Blind People Sense Their Heartbeats Better Than Sighted

Summary: Blind people are better than sighted people at sensing their own heartbeat, a new study reveals. The findings suggest those who are blind have a heightened ability to feel signals from inside their bodies than those who are not visually impaired.

Source: Karolinska Institute

Blind people are better at sensing their own heartbeats than sighted, shows a study by researchers at Karolinska Institutet in Sweden and Jagiellonian University in Poland. The study indicates that blindness leads to a heightened ability in feeling signals from the inner body.

The findings are published in the Journal of Experimental Psychology: General.

Thirty-six blind and as many sighted individuals were asked to count their own heartbeats without checking their pulse or touching their body. At the same time, the researchers recorded the participants’ actual heartbeats with a pulse oximeter. Then, they compared the reported with the recorded numbers to assess to what degree the participants were able to sense their own heartbeats.

The analysis showed that the blind participants were superior at sensing their heartbeats than sighted participants. The blind group had an average accuracy of 0.78 while the sighted group had an accuracy of 0.63 on average, according to a scale where 1.0 represented a perfect score.

“The blind participants were much better at counting their own heartbeats than the sighted participants in our study and in several previous studies,” says Dominika Radziun, PhD student at the Department of Neuroscience, Karolinska Institutet.

“It gives us important information about the brain’s plasticity and how the loss of one sense can enhance others, in this case the ability to feel what happens inside your own body.”

This shows a brain and a heart on a scale
The analysis showed that the blind participants were superior at sensing their heartbeats than sighted participants. Image is in the public domain

According to the researchers, this ability to sense heartbeats may provide an advantage when it comes to emotional processing. Prior studies have linked the degree of interoceptive accuracy, that is the ability to sense the internal state of the body, to how well people perceive emotions in themselves and others.

”We know that heart signals and emotions are closely interlinked; for example our hearts beat faster when we experience fear. It is possible that blind individuals’ enhanced sensitivity to signals from their own heart also impacts their emotional experiences,” says Dominika Radziun.

The research group will now continue to study how blind individuals perceive their own bodies, examining if structural changes in the visual cortex, the brain region normally responsible for vision, may explain the increased ability to sense signals from the inside of the body.

Funding: The study has been financed by the Swedish Research Council, the Göran Gustafsson Foundation, the Polish National Science Centre (Narodowe Centrum Nauki) and a Marie Skłodowska-Curie Intra-European Individual Fellowship.

About this neuroscience research news

Author: Press Office
Source: Karolinska Institute
Contact: Press Office – Karolinska Institute
Image: The image is in the public domain

Original Research: Open access.
Heartbeat counting accuracy is enhanced in blind individuals” by Dominika Radziun et al. Journal of Experimental Psychology: General


Heartbeat counting accuracy is enhanced in blind individuals

Blind individuals have superior abilities to perform perceptual tasks that rely on exteroceptive information, since visual deprivation is associated with heightened cross-modal plasticity.

However, it is unknown whether neuroplasticity after visual loss also affects interoception, that is, the sensations arising from one’s inner organs that convey information about the physiological state of the body.

Herein, we examine the influence of blindness on cardiac interoception, which is an interoceptive submodality that has important links to emotional processing and bodily self-awareness.

We tested 36 blind and 36 age- and sex-matched sighted volunteers and examined their cardiac interoceptive ability using the heartbeat counting task.

The results showed that blind individuals had significantly higher accuracy in perceiving their heartbeat than did individuals in a matched sighted control group.

In contrast, there were no significant differences between the groups in the metacognitive dimensions of cardiac interoception or the purely physiological measurement of heart rate, thereby underscoring that the improved accuracy likely reflects a superior perceptual sensitivity to cardiac interoceptive signals in blind individuals.

We conclude that visual deprivation leads to an enhanced ability to count one’s own heartbeats, which has important implications for the study of the extent of cross-modal plasticity after visual loss, understanding emotional processing in blind individuals, and learning how bodily self-awareness can develop and be sustained in the absence of visual experience.

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