Brain Signals Show Up Seven Seconds Early, but the Original Author Says Free Will Is Still Here
Libet's and Haynes's experiments show brain signals arriving half a second to seven seconds before ‘you decide’, but the original authors deny this means free will is dead; compatibilism holds that the will may be a macroscopic emergence from microscopic brain processes, the way temperature emerges from atoms.
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If choice is an illusion, the ‘I’ is not the decider
A genre of video circulates on social platforms: people say ‘I just remembered I have free will’ and then do something arbitrary — dumping all the cutlery into a drawer unsorted, climbing into the attic and eating chips like a goat. The routine celebrates freedom, but another corner of the internet says everything was determined long ago. The host points out that scientists have been publishing papers arguing free will does not exist for decades, and the question is no joke: if choice is an illusion, is the ‘I’ still the one making the decision?
— Wendy ZuckermanRead one line saying free will is an illusion and people cheat more
Merrill cites a body of psychology experiments: subjects are given something to read claiming science has proven free will is an illusion, and then their behavior is observed. The results show people cheat more, help others less, and are more likely to behave aggressively. Wendy's reaction is immediate: if I listen to the end and conclude I have no free will, I can say ‘I had no choice’ and offload everything. Merrill corrects that it may not necessarily come to that, but the answer on free will does affect people's sense of responsibility and moral behavior.
— Merrill HornHumans are trains stuck on tracks, unable to escape physical law
The usual definition of free will is: between chocolate and caramel, it is ‘I’ who decides, and it is not a random dice roll. But classical physics paints a clockwork universe: a ball rolls downhill because of gravity, every event determined by prior causes; the human body is likewise a collection of molecules whose next move could in theory be predicted from physics and biology. John Dylan Haynes of Charité in Berlin uses the image of railway tracks: a person is like a train stuck on rails, unable to escape the path laid down by natural law.
— Merrill HornThe brain decides seven seconds early; consciousness is just a passenger
In the 1980s Benjamin Libet's experiments had already found that about half a second before subjects reported ‘deciding to move’, a small signal appeared in the scalp EEG. John replicated and pushed this further with fMRI: 14 subjects freely chose to press a left or right button, and brain signals appeared a full 7 seconds before people reported making the decision. Wendy counts out 7 seconds live to demonstrate how long that is — your brain may have already prepared the decision, and consciousness is only a passenger catching up.
— Merrill HornSixty percent accuracy cannot carry ‘the decision was already made’
John used machine learning to analyze brain signals and see whether he could predict left or right before subjects were aware of it; accuracy came out around 60% — above the 50% of a coin flip, but far from perfect. Merrill is not impressed by 60%; another group using a different technique pushed prediction to 80% just before the decision. These studies became the ammunition of the debate: John's paper has been cited by other papers nearly 3,000 times. But for opponents, the core message is: the brain is already leaning toward a choice before you know it.
— Merrill HornTemperature is not in a single atom, and choices are just as real
Theoretical physicist Sean Carroll offers a compatibilist framework: weather forecasting depends on temperature, pressure, and humidity, but you cannot see temperature on a single atom — only when a large number of atoms gather do these quantities appear, and this is called emergence; waves in the ocean likewise exist only at the macroscopic level, yet no one doubts the ocean is real. By analogy, he says, the ‘you’ who makes decisions is a macroscopic emergence from all the microscopic processes of the brain; the fact that every neuron below obeys physical law does not mean the experience of choosing above is an illusion.
— Merrill Horn / Sean CarrollPressing a button cannot tell you whether to have a child
Merrill aims at the soft spot of the opposition: the lab tasks are just pressing a button or flicking a wrist, far removed from ‘should I have a child’ or ‘should I marry this person’. Using the most basic motor decisions to infer life's major choices is itself an untested assumption. Even granting that brain signals precede consciousness does not mean free will has been falsified — it only shows that the process of deciding is more complex than we thought.
— Merrill HornNeurons fire first, and it is still ‘you’ deciding
John Dylan Haynes, who ran the 7-second experiment, clarifies personally: in the 2008 paper he deliberately did not write ‘there is no free will’, because he wanted to publish the findings first and set the philosophical controversy aside. He himself leans toward thinking that even if neurons fire before the decision, it is still ‘you’ deciding — the definition of the ‘self’ needs to include unconscious processes too. The episode's landing point is therefore not ‘free will has been defeated’ but ‘free will needs to be reunderstood’.
— John Dylan HaynesIn their own words · checked verbatim
in these videos, you'll see people saying, I just remember, I have free will.
Wendy Zuckerman0:00
And these studies find that people will act worse.They're more likely to cheat less likely.
Merrill Horn5:00
Like you can't look at one little atom and see that it's 20 degrees outside.
Merrill Horn23:11
We were quite careful, So, by the way.Not to say in that 2008 paper that there's no free will.
John Dylan Haynes30:00
Figures
| Time by which the readiness potential preceded the subjective decision in Libet's experiment | about half a second | 9:41 |
| Time by which brain signals preceded the reported decision in Haynes's fMRI experiment | 7 seconds | 14:05 |
| Machine-learning prediction accuracy for left/right button presses (John's experiment) | about 60% | 16:25 |
| Prediction accuracy in another group's experiment | over 80% | 17:36 |
| Times Haynes's 2008 paper has been cited by other papers | nearly 3,000 | 17:36 |
| Number of subjects in the fMRI experiment | 14 | 14:05 |
| Number of references cited in this episode | 22 | 31:15 |
Glossary
- Emergence
- A new property that appears when a large number of microscopic parts form a whole, as temperature does from atoms.
- Clockwork universe
- The classical physics picture: everything is like a wound-up clock, and every event is determined by prior states.
- fMRI
- An imaging technique that measures where brain activity occurs; Haynes used it to record signals before a decision.
- EEG
- Electrodes on the scalp measure electrical activity; Libet used it to discover the readiness potential.
How to listen
Founders wrestling with whether their choices are really theirs, product leads who need to define where decision responsibility lies, and tech readers who have been fed fatalism by algorithmic feeds but have never heard the compatibilist case.
The sponsor reads in the front and back segments can be fast-forwarded; the core content is concentrated in 0:00-31:15.