Dividing attention without alternation or automaticity.

Spelke, Hirst, and Neisser trained two subjects to copy unrelated words at dictation as they read and understood stories. The subjects ' success was interpreted as evidence against the hypothesis of a fixed attentional capacity or limited cognitive resources; instead, it was hypothesized, attention is a skill that improves with practice. However, other explanations of these results can be proposed. The present research addressed two such counterhypotheses: that capacity may be alternated between reading and writing and that the writing task may become "automatic," and require no capacity at all. Experiment 1 was designed to see whether subjects take intermittent advantage of the redundancy of the stories to switch to the writing task. Some subjects were trained to copy words while reading highly redundant material (short stories); others were trained with less redundant encyclopedia articles. On reaching criterion, each subject was switched to the other type of reading material. Three of the four subjects trained with stories transferred their skill immediately to the encyclopedia, suggesting that they had not been using the redundancy of the stories to accomplish