The perception of time is an important component of our human experience. It’s essential for day-to-day activities and any kind of complex behavior. However, the process underlying time is incompletely understood – including what role does the heart play. Now, researchers at Cornell University have found a possible answer.

Our momentary perception of time isn’t really continuous but instead stretches or shrinks with heartbeats, they argued, describing the heart as one of the brain’s important timekeepers. The idea of the heart playing a key role in our sense of timing actually goes back to ancient times, but has only been explored by a few studies.

“Time is a dimension of the universe and a core basis for our experience of self,” the study lead author Adam K. Anderson, a professor of Psychology at Cornell University, said in a media statement. “Our research shows that the moment-to-moment experience of time is synchronized with, and changes with, the length of a heartbeat.”

Time keeping

Time perception has so far been mostly studied over extended intervals, with researchers suggesting that thoughts and emotions often distort our sense of time – making it appear to run faster or slower. However, such findings tend to reflect on how we think about or estimate time, instead of our direct experience of it in the present.

To gain new insights into this, the researchers at Cornell University looked at whether our perception of time is related to physiological rhythms, such as the natural variability in heart rates. Although our heart ticks steadily most of the time, each interval between the beats is slightly longer or shorter than the previous one, they explained.

They set up an experiment with 45 participants aged 18 to 21 with no history of heart disease. They monitored them with electrocardiography (ECG), measuring their heart electrical activity at millisecond resolution. They then linked the ECG to a computer that produced audible tones lasting 80-180 millisecond resolution triggered by the participants’ heartbeats.

The researchers then asked the participants to report whether some tones were longer or shorter in relation to others. This unveiled a phenomenon they described as “temporal wrinkles.” When the heartbeat preceding a tone was shorter, the tone was then seen as longer. When the heartbeat was longer, the sound’s duration seemed shorter.

This shows that the “cardiac dynamics, even with a few heartbeats, is related to the temporal decision-making process,” the researchers wrote. The study also showed that the brain is influencing the heart. When participants focused on the sounds, this “orienting response” changed their heart rate, affecting their experience of time, they added.

“The heartbeat is a rhythm that our brain is using to give us our sense of time passing. And that is not linear – it is constantly contracting and expanding,” Anderson said in a statement. “Even at these moment-to-moment intervals, our sense of time is fluctuating. A pure influence of the heart, from beat to beat, helps create a sense of time.”

The study was published in the journal Psychophysiology.