How should we decide who, or what, is conscious?

Summary

Short Wave Podcast Summary

Episode Title: How should we decide who, or what, is conscious?
Date: July 13, 2026
Hosts: Regina Barber, Rachel Carlson

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Overview

This episode of Short Wave dives into the nature of consciousness: how scientists define it, how medical technologies are beginning to measure it, and what those discoveries might mean for people, animals, and potentially even artificial intelligences. The episode explores both groundbreaking neurological research and the deep ethical dilemmas introduced by new ways of detecting consciousness, especially in people unable to communicate. Throughout, creativity and humor make the discussion accessible to all listeners.

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Key Discussion Points and Insights

1. The Challenge of Defining Consciousness

• No Simple Answer: The episode starts by acknowledging the complexity and fuzziness of the word "consciousness."
  • Neuroscientists and philosophers describe it variously as “the experience we’re having right now” (05:34), or “what it is like to eat chocolate or look at the blue sky” (05:38).
  • Neuroscientist Anil Seth states: “Without consciousness, there really isn't anything at all. I mean, life matters to us because we're capable of having experiences.” (06:07)

2. Real-Life Case Study: Adrian Owen and the Tennis Test

• Background: Adrian Owen, neuroscientist at the University of Western Ontario, worked with patients in vegetative states who appeared completely unresponsive.
• The Tennis Test: Owen asked a patient to imagine playing tennis while her brain was scanned with an fMRI.
  • Healthy brains show movement-related activity during this test.
  • Remarkably, the vegetative woman’s brain activity was “indistinguishable from a completely walking, talking, healthy person.” (03:09)
  • Later studies revealed 20-25% of vegetative patients showed similar responses, upending previous beliefs about consciousness in such conditions. (03:19, 03:35)

3. Innovative Technologies for Detecting Consciousness

• The 'Imagination Test': Tasks like asking patients to imagine physical activity to elicit specific brain activity patterns are gaining traction in research. (07:35, 07:39)
• The Brain 'Echo' or TMS Test: Another technique disturbs the brain with a magnetic pulse (TMS) and measures the resulting activity.
  • Neuroscientist Marcello Massimini likens a conscious brain's reaction to “an orchestra that is well trained…with different instruments and different partitions.” (08:49)
  • In unconscious or vegetative brains, these regions do not ‘play together,’ resulting in a simpler, localized response. (09:15)
• Expert Impressions: Liad Mudryk highlights that no one test is sufficient by itself; a combination gives a more complete picture. (10:09)
• Caveats: Most tests are years away from widespread medical use due to their complexity and cost. (10:29, 10:35)

4. Ethics and Societal Implications

• Moral Weight: Detecting consciousness has major ethical implications, influencing decisions around end-of-life care, medical treatment, and even questions about animal rights and AI personhood.
• Ethical Quandaries:
  • "Being able to detect consciousness has wide implications... Think about being able to detect consciousness in fetuses... That's a huge question that has a lot of implications." — Liad Mudryk (11:10)
  • Philosopher Tim Bain notes: “You're better off doing your best to provide those assumptions with as solid a theoretical, scientific basis as you can.” (12:17)
• History Reminder: Cautions are raised about tests like IQ scores, which have a record of misuse, stressing the need for careful, ethical deployment of any new consciousness measure. (10:54)

5. The Broader Impact: AI, Animals, and Human Uniqueness

• Application Beyond Medicine: Once we have reliable ways to test for consciousness in people, this technology could chart new paths in understanding animal consciousness or developments in AI and robotics. (11:41)
• Human Identity: The episode frames consciousness as "an emerging tension point" as humanity explores what truly sets us apart — or possibly doesn’t — from artificial intelligences.

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Notable Quotes and Memorable Moments

• Defining Consciousness:
  “I think the best way to define consciousness is the way you might go about defining jazz… you play some jazz.” — Tim Bain (05:48)

• The Reality of Vegetative Patients:
  “Her brain activity was indistinguishable from a completely walking, talking, healthy person.” — Gina (03:09)

• Measuring Brain Reactions:
  “It's a little bit like banging on the brain with an electrical hammer, and you listen to the echo.” — Anil Seth (08:26)

• Limitations and Ethics:
  “Every question we ask about consciousness is loaded with ethical implications.” — Liad Mudryk (11:10)

• Practical Caution:
  “You're better off doing your best to provide those assumptions with as solid a theoretical, scientific basis as you can.” — Tim Bain (12:17)

• Anecdote:
  Some patients who recovered later said they remembered everything that happened when they were presumed unaware: "That's definitely not true for everyone, but I do think it points to how important consciousness is when it comes to these very real decisions about someone's quality of life." — Rachel Carlson (13:24)

