1 Preparatory Remarks Locke asserts that " the Ideas of primary Qualities of Bodies, are Resemblances of them, and their Patterns do really exist in the Bodies themselves; But the Ideas, produced in us by these Secondary Qualities, have no resemblance of them at all. " 1 On an unsophisticated way of taking his words, he means that ideas of primary qualities are like the qualities they represent...

OBJECTIVE Resemblances between parents and children for alcohol use can be due both to cultural transmission and genetic inheritance. We examined the genetic and environmental determinants of the familial resemblances in alcohol use. METHOD With a parent-twin design a distinction was made between the contribution of genetic effects, the environmental influences shared by siblings and the effe...

Measures of four dimensions of personality (Psychoticism, Extraversion, Neuroticism, and Lie scores) and six aspects of social attitudes (to sex, taxation, militarism, politics, religion and a general conservatism scale) were obtained by mailed questionnaire from 29,691 US subjects including adult twins (n = 14,761) their parents (n = 2360), their spouses (n = 4391), siblings (n = 3184) and adu...

The heritability of the degree of residential area urbanization in twins and their siblings in the Dutch population was examined. The postal code was known for 6879 twins and 2724 siblings registered with the Netherlands Twin Register and born between 1940 and 1983. Using data from Statistics Netherlands, these postal codes could be related to residential area characteristics, including urbaniz...

A consistent finding from twin studies is that the environment shared by family members does not contribute to the variation in susceptibility to asthma. At the same time, it is known that environmental risk factors that are shared by family members are associated with the liability for asthma. We hypothesize that the absence of a main effect of shared environmental factors in twin studies can ...