Is cousin marriage bad for offspring health?

The most interesting articles that came to our attention this week

Predicting harm among incels (involuntary celibates): the roles of mental health, ideological belief and social networking (accessible). Joe Whittaker and colleagues examine the demographic make-up and social attitudes of incels in the US and UK. They find most incels are heterosexual childless men in their mid twenties. They also find that incels have very poor mental health and are more likely to identify as left-of-centre.

Germs in the Family: The Short-and Long-Term Consequences of Intra Household Disease Spread. Meltem Daysal and colleagues examine the long-term consequences of getting hospitalised for respiratory infection as a child. They find that younger siblings have 2–3 times higher hospitalisation rates, most likely because older siblings bring home infections. This helps to explain why older siblings earn more than younger siblings.

“General Intelligence,” Objectively Determined and Measured. In a classic article from 1904, Charles Spearman introduces the concept of general intelligence. Analysing data on students’ grades in various subjects, he finds that they are all positively correlated. He posits the existence of a general factor of intelligence that influences performance in diverse subjects, as well as specific factors that influence performance in particular subjects.