The efficient interaction of indirect reciprocity and costly punishment

Human cooperation in social dilemmas challenges researchers from various disciplines. Here we combine advances in experimental economics and evolutionary biology that separately have shown that costly punishment and reputation formation, respectively, induce cooperation in social dilemmas. The mechanisms of punishment and reputation, however, substantially differ in their means for 'disciplining' non-cooperators. Direct punishment incurs salient costs for both the punisher and the punished, whereas reputation mechanisms discipline by withholding action, immediately saving costs for the 'punisher'. Consequently, costly punishment may become extinct in environments in which effective reputation building--for example, through indirect reciprocity--provides a cheaper and powerful way to sustain cooperation. Unexpectedly, as we show here, punishment is maintained when a combination with reputation building is available, however, at a low level. Costly punishment acts are markedly reduced although not simply substituted by appreciating reputation. Indeed, the remaining punishment acts are concentrated on free-riders, who are most severely punished in the combination. When given a choice, subjects even prefer a combination of reputation building with costly punishment. The interaction between punishment and reputation building boosts cooperative efficiency. Because punishment and reputation building are omnipresent interacting forces in human societies, costly punishing should appear less destructive without losing its deterring force.     

Detrimental effects of sanctions on human altruism

The existence of cooperation and social order among genetically unrelated individuals is a fundamental problem in the behavioural sciences. The prevailing approaches in biology and economics view cooperation exclusively as self-interested behaviour--unrelated individuals cooperate only if they face economic rewards or sanctions rendering cooperation a self-interested choice. Whether economic incentives are perceived as just or legitimate does not matter in these theories. Fairness-based altruism is, however, a powerful source of human cooperation. Here we show experimentally that the prevailing self-interest approach has serious shortcomings because it overlooks negative effects of sanctions on human altruism. Sanctions revealing selfish or greedy intentions destroy altruistic cooperation almost completely, whereas sanctions perceived as fair leave altruism intact. These findings challenge proximate and ultimate theories of human cooperation that neglect the distinction between fair and unfair sanctions, and they are probably relevant in all domains in which voluntary compliance matters--in relations between spouses, in the education of children, in business relations and organizations as well as in markets.     

Age-dependent changes in hippocampal synaptic transmission and plasticity in the PLB1Triple Alzheimer mouse

Several genetically engineered models exist that mimic aspects of the pathological and cognitive hallmarks of Alzheimer’s disease (AD). Here we report on a novel mouse model generated by targeted knock-in of transgenes containing mutated human amyloid precursor protein (APP) and microtubule-associated protein tau genes, inserted into the HPRT locus and controlled by the CaMKIIα regulatory element. These mice were crossed with an asymptomatic presenilin1_A246E overexpressing line to generate PLB1_Triple mice. Gene expression analysis and in situ hybridization confirmed stable, forebrain-specific, and gene-dose-dependent transgene expression. Brain tissue harvested from homozygous, heterozygous, and wild-type cohorts aged between 3 and 24 months was analyzed immunohistochemically and electrophysiologically. Homozygous PLB1_Triple offspring presented with mostly intracellular cortical and hippocampal human APP/amyloid, first detected reliably at 6 months. Human tau was already uncovered at 3 months (phospho-tau at 6 months) and labeling intensifying progressively with age. Gene-dose dependence was confirmed in age-matched heterozygous females that accumulated less tau and amyloid protein. General excitability of hippocampal neurones was not altered in slices from PLB1_Triple mice up to 12 months, but 2-year-old homozygous PLB1_Triple mice had smaller synaptically evoked postsynaptic potentials compared with wild types. Synaptic plasticity (paired-pulse depression/facilitation and long-term potentiation) of synaptic CA1 pyramidal cell responses was deficient from 6 months of age. Long-term depression was not affected at any age or in any genotype. Therefore, despite comparatively subtle gene expression and protein build-up, PLB1_Triple mice develop age-dependent progressive phenotypes, suggesting that aggressive protein accumulation is not necessary to reconstruct endophenotypes of AD.     

Last Night a Shrinkage Saved My Life: Economic Growth,Model Uncertainty and Correlated Regressors

We compare the predictive ability of Bayesian methods which deal simultaneously with model uncertainty and correlated regressors in the framework of cross‐country growth regressions. In particular, we assess methods with spike and slab priors combined with different prior specifications for the slope parameters in the slab. Our results indicate that moving away from Gaussian g‐priors towards Bayesian ridge, LASSO or elastic net specifications has clear advantages for prediction when dealing with datasets of (potentially highly) correlated regressors, a pervasive characteristic of the data used hitherto in the econometric literature. Copyright © 2015 John Wiley & Sons, Ltd.     

Contribution and Co-production: The Collaborative Culture of Linnaean Botany

This essay aims to elucidate the collaborative dimension of the knowledge-making process in eighteenth-century Linnaean botany. Due to its ever increasing and potentially infinite need for information, Linnaean botany had to rely more and more heavily on the accumulation and aggregation of contributions by many people. This, in turn, had a crucial impact on the genesis and form of botanical publications: the more comprehensive the project, the larger the effect. It was the botanist Carl Linnaeus who managed to establish himself as the centre of this contributory knowledge-making process. Given the exponential growth in the number of known species and the resulting need for observation, this was the necessary condition which allowed him continuously to update and correct his systematic works, and allowed them to maintain their status as the central catalogues of a global botany for decades.     

Studies of lipid extracts from red blood cells

Zusammenfassung 35 Sera von Patienten mit infektiöser Mononukleose (10 Kranke, 25 Rekonvaleszenten), 15 Sera von Patienten mit anderen Krankheiten und 15 normale Sera wurden im Komplementbindungstest geprüft, wobei als Antigen ein Lipoidextrakt von Rinder-Erythrozyten verwendet wurde. Sera von Rekonvaleszenten nach infektiöser Mononukleose zeigten eine spezifische Komplementbindung, während bei Patienten vor der Rekonvaleszenz die heterophilen Antikörper im Komplementbindungstest nur dann nachgewiesen werden konnten, wenn die Paul-Bunnellsche Reaktion auch positiv ausfiel.     

Cholesterol blood levels in Rh sensitized women treated with Rh hapten

Zusammenfassung Cholesterin lässt sich als Bestandteil des ungereinigten Rh-Haptens nachweisen. Deshalb wurde geprüft, ob die perorale Aufnahme dieser Fraktion den Blutcholesterinspiegel beeinflusst. Bei 17 Menschen, die kein Hapten erhielten, und bei 61 Hapten-Empfangenden wurde keine Erhöhung des Cholesterinspiegels festgestellt.