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Our Brains Make Up Our Minds Before We Know It

Brain activity can foretell some choices before subjects are conscious of them.

We like to think that when it comes to our daily decisions, we’re the ones running the show. For example, when you opt for the Matcha Green Tea Latte instead of your usual Cinnamon Dulce Latte, you’d like to believe that you made the conscious decision to switch. But what if that purchase intention was already made before you became aware of your decision to buy it?

Philosophers have argued about the concept of free will for thousands of years. In recent decades, neuroscientists have joined in on the debate. Some argue that our awareness of decisions may merely be a neurochemical afterthought, without any influence at all on one’s actions. These cognitive scientists cite brain imaging studies revealing that the decision-making process begins before a person is able to realize it.

Startling evidence to support belief in the role of the unconscious in decision-making was demonstrated in an experiment by a group of scientists led by John-Dylan Haynes from the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany. Using fMRI brain scans, these researchers were able to predict participants’ decisions as many as seven seconds before the subjects had consciously made the decisions. As the researchers concluded in Nature Neuroscience, “Many processes in the brain occur automatically and without involvement of our consciousness. This prevents our mind from being overloaded by simple routine tasks. But when it comes to decisions, we tend to assume they are made by our conscious mind. This is questioned by our current findings.”

The decision studied was a simple choice of whether or not to push a button with one’s left or right hand. Participants were free to make the decision whenever they wanted, but they had to indicate at what point they made the decision in their mind. By observing micropatterns of brain activity, the researchers were able to predict the subjects’ choices before they indicated knowing the choices themselves. “Your decisions are strongly prepared by the brain activity. By the time consciousness kicks in, most of the work has already been done,” says Haynes. This unprecedented prediction of a free decision raises profound questions about the nature of free will and conscious choice.

But because this study involved a very simple and less reasoned choice, Haynes and his team decided to explore whether or not these observations would generalize to more complex and considered choices. In a follow-up study, researchers presented a series of numbers on a screen and asked subjects to make a decision to either add or subtract two numbers. While participants were in the process of deciding, the researchers used fMRI brain imaging to decode and predict responses based on brain activity. The researchers argued that this task was a more realistic model of everyday decision-making as it involved more abstract intentions.

Similar to the earlier experiment, the researchers were able to predict the subjects’ choices based on brain activity up to four seconds before research participants were consciously aware of their choices. As published in Proceedings of the National Academy of Sciences, the report concludes, “Our results suggest that unconscious preparation of free choices is not restricted to motor preparation. Instead, decisions at multiple scales of abstraction evolve from the dynamics of preceding brain activity.”

Haynes is quick to point out, “Of course a single experiment is not going to rewrite two and half thousand years of thinking about free will. I like to think of this as a starting block.” But by better understanding our volitions, experiments such as these may provide important practical applications. For example, the research may have implications for informing consumers to make better choices or informing legal systems and juries to better deliberate about involuntary and voluntary acts. In addition, it may shed light on illnesses like schizophrenia and Parkinson’s disease, where patients feel as if their actions are not the result of their choosing.


Chun Siong Soon, Marcel Brass, Hans-Jochen Heinze & John-Dylan Haynes, (2008). Unconscious determinants of free decisions in the human brain, Nature Neuroscience, April 13.

Chun Siong Soon, Anna Hanxi He, Stefan Bode, John-Dylan Haynes, (2013). Decoding abstract intentions, Proceedings of the National Academy of Sciences, March.

John-Dylan Haynes, (2013) WORLD.MINDS: Do We Have Free Will? (Charité Berlin).

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