OVERLAPPING MENTAL OPERATIONS IN SERIAL PERFORMANCE WITH PREVIEW - TYPING - A REPLY

Pashler (this issue) concluded that the rate of responding in serial c hoice reaction tasks was controlled by a limit on simultaneous respons e selection rather than on simultaneous response execution. Film of a skilled typist shows that each finger movement starts as a key earlier in the sequence to be typed is struck (three earlier with words, two with orthographically legal non-words). Thus, her rate of responding i s controlled by a limit on the number of responses that can be execute d simultaneously, not by a limit on response selection. Preventing sim ultaneous response selection is one possible strategy for maintaining correct response order in serial tasks. It is suitable for tasks such as those studied by Pashler, where response selection is relatively sl ow and response execution is quick. Other strategies are more suitable for tasks where response selection is quick and response execution re latively slow and variable.