Wagley Neelima, Booth James R
Department of Psychology and Human Development, Vanderbilt University, Nashville, USA.
Department of Psychology and Human Development, Vanderbilt University, Nashville, USA.
Neuroimage. 2021 Nov 1;241:118416. doi: 10.1016/j.neuroimage.2021.118416. Epub 2021 Jul 21.
The present study examined the longitudinal relations of brain and behavior from ages 6-7.5 years old to test the bootstrapping account of language development. Prior work suggests that children's vocabulary development is foundational for acquiring grammar (e.g., semantic bootstrapping) and that children rely on the syntactic context of sentences to learn the meaning of new words (e.g., syntactic bootstrapping). Yet, little is known about the dynamics underlying semantic and syntactic development as children enter elementary school. In a series of preregistered and exploratory analyses, we tested how semantic and syntactic behavioral skills may influence the development of brain regions implicated in these processes, i.e. left posterior middle temporal gyrus (pMTG) and inferior frontal gyrus (pars opercularis, IFGop), respectively. Vice-a-versa, we tested how these brain regions may influence the development of children's semantic and syntactic behavioral skills. We assessed semantic (N = 26) and syntactic (N = 30) processes behaviorally and in the brain when children were ages 5.5-6.5 years old (Time 1) and again at 7-8 years old (Time 2). All brain-behavior analyses controlled for T1 autoregressive effects and phonological memory. Exploratory hierarchical regression analyses suggested bi-directional influences, but with greater support for syntactic bootstrapping. Across the analyses, there was a small to medium effect of change in variance in models where semantics predicted syntax. Conversely, there was medium to large change in variance in models where syntax predicted semantics. In line with prior literature, results suggest a close relationship between lexical and grammatical development in children ages 6-7.5 years old. However, there was more robust evidence for syntactic bootstrapping, suggesting that acquisition of phrase structure in school age children may allow for more effective learning of word meanings. This complements prior behavioral studies and suggests a potential shift in the early reliance on semantics to later reliance on syntax in development.
本研究考察了6至7.5岁儿童大脑与行为的纵向关系，以检验语言发展的自下而上理论。先前的研究表明，儿童的词汇发展是习得语法的基础（例如语义自下而上理论），并且儿童依靠句子的句法语境来学习新单词的含义（例如句法自下而上理论）。然而，对于儿童进入小学时语义和句法发展背后的动态过程，我们所知甚少。在一系列预先注册和探索性分析中，我们测试了语义和句法行为技能如何可能影响参与这些过程的脑区的发育，即分别为左后颞中回（pMTG）和额下回（岛盖部，IFGop）。反之，我们测试了这些脑区如何可能影响儿童语义和句法行为技能的发展。当儿童5.5至6.5岁时（时间1）以及7至8岁时（时间2），我们从行为和大脑两方面评估了语义（N = 26）和句法（N = 30）过程。所有脑-行为分析均控制了T1自回归效应和语音记忆。探索性层次回归分析表明存在双向影响，但对句法自下而上理论的支持更大。在各项分析中，语义预测句法的模型中方差变化有小到中等的效应。相反，句法预测语义的模型中方差有中等至较大的变化。与先前文献一致，结果表明6至7.5岁儿童的词汇和语法发展之间存在密切关系。然而，有更强有力的证据支持句法自下而上理论，这表明学龄儿童短语结构的习得可能使单词含义的学习更有效。这补充了先前的行为研究，并表明在发展过程中，早期对语义的依赖可能会向后期对句法的依赖发生潜在转变。
