Yet DST, critical of genetic heritability, advocates developmentalist research of environmental effects, a logical inconsistency.[16] Barnes et al., made similar criticisms observing the innate human capacity for language (deeply genetic) does not determine the specific language spoken (an contextually environmental effect). It is then in principle possible to separate the effects of genes and environment.[17] Similarly, Steven Pinker argues if genes and environment couldn't actually be separated then speakers have a deterministic genetic disposition to learn a specific native language upon exposure. Though seemingly consistent with the idea of gene–environment interaction, Pinker argues it is nonetheless an absurd position since empirical evidence shows ancestry has no effect on language acquisition — environmental effects are often separable from genetic ones.[18]