Why does human culture increase exponentially?

Historical records show that culture can increase exponentially in time, e.g., in number of poems, musical works, scientific discoveries. We model how human capacities for creativity and cultural transmission may make such increase possible, suggesting that: 1) creativity played a major role at the origin of human culture and for its accumulation throughout history, because cultural transmission cannot, on its own, generate exponentially increasing amounts of culture; 2) exponential increase in amount of culture can only occur if creativity is positively influenced by culture. The evolution of cultural transmission is often considered the main genetic bottleneck for the origin of culture, because natural selection cannot favor cultural transmission without any culture to transmit. Our models suggest that an increase in individual creativity may have been the first step toward human culture, because in a population of creative individuals there may be enough non-genetic information to favor the evolution of cultural transmission

Clinical validation of immunoglobulin A nephropathy diagnosis in Swedish biopsy registers

Simon Jarrick,1,2 Sigrid Lundberg,3,4 Adina Welander,5,6 C Michael Fored,6 Jonas F Ludvigsson2,7,8 1Department of Pediatrics, Faculty of Health and Medicine, Örebro University, 2Department of Pediatrics, Örebro University Hospital, Örebro, 3Department of Nephrology, Karolinska University Hospital, 4Department of Clinical Science, Intervention and Technology, Karolinska Institutet, 5Boston Consulting Group, 6Clinical Epidemiology Unit, Department of Medicine, 7Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; 8Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK Aims: The aims of this study were to validate the diagnosis of IgA nephropathy (IgAN) in Swedish biopsy registers against patient charts and to describe the clinical characteristics of patients with a biopsy indicating IgAN. Methods: This is a population-based cohort study. Out of 4,069 individuals with a renal biopsy consistent with IgAN (biopsies performed in 1974–2011), this study reviewed patient charts of a random subset of 127 individuals. Clinical and biopsy characteristics at the time of biopsy were evaluated, and positive predictive values (PPV) were calculated with 95% confidence intervals (CI). Results: Out of 127 individuals with a renal biopsy consistent with IgAN, 121 had a likely or confirmed clinical diagnosis of IgAN, primary or secondary to Henoch–Schönlein purpura, yielding a PPV of 95% (95% CI =92%–99%). The median age at biopsy was 39 years (range: 4–79 years); seven patients (6%) were <16 years. The male to female ratio was 2.8:1. The most common causes for consultation were macroscopic hematuria (n=37; 29%), screening (n=33; 26%), and purpura (n=14, 11%). In patients with available data, the median creatinine level was 104 µmol/L (range 26–986 µmol/L, n=110) and glomerular filtration rate 75 mL/min/1.73m² (range 5–173 mL/min/1.73m², n=114). Hypertension was noted in 59 (46%) individuals. IgA deposits were reported in 97% of the biopsy records (n=123), mesangial hypercellularity in 76% (n=96), C3 deposits in 89% (n=113), and C1q deposits in 12% (n=15). Conclusion: A histologic diagnosis of IgAN has a high PPV for a diagnosis of IgAN confirmed by review of patient charts. Keywords: general population-based, histopathology, IgA nephropathy, kidney, renal disease, validation studie

Asymmetries in punishment propensity may drive the civilizing process

Norms about hygiene and violence have both shown a tendency to become increasingly strict, in the sense that the handling of bodily fluids and the use of violence have become increasingly restricted. The generality of this directional change across a large number of societies has not been captured by previous explanations. We propose an explanation of the directional change that is based on the aggregation of everyday interactions. This theory posits that directional norm change can come about if there is an asymmetry in punishment propensity between the people who prefer stricter norms and those who prefer looser norms. Asymmetry in punishment can arise from underlying asymmetry in the threat perceived, where a stricter-than-preferred behaviour is perceived as inherently less threatening than a looser one. We demonstrate the logic of the theory using a formal model and test some of its assumptions through survey experiments.Knut and Alice Wallenberg Foundation grant 2016.0167 and 2015.0005; Professor Roy Weir Career Development Fellowship

Long-term suicide risk of depression in the Lundby cohort 1947–1997 – severity and gender

Objective: The long-term suicide risk of depression was evaluated in a community sample by severity and gender. Method: The Lundby study is a prospective, longitudinal cohort study on a population consisting of 3563 subjects. In 1947-1997 medium or severe depression according to the Lundby diagnostic system were registered in 503 subjects. The same subjects were also diagnosed according to DSM-IV showing major depressive disorder (MDD) in 293 and depressive disorder not otherwise specified (DDNOS) in 131 subjects. Results: The overall long-term suicide risk varied from 5.6% to 6.8%. The long-term suicide risk was 3.1% for medium and 11.4% for severe 'Lundby depression', 3.7% for medium and 13.8% for severe MDD + DDNOS, 3.1% for medium and 13.7% for severe MDD. Severity and male sex were risk factors for suicide. Conclusion: Males with a severe depression showed a high long-term risk for suicide, around 20%