Why object clefts are easier to process than subject clefts in Japanese: Frequency or expectation?

摘要

文処理を扱った先行研究では傾度」と後続する構造に対する「予期」が重要な役割を果たしていると言われている。しかし，これらの要因のうちどちらの方がより強い影響力をもつかは明らかではない。本研究では，「頻度」と「予期」の影響について検討するために，日本語でコーパス分析を行い，主語分裂文と目的語分裂文の分布及び遷移的確率を調べた。結晃主語分裂文の頻度の方が目的語分裂文の頻度よりも高いのに対して，埋め込み動詞の位置における目的語分裂文の遷移的確率の方が主語分裂文よりも高いことがわかった。これらの結果を先行研究で観察された読み時間のデータと照らし合わせることで，日本語における分裂文処理の難しさを「予期」で捉えられるのに対して「頻度」では捉えられないことがわかった。%Previous studies have shown that both frequency and expectation for upcoming structures play an important role on sentence processing. However, it is still unclear which one of these factors has a stronger impact on sentence processing. In order to explore the possible effects of frequency and expectation; we conducted a corpus analysis in Japanese in the current study. We first calculated the distribution and transitional probabilities of subject and object clefts, and then compared them with reading time data in our previous study. The results showed the number of subject clefts was higher than object clefts, whereas transitional probability of object clefts was higher than subject clefts at the embedded verb position. The results indicate that expectation can account for the processing difficulty of clefts in Japanese, whereas the simple frequency failed to explain the processing difficulty.