Evolutionary precursors of social norms in chimpanzees: a new approach

Moral behaviour, based on social norms, is commonly regarded as a hallmark of humans. Hitherto, humans are perceived to be the only species possessing social norms and to engage in moral behaviour. There is anecdotal evidence suggesting their presence in chimpanzees, but systematic studies are lacking. Here, we examine the evolution of human social norms and their underlying psychological mechanisms. For this, we distinguish between conventions, cultural social norms and universal social norms. We aim at exploring whether chimpanzees possess evolutionary precursors of universal social norms seen in humans. Chimpanzees exhibit important preconditions for their presence and enforcement: tolerant societies, well-developed social-cognitive skills and empathetic competence. Here, we develop a theoretical framework for recognizing different functional levels of social norms and distinguish them from mere statistical behavioural regularities. Quasi social norms are found where animals behave functionally moral without having moral emotions. In proto social norms, moral emotions might be present but cannot be collectivized due to the absence of a uniquely human psychological trait, i.e. shared intentionality. Human social norms, whether they are universal or cultural, involve moral emotions and are collectivized. We will discuss behaviours in chimpanzees that represent potential evolutionary precursors of human universal social norms, with special focus on social interactions involving infants. We argue that chimpanzee infants occupy a special status within their communities and propose that tolerance towards them might represent a proto social norm. Finally, we discuss possible ways to test this theoretical framework

Placental vascular defects in compromised pregnancies: effects of assisted reproductive technologies and other maternal stressors

Many factors negatively affect pregnancy establishment and subsequent fetal growth and development, including maternal factors such as nutritional stress, age, body mass index, and genetic background, and external factors including environmental stress, psychosocial stress, multiple fetuses, medical conditions (e.g., polycystic ovary syndrome), lifestyle choices (e.g., alcohol consumption, smoking), and assisted reproductive technologies. These same factors have similar consequences for placental growth and development, including vascular development. We and others have shown that placental vascular development begins very early in pregnancy and determines, to a large extent, placental function—that is, the magnitude of the increase in placental blood flow and thus nutrient transport to the fetus. During the peri-implantation period and also later in pregnancy, cloned (somatic cell nuclear transfer) embryos exhibit a variety of placental defects including reduced vascularization and altered expression of angiogenic factors. Although placental defects are less pronounced in pregnancies resulting from the transfer of in vitro fertilized embryos, we and others have recently demonstrated that vascularization, expression of angiogenic factors, sex steroid receptors, several epigenetic markers, and growth of utero-placental tissues all were altered during early pregnancy after transfer of embryos obtained through natural mating, in vitro fertilization, or other assisted reproductive techniques. These observations are in agreement with the recent reports that in humans even singleton pregnancies established with assisted reproductive techniques are at increased risk of preterm delivery and low birth weight, and seem especially relevant considering the rapidly expanding use of these techniques in humans and animals