There is continuing debate about what explains cooperation and self-sacrifice in nature and in particular in humans. This paper suggests a new way to think about this famous problem. I argue that, for an evolutionary biologist as well as a quantitative social scientist, the triangle of two...

As the number of young children in daycare increases, people start to worry about the effect of early non-parental care. This is of special relevance as investments in the early periods of life are shown to be most important for a child’s long term development. Based on the German national...