Familial handedness and access to words, meaning, and syntax during sentence comprehension

We compared right-handed familial dextral (FS^-) and familial sinistral (FS⁺) participants who were aged either 10-13 years (children) or 18-23 years (adults). In word probe and associative probe tasks, FS⁺ adults responded faster than all other groups and FS⁺ children responded more slowly than all other groups. In the word probe task, only the FS^- adults showed a significant effect of the serial position of the target word. We interpret these differences to support an analysis-by-synthesis model of comprehension in which individuals who differ in familial handedness and age emphasize different linguistic representations during comprehension. In general, FS⁺ individuals focus on words and meaning, while FS^- individuals focus on syntactic representations. In FS⁺ individuals, age-related experiences with language produce a shift in responding from compositional meaning to words and their associations. In FS^- individuals, age-related experiences with language produce a shift toward responding based more on detailed syntactic representations, including the serial order of words and possibly the structural roles of clauses.