Nobuyuki Jincho

Development of executive control and language processing

Research in executive function development has shown that children have poor control of inhibition functions, including the inhibition of prepotent responses, control of attention, and flexibility at rule-shifting. To date, links between the development of executive function and childrens language development have not been investigated explicitly. Yet, recent studies on childrens sentence processing report that children tend to perseverate during sentence processing. We argue that such perseveration may be due to immature executive function.

What Hinders Child Semantic Computation: Children's Universal Quantification and the Development of Cognitive Control.

Recent studies on the acquisition of semantics have argued that knowledge of the universal quantifier is adult-like throughout development. However, there are domains where children still exhibit non-adult-like universal quantification, and arguments for the early mastery of relevant semantic knowledge do not explain what causes such non-adult-like interpretations. The present study investigates Japanese four- and five-year-old childrens atypical universal quantification in light of the development of cognitive control. We hypothesized that childrens still-developing cognitive control contributes to their atypical universal quantification. Using a combined eye-tracking and interpretation task together with a non-linguistic measure of cognitive control, we revealed a link between the achievement of adult-like universal quantification and the development of flexible perspective-switch. We argue that the development of cognitive control is one of the factors that contribute to childrens processing of semantics.

Dissociating congruence effects in letters versus shapes : Kanji and kana

In order to consolidate the dissociation in feature integration found in earlier studies between letters of the Roman alphabet and corresponding pseudo-letters, the present study used kanji and kana and corresponding pseudo-letters, presented visually, either in isolation or surrounded by congruent or incongruent shape, as targets in a choice-response task with three different response criteria. When the criterion was shape, congruence effects were obtained for both real and pseudo-letters. With the second and third response criteria this result was found for pseudo-letters, but not for letters. These criteria either involved distinguishing between letters and visually similar pseudo-letters or distinguishing between visually similar letters. The dissociation of congruence effects between letters and pseudo-letters was therefore shown to depend on visual similarity between targets, independent of their category. This effect was found to be robust for kanji but not for kana, which is related to distinctions between these two writing systems.

Utterances in infant-directed speech are shorter, not slower

It has become a truism in the literature on infant-directed speech (IDS) that IDS is pronounced more slowly than adult-directed speech (ADS). Using recordings of 22 Japanese mothers speaking to their infant and to an adult, we show that although IDS has an overall lower mean speech rate than ADS, this is not the result of an across-the-board slowing in which every vowel is expanded equally. Instead, the speech rate difference is entirely due to the effects of phrase-final lengthening, which disproportionally affects IDS because of its shorter utterances. These results demonstrate that taking utterance-internal prosodic characteristics into account is crucial to studies of speech rate.

Individual Differences in Sentence Processing: Effects of Verbal Working Memory and Cumulative Linguistic Knowledge

The present study investigates individual differences in sentence processing. The Verbal Working Memory (VWM) model and the Two Factor Model, involving VWM and Cumulative Linguistic Knowledge (CLK), are compared in three self-paced reading experiments, in which ditransitive sentences containing high/low-frequency words (Exp. 1) and canonical/scrambled transitive verb sentences (Exp. 2, Exp. 3) are presented. Results favor the Two Factor model over the VWM model: the contributions of VWM and CLK to sentence processing are independent of each other. Two types of demands on VWM, temporal syntactic ambiguity and filler-gap dependency, are mediated by readers’ VWM capacity in scrambled sentences. CLK mediates lexical frequency effect and structural frequency effect on reading time and comprehension accuracy. We also find an interaction between VWM capacity and CLK in distant scrambling sentences, which suggests that CLK and VWM share the same cognitive resource.