单项选择题

To study something scientifically, you first have to measure it, and psychologists have developed tests for many mental traits. And contrary to popular opinion, the tests work pretty well. They give a similar measurement of a person every time they are administered, and they statistically predict life outcomes like school and job performance, psychiatric diagnoses, and marital stability. Tests for intelligence might ask people to recite a string of digits backward, define a word like " predicament, " identify what an egg and a seed have in common, or assemble four triangles into a square. Personality tests ask people to agree or disagree with statements like " Often I cross the street in order not to meet someone I know, " "I often was in trouble in school, " "Before I do something I try to consider how my friends will react to it, " and " People say insulting and vulgar things about me. " People"s answers to a large set of these questions tend to vary in five major ways; openness to experience, conscientiousness, extroversion, agreeableness(as opposed to antagonism), and neuroticism. The scores can then be compared with those of relatives who vary in relatedness and family background. The most prominent finding of behavioral genetics has been summarized by the psychologist Eric Turkheimer: "The nature-nurture debate is over... All human behavioral traits are heritable. " By this he meant that a substantial fraction of the variation among individuals within a culture can be linked to variation in their genes. Whether you measure intelligence or personality, religiosity or political orientation, television watching or cigarette smoking, the outcome is the same. Behavioral geneticists like Turkheimer are quick to add that many of the differences among people cannot be attributed to their genes. First among these are the effects of culture, which cannot be measured by these studies because all the participants come from the same culture, typically middle-class European or American. The importance of culture is obvious from the study of history and anthropology. The reason most of us don"t challenge each other to duals or worship our ancestors or chug down a nice warm glass of cow urine has nothing to do with genes and everything to do with the milieu in which we grew up. But this still leaves the question of why people in the same culture differ from one another. According to the findings reported in this article, what of the following is NOT statistically predictable