The idea that some groups of people may be more intelligent than others is one of those hypotheses that dare not speak its name. But Gregory Cochran is (1)_____ to say it anyway. He is that (2)_____ bird, a scientist who works independently (3)_____ any institution. He helped popularize the idea that some diseases not (4)_____ thought to have a bacterial cause were actually infections, which aroused much controversy when it was first suggested.
(5)_____ he, however, might tremble at the (6)_____ of what he is about to do. Together with another two scientists, he is publishing a paper which not only (7)_____ that one group of humanity is more intelligent than the others, but explains the process that has brought this about. The group in (8)_____ are a particular people originated from central Europe. The process is natural selection.
This group generally do well in IQ test, (9)_____ 12-15 points above the (10)_____ value of 100, and have contributed (11)_____ to the intellectual and cultural life of the West, as the (12)_____ of their elites, including several world-renowned scientists, (13)_____. They also suffer more often than most people from a number of nasty genetic diseases, such as breast cancer. These facts, (14)_____, have previously been thought unrelated. The former has been (15)_____ to social effects, such as a strong tradition of (16)_____ education. The latter was seen as a (an) (17)_____ of genetic isolation. Dr. Cochran suggests that the intelligence and diseases are intimately (18)_____. His argument is that the unusual history of these people has (19)_____ them to unique evolutionary pressures that have resulted in this (20)_____ state of affairs.