Have you ever gone ahead and eaten that piece of chocolate, despite yourself?
Do you inadvertently make decisions because you are hungry or cold? In other words, does the brain's processing of internal bodily signals interfere with your ability to act freely?
This line of thinking is at the heart of research that questions our ability to act on thoughts of free will. We already know that inner body signals, like the heartbeat, affect our mental states, can be used to reduce the perception of pain and are of fundamental importance for bodily self-consciousness.
Thanks to a new discovery, it turns out that these inner body signals do indeed affect acts of volition.
Scientists at EPFL in Switzerland have shown that you are more likely to initiate a voluntary decision as you exhale. Published in today's issue of Nature Communications , these findings propose a new angle on an almost 60-year-old neuroscientific debate about free will and the involvement of the human brain.
We show that voluntary action is indeed linked to your body's inner state, especially with breathing and expiration but not with some other bodily signals, such as the heartbeat." Olaf Blanke, EPFL's Foundation Bertarelli Chair in Cognitive Neuroprosthetics and senior author
At the center of these results is the readiness potential (RP), a signal of brain activity observed in the human cortex that appears not only before voluntary muscle movement, but also before one becomes aware of the intention to move. The RP is the signature of voluntary action since it consistently appears in brain activity measurements right before acts of free will (like being aware that one wants to reach for the chocolate).
Interpretations of the RP have been debated for decades. Some interpret the RP to show that free will is an illusion, since the RP precedes the conscious experience of free will. It seems to show that the brain commits to a decision (chocolate) before we are even consciously aware of having made that decision. [See box The readiness potential and interpretations.]
More recently, it was suggested that the RP could be an artefact of measurement, potentially putting free will back into our command.
But if we take on the view that our conscious decisions arise from a cascade of firing neurons, then the origin of the RP may actually provide insight into the mechanisms that lead to voluntary action and free will. The way the brain's neurons work together to come to a decision is still poorly understood. [See hidden patterns of brain activity unveiled by higher dimensional algebraic topology.] Our conscious experience of free will, our ability to make decisions freely, may then be intricately wired to the rest of our body.
The EPFL results suggest that the origin of the RP is linked to breathing, providing a new perspective on experiences of free will: the regular cycle of breathing is part of the mechanism that leads to conscious decision-making and acts of free will. Moreover, we are more likely to initiate voluntary movements as we exhale. (Did you reach for that piece of chocolate during an exhale?)
These findings suggest that the breathing pattern may be used to predict 'when' people begin voluntary action. Your breathing patterns could also be used to predict consumer behavior, like when you click on that button. Medical devices that use brain-computer interfaces could be tuned and improved according to breathing. The breathing-action coupling could be used in research and diagnostic tools for patients with deficits in voluntary action control, like obsessive compulsive disorders, Parkinson disease, and Tourette syndromes. Blanke and Hyeong-Dong Park, first author of this research, have filed a patent based on these findings. Free will hijacked by interoceptive signals?
More generally, the EPFL findings suggest that acts of free will are affected by signals from other systems of the body. Succumbing to that urge to eat chocolate may depend more on your body's internal signals than you may realize!
Blanke elaborates, "That voluntary action, an internally or self-generated action, is coupled with an interoceptive signal, breathing, may be just one example of how acts of free will are hostage to a host of inner body states and the brain's processing of these internal signals. Interestingly, such signals have also been shown to be of relevance for self-consciousness."
You may be tempted to blame acts of chocolate binging on interoceptive electrical signals hijacking your free will. The gut-mind connection is an active field of research and interoceptive messages sent to the brain certainly impact food cravings. For now, this latest EPFL research only improves predictions of when you will indulge in that craving, and not what you actually crave. Acts of free will and inner states of the body Related Stories
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