Many scientists once believed that physical similarities between identical twins are genetic, while their personalities, intelligence and other differences between them are an effect of their environment.
New findings now suggest that half of all differences in intelligence between people appear rooted in the collective influence of many tiny genetic variations.
最新研究调查显示，人与人之间智力的不同大半取决于基因上许多极小的差异。
3
These differences in structure and wiring do not appear to have any influence on intelligence as measured by IQ tests.