Consanguinity and intelligence: does it matter for social peace?

"The most famous example of inbreeding is in ancient Egypt, where several Pharaonic dynasties collapsed after a couple of hundred years. In order to keep wealth and power within the family, the Pharaohs often married their own sister or half-sister and after a handful of generations the offspring were mentally and physically unfit to rule. Another historical example is the royal houses of Europe where royal families often married among each other because tradition did not allow them to marry people of non-royal class."


http://www.new1.dli.ernet.in/data1/upload/insa/INSA_1/20005bbc_407.pdf

http://europenews.dk/en/node/34368


http://adinakutnicki.com/2014/11/28/explosiveislams-mandated-barbarism-morphs-with-genetic-inbreedingcommentary-by-adina-kutnicki/

http://www.reproductive-health-journal.com/content/6/1/17/table/T1

http://link.springer.com/article/10.1007%2FBF01068128

"Indian Muslim school boys, ages 13 to 15 years, whose parents are first cousins, were compared with classmates whose parents are genetically unrelated on the Raven Standard Progressive Matrices, a nonverbal test of intelligence. The inbred group (N=86) scored significantly lower and had significantly greater variance than the non-inbred group (N=100), both on raw scores and on scores statistically adjusted to control for age and socioeconomic status. Genetic theory predicts both of these effects for a polygenic trait with positive directional dominance."

Another paper on intelligence and wealth which challenges the same consensus about social peace
http://www.sciencedirect.com/science/article/pii/S0160289614000981

Italy

Table 1.

Mean scores, standard errors and standard deviations and Greenwich IQs in student performance in the Italian regions in the PISA creative problem solving test (PISA-CPS 2012) and Greenwich IQs in student performance in the PISA 2006 tests of reading, mathematics and science (PISA-RMS 2006).

Italian regions	Mean score (SE)	SD	PISA-CPS 2012	PISA-RMS 2006
Northeast	527 (6.4)	91	101.56	101.25
Northwest	533 (8.6)	83	102.50	99.00
Center	514 (10.8)	93	99.53	—
South	474 (8.4)	82	93.28	91.00
South Islands	486 (8.5)	90	95.15	90.30