabricated PVCP phantoms were demonstrated.