Figure 1. Experimental conditions.

The first three tones are contextual eliciting a strong or weak prediction. The three contextual tones are presented at the same frequencies, albeit in different orders. The fourth tone can either be a high or low target frequency. The fourth tone can either consecutively follow the ascending or descending order (PredH and PredL), or the contextual tones could be deviant (MispredH and MispredL) or the contextual tones could be scrambled (UnpredH and UnpredL). The two predictable sequences were presented ten times per run, whereas the other four conditions were presented four times per run.