The problem of serial order in skilled typing.

We address the problem of serial order in skilled typing, asking whether typists represent the identity and order of the keystrokes they type jointly by linking successive keystrokes into a chained sequence, or separately by associating keystrokes with position codes. In 4 experiments, typists prepared to type a prime word and were probed to type a target word. We varied the overlap between the identity and order of keystrokes in the prime and the target. Experiment 1 tested whether the identity of keystrokes can be primed separately from their order. Experiments 2 and 3 tested whether keystroke positions can be primed out of sequence. Experiment 4 tested whether keystrokes are primed equally across serial positions. The results were consistent with chaining theories: Keystroke identities were not primed separately from their order, keystroke positions were not primed out of sequence, and priming was graded across the keystroke sequence and depended on the number of keystrokes that were primed in sequence. We conclude by discussing the possibility that the problem of serial order may be solved differently for different sequential tasks.