Motor templates in typing

This study investigated performance of typists transcribing texts presented visually. Keystrokes were analyzed as a function of (a) the fingers used for typing digrams, (b) frequency of digrams in language, (c) word context in which trigrams were embedded, and (d) duration of typing sequence for the word. Biomechanical and linguistic factors influenced interstroke intervals. However, over and above these factors, it was demonstrated that words are typed with sequences of movements whose temporal structure depends on the word and on the typist. The set of ratios between interstroke intervals remained unchanged within the range of rhythms observed in transcription. A counting mechanism was postulated to explain this finding. Four variations of the mechanism were compared on the basis of the pattern of temporal variability.