Cooperative child care among humans, where individuals other than the biological mother (allomothers) provide care, may increase a mother’s fertility and the survivorship of her children. Although the potential benefits to the mother are clear, the motivations for allomothers to provide care are less clear. Here, we evaluate the kin selection allomothering hypothesis using observations on Hadza hunter-gatherers collected in ten camps over 17 months. Our results indicate that related allomothers spend the largest percentage of time holding children. The higher (...) the degree of relatedness among kin, the more time they spend holding, supporting the hypothesis of nepotism as the strongest motivation for providing allomaternal care. Unrelated helpers of all ages also provide a substantial amount of investment, which may be motivated by learning to mother, reciprocity, or coercion. (shrink)

In this study, 191 subjects, 93 male and 98 female undergraduate business students, were asked to respond to a 51 item questionnaire to examine their perception of what constituted a "just society". The subjects agreed on 16 characteristics which a just society would have. Out of 51 there were only 10 statements whereon average responses showed significant differences based on gender.

In a recent issue of this journal Berit Brogaard and Kristian Marlow claim that an absolute frame of reference is compatible with Einstein’s Special Relativity. To achieve this they tweak Einstein’s famous train and embankment thought experiment and unjustifiably attribute, to Einstein, Hans Reichenbach’s claim that cause and effect are always temporally separated. Their conclusion is incompatible with the proper Lorentz transformations to show how time dilates from one frame of reference to another; transformations they show no evidence of (...) having done. I refute their conclusion by doing the calculations. (shrink)