Concurrent activation of high- and low-level production processes in written composition.

Writing a text requires the coordination of multiple high-level composition processes in working memory, including planning, language generation, and reviewing, in addition to low-level motor transcription. Here, interference in reaction time (RT) for detecting auditory probes was used to measure the attentional demands of (1) copying in longhand a prepared text (transcription), (2) composing a text and pausing handwriting for longer than 250 msec (composition), and (3) composing and currently handwriting (transcription + composition). Greater interference in the transcription + composition condition than in the transcription condition implies that high-level processes are activated concurrently with motor execution, resulting in higher attentional demands. This difference was observed for adults who wrote in standard cursive, but not for children and not for adults who used an unpracticed uppercase script. Greater interference in the composition condition than in the transcription condition implies that high-level processes demand more attention than do motor processes. This difference was observed only when adults wrote with a practiced script. With motor execution being relatively automatic, adults were able to attend fully to the high-level processes required in mature, effective composition. One reason that children fail to engage in such high-level processes is that motor processes deplete available attention.