Underpinning the On-Line Processing of (Non-)Canonical Sentences in German-Speaking Four-Year-Olds: The Interplay of Cognitive Control and Memory Capacity

This study investigates the interpretation of object-initial sentences in German-speaking children. We addressed the following questions: (1) Which morphosyntactic cues do children deploy to process object-initial sentences? (2) Which executive function (EF) abilities support them during this task? This study examined the effect of case and number agreement morphology in 4;6-year-old German-speaking children (N = 27) on their interpretation of unambiguous S(ubject)-V(erb)-O(bject) and OVS sentences by combining an offline (sentence-picture matching) and an online (looking-while-listening) paradigm. Participants' working memory and cognitive control abilities were assessed by means of a (forward) digit-span test and a flanker task. Case-marked OVS sentences were processed more accurately than number-marked ones, although both conditions were less accurate than SVO sentences. We found a comprehension facilitation driven by higher cognitive control skills that enhances, specifically the interpretation of the more demanding number cue in OVS structures already in 4;6-year-olds. Higher working memory skills are generally associated with children's processing skills as they support the correct parsing of all online conditions and of both SVO and OVS in the offline case condition. We conclude that while case-marking appears to be processed more reliably than number by preschoolers, also number information alone can be processed, especially by children with higher cognitive control skills.