Discussion

The aim of the present study was to investigate the influence of tonal relatedness on the ERPs correlates of pitch processing. In order to focus on cognitive expectations linked to listeners’ implicit knowledge of tonal regularities, tonal relatedness was manipulated by changing only one (possibly repeated) tone in the first part of the melodies. This resulted in most of the context tones and the target tones (both penultimate and final tones) being acoustically identical between related and less related conditions, thus controlling bottom-up expectations linked to contour, intervals or tone repetition. Also, to ensure that the ERPs elicited by tonal relatedness were not mixed with ERPs elicited by acoustic features (like consonance/dissonance), the tonal manipulation involved in-key tones only. Target tones were the tonic (the 1st scale degree) in the related condition and the subdominant (the 4th scale degree) in the less-related condition. This design ensured that ERPs elicited by the penultimate tones were not due to processing of acoustic incongruities, which has been pointed to be a concern in studies using stronger tonal violations (Koelsch et al., 2007; Poulin-Charronnat et al., 2006; Regnault et al., 2001). The “repeated-tone” design also ensures that ERPs elicited on the penultimate tones were not due to task-related decisional processes. In addition, ERPs associated to pitch discrimination were investigated on final tones, in interaction with tonal relatedness since final tones could be played either in-tune or out-of-tune besides being tonally related or less related.