Experiment 1 sequence design.

<p>Participants each heard four sequences consisting of two feature-present sequences and two feature-absent sequences. Stem-down high notes are 1000 Hz and stem-up low notes are 500 Hz. Rare runs are targets to be detected in the longer sequence of common runs. Green borders are around common runs; orange borders are around rare runs. Dashed lines are around flat runs; solid lines are around change runs.