Procedural finger-tapping task.

<p><b>A/B.</b> Subjects in the evening group showed a significantly greater improvement in finger-tapping speed across the first (<b>A</b>) and second (<b>B</b>) retention interval compared to the afternoon group<b>. C/D.</b> Subjects in the evening group showed a greater gain in accuracy (as indexed by a decrease in the error rate) across the first (<b>C</b>) and second retention interval (<b>D</b>)<b>.</b> Error bars depict SE, the asterisks (*) indicate statistical significance, <i>P</i><0.05.