Figure 2. Example of experimental stimuli and experimental procedure.

The left panel of (A) illustrates the chord functions. The chord built on the first scale tone is denoted as the tonic (T), the chord on the second scale tone as the supertonic (st), on the fourth scale tone as subdominant (S), and on the fifth scale tone as the dominant (D). The major chord on the second tone of a scale can be interpreted as the dominant to the dominant, or double dominant (DD). The right panel of (A) illustrates examples of the polyphonic sequences in C major (duration of each sequence was 3 s). Chord sequences ended either on a tonic chord (T, regular), or on a double dominant (DD, irregular). Figure 2(A) was obtained from ref 14. Arrows indicate pitches that were not contained in the preceding chords. The lower panel (B) illustrates the experimental procedure: It consisted of pre-test, practice, EEG experiment, and post-test. During the EEG experiment (but not during pre- or post-test), participants were either informed (by a green or a red fixation cross, cued condition), or not informed (by a white fixation cross, non-cued condition) about whether the sequence would end on the regular (tonic) or the irregular (DD) chord, so that participants could learn to predict regular and irregular endings in the cued condition.