Writers, filmmakers, and playwrights have long known the power of a good story. Whether we’re laughing and crying with strangers in a theater, or debating theories of whodunit in the psychological thriller you’re both reading, stories have always brought humans together.
When we think about how stories connect us, we tend to think about shared emotional experiences—the feelings the stories elicit in us. A study published Tuesday in Cell Reports suggests that stories connect us in an unconscious way as well: They can synchronize our heart rates. The researchers’ findings have implications for education, disorders of consciousness like coma, and a better understanding of the mind-body connection.
Lucas C. Parra, a professor of Biomedical Engineering at City College of New York and one of the researchers on the study tells Inverse, “[Research has shown] significant similarities in how the brain responds to a narrative... there were also hints that the timing of the heart is affected when you get something surprising happening. So we thought let’s put the two together and see if there are similarities across people.”
What they did— The researchers conducted four different experiments to analyze the relationship between attention to “narrative stimuli” and heart rate. In every experiment, the participants’ heart rates were monitored with an electrocardiogram. Additionally, because breath can affect heart rate, in all the experiments, the breathing rates of the volunteers were monitored.
In the first experiment, volunteers listened to an audiobook of 20,000 Leagues Under the Sea.
In the second experiment, volunteers watched short, instructional videos. In other words, videos without any emotive content whatsoever.
In the third experiment, volunteers listened to short children’s stories. Some participants were listening while distracted, others were paying full attention to the stories.
Finally, the fourth experiment included both people healthy volunteers and patients with “disorders of consciousness,” like being in a coma or vegetative state. All the participants listened to the audiobook of a children’s story. Here, the researchers wanted to determine whether people with conditions affecting consciousness had similar heart rates to those in the healthy group and if that was correlated with their health outcomes.
What they found — In the first experiment, the researchers found that the participants’ heart rates fluctuated as they followed the story of 20,000 Leagues Under the Sea. That’s not unexpected, Parra says, as healthy hearts have fluctuating heart rates. What’s notable is that the listeners’ heart rates fluctuated in a similar way at the same parts of the story.
You might be tempted to think volunteers’ heart rates were responding to the emotional ups and downs in the story. Which is precisely what the second experiment sought to determine.
In the second experiment, the first time the participants watched the non-emotive, instructional videos, their heart rates showed similar fluctuations. They then watched the videos again, this time counting backward in their head, which decreased how much attention they could pay to the video. When they did, the synchronicity of their participants’ heart rates decreased significantly, indicating that attention to the story was vital to synchronicity.
When the participants listened to the children’s stories in the third experiment, the group that could correctly answer questions about the stories (volunteers who were paying attention) had more similar heart rate fluctuations to one another than the distracted group.
In the fourth experiment, the people with disorders of consciousness had lower rates of heart synchronization than did the control group. When they were assessed six months later, the patients who had shown closer synchronization with healthy controls had regained some consciousness — in other words, they had better outcomes.
Digging into the details — In every case, the researchers found that the participants who were paying attention to the story had increased synchronicity in their heart rates with one another.
Further, breath rates weren’t correlated with heart rate, suggesting that the cognitive processing of the story was responsible for the heart rate fluctuations.
Why it matters — This study suggests an easy way to measure attention and consciousness, Parra says.
There may also be implications for assessing patients with disorders of consciousness. While more research needs to be done to confirm the researchers’ initial findings if it’s confirmed that patients with the closest heart rate fluctuations to healthy controls are the most likely to regain at least some consciousness, that could dramatically change how hospitals assess the prognosis of patients with disorders of consciousness.
Tapping into the rhythms of heartbeat and harnessing them through stories could ultimately create a virtuous cycle — boosting consciousness, alertness, and attention.
What’s next — Parra sees a future in which researchers use this finding to build tools to understand what helps students pay attention to instructional videos or online schooling.
If they accomplish that, Parra says, “we might be able to guide interventions. If you’re zoning out on Zoom, a) can we detect it? and b) can we correct it?”
“There’s a growing interest in how the brain serves to maintain the body. People are noticing that their mental state affects their health and vice versa,” Parra says. “This study is a step forward in understanding the brain-body connection.”
Summary: Heart rate has natural fluctuations that are typically ascribed to autonomic function. Recent evidence suggests that conscious processing can affect the timing of the heartbeat. We hypothesized that heart rate is modulated by conscious processing and therefore dependent on attentional focus. To test this, we leverage the observation that neural processes synchronize between subjects by presenting an identical narrative stimulus. As predicted, we find significant inter-subject correlation of heart rate (ISC-HR) when subjects are presented with an auditory or audiovisual narrative. Consistent with our hypothesis, we find that ISC-HR is reduced when subjects are distracted from the narrative, and higher ISC-HR predicts better recall of the narrative. Finally, patients with disorders of consciousness have lower ISC-HR, as compared to healthy individuals. We conclude that heart rate fluctuations are partially driven by conscious processing, depend on attentional state, and may represent a simple metric to assess conscious state in unresponsive patients.