ABSTRACT

Non-shared environmental variance (NSEV) accounts for 76% of variance in genetic modelling of handedness. However, it is very misleading to suggest that NSEV, “highlights the importance of non-genetic factors for the ontogenesis of hemispheric asymmetries”. NSEV is poorly named, is calculated only by subtraction, and provides no direct evidence for environmental effects in the sense of the external environment. Miller suggested that it would be better named as “residual effect”. Mitchell has suggested that much or indeed most of NSEV is “developmental variance” and should be included under the heading of nature rather than nurture, and in handedness, “largely reflect[s] the outcome of randomness in brain development”. Overall only a very small proportion of NSEV in handedness is likely to be related to external environmental factors in the usual sense of the term.

摘要

非共享环境方差 (NSEV) 占惯用手遗传建模方差的 76%。然而，认为 NSEV“强调了非遗传因素对半球不对称个体发生的重要性”是非常具有误导性的。NSEV 命名不佳，仅通过减法计算，并没有提供外部环境意义上的环境影响的直接证据。米勒建议将其命名为“剩余效应”会更好。米切尔建议，大部分或实际上大部分 NSEV 是“发育差异”，应该包括在自然而不是后天的标题下，而在惯用手中，“很大程度上反映了大脑发育随机性的结果”。