Do we have free will? Researchers test mechanisms involved in decision-making

The brain-computer duel: Do we have free will?
A participant during the experiment. Credit: Copyright: Charité, Carsten Bogler

Our choices seem to be freer than previously thought. Using computer-based brain experiments, researchers from Charité - Universitätsmedizin Berlin studied the decision-making processes involved in voluntary movements. The question was: Is it possible for people to cancel a movement once the brain has started preparing it? The conclusion the researchers reached was: Yes, up to a certain point—the 'point of no return'. The results of this study have been published in the journal PNAS.

The background to this new set of experiments lies in the debate regarding conscious will and determinism in human decision-making, which has attracted researchers, psychologists, philosophers and the general public, and which has been ongoing since at least the 1980s. Back then, the American researcher Benjamin Libet studied the nature of cerebral processes of study participants during conscious decision-making. He demonstrated that conscious decisions were initiated by unconscious , and that a wave of brain activity referred to as a 'readiness potential' could be recorded even before the subject had made a conscious decision.

How can the unconscious brain processes possibly know in advance what decision a person is going to make at a time when they are not yet sure themselves? Until now, the existence of such preparatory brain processes has been regarded as evidence of 'determinism', according to which free will is nothing but an illusion, meaning our decisions are initiated by unconscious brain processes, and not by our 'conscious self'. In conjunction with Prof. Dr. Benjamin Blankertz and Matthias Schultze-Kraft from Technische Universität Berlin, a team of researchers from Charité's Bernstein Center for Computational Neuroscience, led by Prof. Dr. John-Dylan Haynes, has now taken a fresh look at this issue. Using state-of-the-art measurement techniques, the researchers tested whether people are able to stop planned movements once the readiness potential for a movement has been triggered.

"The aim of our research was to find out whether the presence of early brain waves means that further decision-making is automatic and not under conscious control, or whether the person can still cancel the decision, i.e. use a 'veto'," explains Prof. Haynes. As part of this study, researchers asked to enter into a 'duel' with a computer, and then monitored their brain waves throughout the duration of the game using electroencephalography (EEG). A specially-trained computer was then tasked with using these EEG data to predict when a subject would move, the aim being to out-maneuver the player. This was achieved by manipulating the game in favor of the computer as soon as brain wave measurements indicated that the player was about to move.

If subjects are able to evade being predicted based on their own brain processes this would be evidence that control over their actions can be retained for much longer than previously thought, which is exactly what the researchers were able to demonstrate. "A person's decisions are not at the mercy of unconscious and early . They are able to actively intervene in the decision-making process and interrupt a movement," says Prof. Haynes. "Previously people have used the preparatory brain signals to argue against free will. Our study now shows that the freedom is much less limited than previously thought. However, there is a 'point of no return' in the decision-making process, after which cancellation of movement is no longer possible." Further studies are planned in which the will investigate more complex decision-making processes.

Explore further

New brain research refutes results of earlier studies that cast doubts on free will

More information: Matthias Schultze-Kraft et al. The point of no return in vetoing self-initiated movements, Proceedings of the National Academy of Sciences (2015). DOI: 10.1073/pnas.1513569112
Citation: Do we have free will? Researchers test mechanisms involved in decision-making (2016, January 4) retrieved 19 September 2019 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Feedback to editors

User comments

Jan 04, 2016
Since the unqualified success of the program that corrupted the sanity of Ted Kazinski, one wonders if any research is being done to protect us from unethical social workers, psychlogical examiners and the like? One understands that the profession of psychiatry self-selects and so limits those with the inability to control injury to clients, but with the spread of the basics of psychology, even on tv, one comes into contact even at the level of marriage counselors and talk therapists.

Jan 04, 2016
Those researchers familiar with thiotimoline's intriguing bond structure are already aware of the experimental evidence for the interplay of free will and reality.

Jan 05, 2016
The implicit assumption is that consciousness is unitary, like a homunculus somewhere in the brain. If we make the opposite assumption, that conscious processes involve several regions of the brain, then it make sense that the result or even the process of conscious decisions are not known by every process involved in consciousness all the time.

That is, it takes some short period of time before every process involved in consciousness or even in the conscious decision making process can be aware of the result of a conscious decision.

Identifying some process that is not aware of some part of the decision making process can be interpreted as identification of at least two separate processes that contribute to consciousness or one can go with the homunculus interpretation and assume that the homunculus is not aware of decisions made by the brain...

Jan 09, 2016
@Vidyaguy - So true. (That was a good sci-fi story!)

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more