Rhythmic entrainment of heart rate as a mechanism for musical emotion induction: A plausible hypothesis in need of evidence?

Several researchers have hypothesized that a musical rhythm can influence a listener’s heart rate through a process of entrainment and that this mechanism can influence the emotional feelings of the listener also. However, previous research has yielded mixed results, perhaps due to methodological problems. In this study, we independently manipulated the tempo of pieces of ambient instrumental music with a salient rhythm to influence the heart rate of 36 listeners with varying musical backgrounds, who also reported felt arousal and valence and subjective impressions of various induction mechanisms. Using a 2 × 2 × 2 factorial design, we manipulated direction (up vs. down) and magnitude (±3% vs. ±30%) of tempo change and extent of listener movement (finger tapping vs. still listening). For each trial, the tempo was manipulated in reference to the present heart rate of the individual listener. The results showed little evidence of entrainment. In general, listeners’ heart rate did not align with the target tempo (i.e., entrainment proper) nor did it change in the direction of the target tempo (i.e., entrainment tendencies). Instead, regardless of direction and size of tempo change, we observed a similar small increase in heart rate and arousal. The results are consistent with a general arousal effect of musical rhythm.