Word production requires conceptual preparation, lexical processes, phonological processes, and motor preparation. Indefrey and Levelt (2004) proposed the time course of these stages in serial progress, without including the effect of overt speech. To clarify this effect, we recorded electroencephalogram from participants performing the following three tasks: naming, phonology, and category tasks. We found that task differences were observed sequentially as the model suggested. Moreover, a semantic interference effect was observed only in naming task. Our results suggest that the speech motor command of the word affects early lexical-semantic processes. We propose some modifications of the model include cascade and interaction between stages.

「この運動は我々が起こしている」と感じる感覚を共同運動主体感という．本研究では，共同作業中の2者の脳波を同時計測し，共同運動主体感と2者の脳波同期の関係から共同運動主体感の生起に関わる脳領域を調査した．実験の結果，相互に協調し合う共同作業課題において，リーダーの右前頭葉とフォロワーの右側頭頭頂接合部（rTPJ）のθ波の活動同期が高まり，共同運動主体感も脳波同期とともに高まることが示された．