Empathic Effects Of Auditory Heartbeats

For millennia, the heart has been a metaphor of love and feeling. Perhaps this is because our heart often reflects our emotions. It slows when we are relaxed, and quickens when we are excited. One of the common threads of my research is studying how sound can carry emotional information. For my dissertation, I decided to research the empathic effects that hearing someone else’s heartbeat would have on listeners. Could it change our perception of other’s feelings? Could it increase our feelings of closeness to them? How would it affect our own hearts?

I studied the effects of auditory heartbeats on our transient empathic state and cardiac neurophysiology.

To answer these questions, I designed a controlled, counterbalanced neurophysiological study that analyzed the effects of auditory heartbeats on empathy. For the purpose of my study, I characterized empathy as i) the ability perceive the feelings of others (cognitive empathy) and ii) to be emotionally impacted by those feelings (affective empathy). I studied these effects relative to purely visual perception (visual-only) and their combination (audio-visual). I also studied two nested auditory factors: i) the effects of heartbeat tempo and ii) whether the tempo matched or mismatched the visual expression (congruency).

I varied the tempo of the auditory heartbeat, and studied its interaction with visual perception.

I compared responses to visual-only and audio-visual conditions and found that the auditory heartbeats i) changed listener’s perspective on the affective state of the other person (cognitive empathy) and ii) increased listener’s self-reported ability to “feel what [the imaginary person] was feeling” (affective empathy). Analysis of tempo revealed that faster heartbeats were associated with more changes in cognitive empathy and greater amounts of affective empathy, but only in the audio-only condition.

I was also curious of hearing the heartbeats of another person would impact listener’s hearts (i.e. their cardiac neurophysiology). I recorded their ECG and EEG while they completed each trial and then quantified differences in two measures of cardiac neurophysiology: i) Heartrate (HR) and ii) the Heartbeat Evoked Potential (HEP). I found a significant decrease in heartrate for the auditory heartbeat conditions that was absent in the visual-only conditions.

Heartrates decreased in response to the auditory heartbeats, implying a transient physiological relaxation.

I also analyzed the Heartbeat-Evoked Potential (HEP), a novel ERP that has been shown to modulate with interoceptive sensitivity & attention. After cleaning the EEG, identifying independent components (ICA) and performing cluster-based statistics, I found a frontal component of the HEP that was more negative during heartbeat listening compared to silence. Research on the HEP is still in development, but I interpreted this frontal negativity as evidence that interoceptive attention had decreased due to the auditory heartbeat of another person.

Centering EEG epochs around the R-peak and removing the cardiac artifact revealed a greater frontal negativity at 300-550ms. Participants were likely paying less attention to their own heartbeat.

Needless to say, there are many similarities between the heartbeat and the beat (“tactus”) of music. From these results, I theorized that a similar phenomenon underlies empathic listening to the beat of music. Furthermore, auditory heartbeats holds promise as an empathic technology, with both cognitive and affective components. I’d love to share my thesis here, but it is still unpublished. Contact me if you would like it sooner.