Did your brain decide before you did? The science of free will

Free will is the idea that we can consciously and deliberately choose how we act.

It sounds obvious. Of course you decide what to eat, where to go, and what to say. 

But what if our idea of free will is not real? What if your brain has already started deciding before you become aware of it? This was discussed in a recent episode of Science Vs. titled ‘Free Will: Does It Exist?’.

The Case Against Free Will

The discussion started with the case against free will, with some of the most convincing evidence being Benjamin Libet’s experiment in the 1980’s:

Participants were asked to spontaneously flex their wrist. At the same time, they were asked to watch a clock and report at which moment they first became aware of their intention to move, whilst Libet recorded brain activity using EEG.

We might expect the order of events to go something like:

I decide -> my brain prepares the movement -> I move

But Libet found something surprising. Brain activity, that he called the ‘readiness potential’, appeared around 500 ms before participants became aware of their intention to move.

The sequence of events seemed more like:

My brain prepares the movement -> I become aware of my decision -> I move

Later research pushed this idea further. Using fMRI, Soon et al (2008) found patterns of brain activity as early as 10 seconds before participants were aware of deciding to push a button. Using machine learning techniques, these researchers were also able to make better-than-chance predictions about which decision a participant was going to make.

What this means: voluntary actions begin in the brain before we become conscious of them. Neuroscientists have interpreted this as an indication that there are predictable processes in the brain driving behaviour that we are unaware of (rather than managed by our free will).

Whilst this might seem like a knockout punch against free will, there are some caveats. Firstly, these experiments involve incredibly simple decisions - flicking your wrist is a long way from deciding whether to leave your job. Secondly, the predictive accuracy of these experiments were not perfect. Soon et al’s (2008) predictions were only 60% accurate - better than chance, but hardly perfect. Perhaps the readiness potential reflects a developing tendency towards the action, rather than a final decision, and maybe conscious thought can still influence what happens next. Free will may not be dead quite yet…

The Case in Favour of Free Will

Physicist Sean Carroll offered a compelling alternative viewpoint: emergence theory. 

Let’s think about the ocean. We know that the ocean exists. We know that there are tides, currents, and waves. But, if you were to look at an individual water molecule, you would not find any of these things. This is because the ocean only emerges when an enormous number of water molecules come together. It only exists at a different level of description.

Carroll suggests that something similar might be happening with free will. At the microscopic level, our brains consist of neurons, electrical signals, neurotransmitters, and molecular processes. Maybe the ‘you’ deciding is an emergent phenomenon that is derived from all of the processes occurring in your brain. 

So then, perhaps, free will is something that only emerges at this higher level. Your brain is not deciding instead of you, but rather it is influencing how you make the decision.

Convinced?

Emergence theory seems fairly convincing, and challenged my perspective on the topic, although there are still some important considerations to make. Whilst superficially it makes sense to think of free will like this, the idea of emergence is conceptually very vague, and it is unclear how emergent properties stem from these lower systems. It may also be that emergent properties reflect a fundamental limitation in human knowledge rather than new phenomena.

That being said, the episode concludes on a hopeful note: just because we are yet to figure out free will does not mean it is fake. Overall, this episode does a good job of presenting both sides of this longstanding debate and breaks down complex philosophical stances into digestible arguments in an entertaining way. I particularly enjoyed their explanation of emergence theory, which seriously challenged my belief that free will is a myth. 

What do you think? (Or is your brain doing the thinking for you?)

References

• Libet, B. (1985). Unconscious cerebral initiative and the role of conscious will in voluntary action. Behavioral and brain sciences, 8(4), 529-539.

• Soon, C. S., Brass, M., Heinze, H. J., & Haynes, J. D. (2008). Unconscious determinants of free decisions in the human brain. Nature neuroscience, 11(5), 543-545.

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This article was written by Lydia Roper and edited by Rebecca Pope, with graphics produced by Saba Keshan. If you enjoyed this article, be the first to be notified about new posts by signing up to become a WiNUK member (top right of this page)! Interested in writing for WiNUK yourself? Contact us through the blog page and the editors will be in touch.