Neuroscience's Say On Free Will

It has been debated for the past half-decade wether creatures possess "Free-will" or if everything is predetermined by out of reach forces. Considering free will is fundamental for personal independence and responsibility for one's actions, it is a sensitive topic of which is still merely debated and no significant proof has been found to reject or prove free will.


The brain, giving one the ability to think, reason, plan, and make decisions. Generally, such capabilities link to philosophical questions at some point, such as "Free-will". The question, in short, searched for the answer on whether all our actions come from free will or if it's all predetermined.

In 1984, the neurophysiologist Benjamin Libet examined an EEG chart. It is believed that a person's actions turn physical once an elevation in neural activity is generated in the premotor cortex, also called "Readiness potential". Assuming the same potential reflects the responding of neurons in the premotor cortex, which in turn stimulates the motor neurons through feedforward projections. Following the spikes in the graph, it makes on wonder whether the process from the premotor cortex to motorneurons firing occurs before any conscious awareness of an individual. In that case, we are only conscious once the action is performed and thus justify subconsciously for our actions in the belief of them coming from free will!

In 1964, Two German scientists, Hans Helmut Kornhuber and his doctoral student Lüder Deecke investigate the brain's ability in generating spontaneous actions. They recorded participants' brain activity and then reversed the patterns, which got the name “reverse-averaging,” and proved the existence of Readiness potential, meaning an intention involved and thus the existence of a free will.


Libet also performed a separate experiment, where he gathered a controlled group of people to sit in front of a clock and told to catch the time once they get the urge to move their arm. The action of moving an arm is performed by brain activity patterns with one of the important regions for movement being the premotor cortex, located rostrally to the motor cortex.


The description of the patterns; At first there is the intention period with a gradual increase in firing rate of neurons in the premotor cortex and once the movement begins the neurons return to baseline level to promote motor intention (readiness potential). Once EEG electrodes are placed above the premotor cortex, the firing activity is higher when an individual attends to the urge to move (red line) and lower when an individual attends to the movement (blue line). The conscious intention to act was proven from 300ms. Further investigations have shown that our brains predict our actions as much as 20 seconds in advance. In this case, consciousness is an effect, passive observer, and not a cause to our actions.


Libet argued for free will by suggesting the capability to override decisions made in advance, which indicates that there is in fact power in conscious awareness and thus free will. In this case, actions predicted by the brain are rejected or permitted which proves that behaviors are unpredictable to some extend.


A later experiment asked individuals to chose which of two pictures were attractive when all the pictures had been rated nearly equal by a controlled group. Then, without the participants noticing, the experimenter switched the pictures and asked for a justification for the participant's rating. Considering the majority did not notice the switch, they were then found to make up explanations instead. This indicates that the human brain often makes up reasons and tinkers with the memories in order to support what it thinks occurred. This in contrast to Lebit's belief in overriding decisions, suggests that free will is only a fabricated phenomenon by humans to make sense of a determined reality we can’t explain, nor accept.


“Neuroscientists who study human patients have shown that if you stimulate a part of the motor area to generate a certain behavior, the person will come up with a story about why they had volition to do that action. I don't know if we have free will or not, but I think that as you start to see more and more examples like that of situations where clearly their free will did not generate their action, but their brain nevertheless, for consistency, makes up a reason that it did.” - James Fitzgerald



Reference

  1. https://www.theatlantic.com/health/archive/2019/09/free-will-bereitschaftspotential/597736/

  2. https://www.frontiersin.org/articles/10.3389/fpsyg.2019.00326/full

  3. https://www.frontiersin.org/articles/10.3389/fpsyg.2019.00326/full

Graphs/charts: Neuroscience sixth edition by Dale Purves.

Cover Image Credit: https://en.wikipedia.org/wiki/Benjamin_Libet

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