First, it races away unstoppably—then it seems to stand still. Our perception of time is anything but constant. Two new studies suggest our heartbeat can cause passing moments to drag or fly.
The experiments, led by separate research groups, have uncovered complementary findings. Together, their work confirms that the heart’s activity influences our perception of time as it passes. “It shows that you can’t look at [the experience of time] in isolation from the body,” says cognitive neuroscientist Irena Arslanova of Royal Holloway, University of London, who is lead author of one of the studies.
In April Arslanova and her colleagues reported in Current Biology that time perception changes with each heartbeat. In their initial experiment, 28 people learned to distinguish the duration of two visual or two auditory stimuli. For example, the study participants looked at two shapes or heard two distinct tones. One item or sound from each pair was presented for 200 milliseconds (ms), and the other was presented for 400 ms.
Next, people saw a new cue—another tone or shape—and had to estimate whether the presentation felt shorter or longer, using the previous pair for reference. But there was an added twist. These new sounds and visuals were matched to a particular moment in the rhythm of someone’s heart rate: when the heart either contracted (the systole) or relaxed (the diastole) during the heartbeat.
During systole, the volunteers perceived time duration to be shorter than it actually was. During diastole, the exact opposite was true. The researchers suspect that the overestimation and underestimation typically cancel each other out. “One way to think about it is: Our eyes blink and open, but our visual perception is stable…. It’s only when one dominates the other that a distortion will come about,” Arslanova says.
According to Arslanova and her colleagues, the phenomenon may be explained by the fact that pressure sensors in blood vessel walls send signals to the brain. As a result, between heartbeats, the sensor activity drops, giving the brain more capacity to process incoming information. This increase in sensory impressions could make time feel longer.
In a second experiment, the group repeated its procedure and this time presented 39 people with photographs of emotionally expressive faces. The researchers again found that the heart’s activity distorted the experience of time at the scale of milliseconds—and that a state of heightened arousal, piqued by emotional images, seemed to make time pass faster.
In parallel, a group at Cornell University published a similar finding in the journal Psychophysiology in March. The researchers focused on variability in time perception between single heartbeats. When that span is longer, they discovered, time feels slower. When there is less time between two beats, the perception of time seems to move even faster. The team called these tiny time distortions “temporal wrinkles.”
Researchers from both groups caution that this work is not necessarily telling us about the way we perceive specific events—such as time flying when we’re having fun or dragging when we’re bored. Those experiences are influenced by many factors, including our emotion and attention. They also happen at a totally different scale from the milliseconds-long temporal wrinkles.
Instead, as cognitive neuroscientist Adam K. Anderson of Cornell explains, the new work illuminates how the heart influences the experience of time as it unfolds. “Time is made up of those milliseconds,” he says. “These little moments probably tell a larger story.”
Anderson, who was one of the authors of the March study, adds that how the body and brain relate is of growing interest in neuroscience. “People are comfortable with the idea that the brain can influence what the heart does,” he says. But reversing that relationship is novel. “That your brain might be listening to patterns in your heart to shape something as fundamental as the passage of time… we find that really interesting.”
This article originally appeared in Spektrum der Wissenschaft and was reproduced with permission.