The present study conducted two experiments to examine the effects of syntactic priming in sentence comprehension, using a cross-modal priming task which required participants to make acceptability judgment of Japanese sentences with canonical and scrambled word orders. Experiment 1 investigated whether or not the speed of target sentence processing would be affected by the syntactic structure of prime sentences. Prime sentences matching target sentences in word order facilitated processing of target sentences even though prime-target pairs shared no content words, while prime-target pairs with mismatched word orders demonstrated weak facilitation effects. Experiment 2 examined the processing speed of target sentences primed by a sequence of nouns without any syntactic structure. The weak priming effects disappeared in the noun prime condition, which suggested that those observed in the mismatch condition in Experiment 1 were due to partial overlap of the syntactic structure. The overall results showed that the priming effects observed in these experiments were syntactic in nature and independent of lexical⁄semantic priming.
In order to learn novel actions, it is essential to observe and imitate similar actions performed by other individuals. Two experiments were conducted to investigate whether the participants bound together five meaningless postures during observation. The participants were divided into three groups according to the experimental conditions: the observation of postures, the imitation of postures, and the imitation of postures including the arm movements between subsequent postures, respectively. The participants' task was to memorize five sequentially-presented meaningless postures, after which the participants were either to recall the subsequent posture neighboring the one presented (Experiment 1), or to recognize and recall the same postures (Experiment 2). The participants were asked to discern the strategy judgments (visual or verbal encoding) they used for each trial. A number of joints functioning in the changes in the neighboring postures (1- and 4-step conditions) were manipulated. The results of Experiment 1 and 2 indicated that the correct recall rates (the binding effect) under the 1-step condition were higher than the 4-step condition in the imitation and the movement imitation groups, but that the binding effect was not to be found in the observation group. However, in both Experiment 1 and 2, binding effects were found in the correct recall rates in all three groups based on the visual encoding when the verbal encoding had been eliminated. The results suggest that observation elicits the binding between neighboring meaningless postures regardless of the imitation of body movement.
We investigated the effect of existing words on the generation of non-words. Native Japanese speaking college students (n = 103) generated 2702 non-words consisting of two to ten Hiragana letters during five minutes. The generated non-words resembled existing, familiar, Japanese words in terms of letter frequencies and of bigrams (two adjacent letters in a word). The non-words were also constrained by a phonological rule (*DD-constraint; Ito & Mester, 1996) of the Japanese lexicon, which implies that the non-words were related to existing words. and could be included in the extreme periphery of the Japanese lexicon. Further analysis indicated that the selection of letters in the generated non-words was biased. The participants tended to repeatedly use the same letters, and moreover, frequencies of letters in non-words were more redundant than those in existing words and random combination of letters. These results suggest that the generated non-words were influenced by existing words, but also constrained by characteristics of the process of retrieving letters from memory.