单项选择题

In her 1998 book, The Nurture Assumption, Harris argued that when it comes to children’s success, parents don’t matter at all: the diversity in children’s outcomes that we see is pretty much entirely accounted for by genes and peer influences, except, perhaps, in cases of extreme abuse.
In the Wall Street Journal, science writer Jonah Lehrer made a similar case, but only regarding rich parents, not poor ones--at least in terms of early child intelligence.
For her book, Harris reviewed massive amounts of data on parenting styles, and found that much of it was filled with methodological flaws. In her review, there was little research to suggest that parenting made any huge difference in child personality. She noted that societal swings in parenting practices--from strict to permissive and back again--didn’t seem to change much the fundamental mix of personalities or intelligence that we see. But it’s not clear whether these findings are really due to a lack of effect, or an inability to measure it and clarify all the variables.
Now, based on a new twin study that followed 750 identical and fraternal twins(异卵双胞胎)from age 10 months to 2 years, Lehrer argues that the influence of poor parents matters, but that of rich ones does not. The study found that 80% of the difference in kids’ intelligence by age 2 was attributable to home environment--but only among poor kids.
That idea, however, misses a few big things. For one, as Lehrer notes, the study did find that at age 10 months, parents were the biggest influence on children’s intelligence across all socioeconomic classes. Since later development builds on earlier experience, it’s not as though the first 10 months don’t count.
Secondly, choices about things like child care can matter tremendously. Although this is an extreme example, Dr. Bruce Perry, in his book Born For Love: Why Empathy Is Essential and Endangered, tells the story of a wealthy child who was parented by multiple sequential nannies. When the child seemed to become more attached to a nanny than to his mother--which was inevitable because the nanny spent the most time with the child in this familyIthat nanny was fired. The family went through 18 different nannies, subjecting the child over and over to the stress of abandonment, and the boy grew up to be a sex offender. Dr. Perry has also seen other cases of severe consequences of this kind of disrupted care-giving in wealthy children.
Harris was correct to point out the flaws in the evidence that show that parenting is the main determinant of a child’s future. And Lehrer is right that if the childhood environment were made equally good for all, the only variance in intelligence we’d see would be down to genes.

What is the finding of a new study Jonah Lehrer used（）

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