AI Summary
5 min readFree Will: Does It Exist?
In the 1980s, neurophysiologist Benjamin Libet put electrodes on people's scalps and asked them to flex their wrists whenever they felt the urge. He found a brain signal appearing before people said they consciously decided to move. The gap was about half a second. Decades later, neuroscientist John-Dylan Haynes used fMRI to replicate the finding—and found a signal appearing seven seconds before people reported making a decision between pressing a left or right button. Seven seconds is a long time to be wrong about when you decided something. But does that mean free will is an illusion? The answer, it turns out, is more complicated than the viral internet videos suggest.
The Classic Challenge: Your Brain Decides Before You Do
The core experimental setup is deceptively simple. Volunteers sit in a scanner and spontaneously choose to press either a left or right button whenever they feel like it. Meanwhile, the scanner records brain activity, and participants note the exact moment they consciously decide. Haynes and his team used machine learning algorithms to see whether they could predict which button someone would press before the person knew they'd decided. The prediction was about 60% accurate—modestly above chance. Other groups using different techniques pushed that accuracy above 80%.
Continue reading the full summary in the app — free to try.
Read Full Summary →Free • No credit card required
Never miss an episode of Science Vs
Get every new episode summarized in your inbox — free, ~5 minutes to read.
No spam. Unsubscribe anytime.
What you'll learn
- 1 (00:11) **The Free Will Debate Is Everywhere** - Social media videos celebrate doing whatever you want, while other corners of the internet argue free will is an illusion.
- 2 (03:25) **Introducing the Expert and the Stakes** - Meryl Horn (PhD) joins to explore the science behind free will, starting with the real-world consequences of believing it's an illusion.
- 3 (05:21) **Defining Free Will** - The episode establishes a clear, scientific definition of free will to ground the debate.
- 4 (08:22) **The Classic Experiment: Benjamin Libet (1980s)** - A landmark neurophysiology experiment attempts to see if brain activity precedes conscious decision-making.
- 5 (12:11) **The Modern Replication: John-Dylan Haynes (2008)** - A more advanced fMRI study replicates and extends Libet's findings, showing brain activity a full seven seconds before a conscious decision.
- 6 (17:38) **Interpreting the Brain Signals** - The host and Meryl debate what the "blip" means, questioning whether it disproves free will or just shows that consciousness is a latecomer to the decision process.
- 7 (21:15) **The Case for Free Will: Emergence** - Physicist Sean Carroll introduces the concept of "emergence" to argue that free will can be real even if the brain follows physical laws.
+ Full timestamped outline available in the app
Show Notes
Will you hit play on this episode?? It feels like that decision is totally within your control — but what if it’s not? What if free will is just an illusion? Lots of people are using science to say that free will is a trick of the mind, that whether or not you listen to this episode, or eat a taco, or do a silly dance right now — it’s all predestined. But do we really have science receipts for that? We find out by talking to neuroscientist Prof. John-Dylan Haynes and theoretical physicist Prof. Sean Carroll.
Find our transcript here: https://tinyurl.com/ScienceVsFreeWill
Check out Sean Carroll’s podcast, Mindscape, here: https://preposterousuniverse.com/podcast/
In this episode, we cover:
(00:00) When you remember you have free will
(02:21) What is free will?
(04:26) The argument against free will(18:07) The argument for free will
This episode was produced by Meryl Horn with help from Rose Rimler, Ekedi Fausther-Keeys, Michelle Dang and Wendy Zukerman. We’re edited by Blythe Terrell. Wendy Zukerman is the executive producer. Fact checking by Erica Akiko Howard. Mix and video editing by Bobby Lord. Music written by Bobby Lord, Bumi Hidaka, So Wylie, Emma Munger and Peter Leonard. Thanks to the researchers we spoke to for this episode, including Dr. Nicolas Rouleau and Dr. Andrea Lavazza. And special thanks to Chris Suter and Humdinger Studios.
Science Vs is a Spotify Studios Original. You can join us for free on Spotify or wherever you get your podcasts. Follow us and tap the bell for episode notifications.
Learn more about your ad choices. Visit podcastchoices.com/adchoices
More from this podcast
Science Vs →