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Timestamps for Key Segments

• 00:44: Introduction to the theme: measuring consciousness, especially in medical and AI contexts
• 01:50: Story of Adrian Owen and the groundbreaking "tennis test"
• 03:35: Discovery that 20-25% of vegetative patients respond to consciousness tests
• 05:28: Philosophers and neuroscientists discuss the challenge of defining consciousness
• 07:35: Overview of brain imaging and imagination tests (tennis example)
• 08:00 - 09:15: Introduction and explanation of the TMS ‘brain echo’ test
• 10:09: Expert caution: Combining tests gives the most accurate picture
• 10:54: Raising ethical and social implications of consciousness testing
• 11:10: Ethical dilemmas: implications for fetuses, animals, and AI
• 12:17: Tim Bain on the necessity of a scientific basis for assumptions about consciousness
• 13:24: Human stories: patients recovering and recalling experiences
• 13:41: Looking ahead: the future of consciousness research and technology

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Conclusion

This episode highlights the scientific, philosophical, and ethical complexity surrounding consciousness. Advances like the tennis test and brain echo technique are reshaping notions of awareness in patients once thought unresponsive. But the power to measure consciousness also poses profound ethical dilemmas — about medicine, the treatment of animals, and the rights of AI — all pointing to consciousness as a defining (and still mysterious) boundary for human identity and care.

For More: You can hear more science deep-dives from the Short Wave team every Monday as part of their Tech Camp summer series.

Transcript

[NPR Announcer]

This message comes from ixl, a learning platform for helping students maintain summer academic progress. A single subscription covers math, science, and reading for all children in a household. Receive 20% [e-mail] NPR. You're listening to Shortwave from NPR.

[Regina Barber]

Hey, Shortwavers. Regina Barber here with our next installment of Shortwave's summer series, Tech Camp. Every Monday, check this feed for a new episode about the technological frontier, tracking down the breakthroughs, experiments, and innovations that could change everything. And today, producer Rachel Carlson is here to talk about consciousness. Hey, Rachel.

[Rachel Carlson]

Hi, Gina. So a lot of people have been thinking about this, especially in the context of AI, like, is that AI models sentient? Do they have their own experience of the world? But it's a really tricky question to answer just for humans. So that's where we're going to start with a neuroscientist named Adrian Owen. He's a professor at the University of Western Ontario, and he's also the chief scientific officer at kraios, which sells a system to assess brain health. Back in the early 2000s, Adrian met a woman who'd been hit by two cars and suffered severe brain injury as a result. She was in what doctors call a vegetative state. And right now, the big test doctors use if someone's in this kind of state to see if they're conscious or not involves asking them to look at objects or respond to sounds or move their hands. But this woman couldn't do those things. Her eyes were open, but she couldn't respond to doctors to tell them if she was aware of what was happening or in pain.

[Gina]

Wow.

[Regina Barber]

Okay. So was she conscious?

[Rachel Carlson]

No one was sure. But Adrian wasn't content just not knowing. So he decided to see if he could find out if she was aware of anything going on around her. To do that, he put her in a brain scanner and asked her to imagine playing a game of tennis. So if you or I do this exercise, Gina, it probably sounds something similar to what Adrian thinks about.

[Gina]

I'm on my own. I'm say at Wimbledon. I'm facing my opponent at the other end of the. At the court, and I'm waiting for a fast serve, and here it comes swinging my arm, hitting it with my right arm. It's gone back to my opponent. It's coming back to me again. I'm going at it with my left on my backhand.

[Rachel Carlson]

Adrian's an imaginary tennis pro, so he kind of has this whole action sequence going.

[Gina]

I don't actually play much tennis, but I do play it in my mind

[Rachel Carlson]

quite Often when he does this with people like you and me, healthy, conscious patients, he sees activity in their brains related to movement, as if they're actually playing tennis.

[Regina Barber]

So what happened in this woman's brain?

[Rachel Carlson]

He saw the exact same thing.

[Gina]

Her brain activity was indistinguishable from a completely walking, talking, healthy person.

[Regina Barber]

Wait, so she was conscious of.

[Rachel Carlson]

I mean, she couldn't move, but she seemed to know what he was asking her to do, and her brain responded just like ours would. I know it seems pretty wild, but later studies with a lot more patients in vegetative states showed around 20 to 25% had similar responses.

[Regina Barber]

That's a large percentage.

[Rachel Carlson]

Yeah. And that's why techniques like Adrian's imagination test are getting a lot more attention in consciousness research. As of right now, clinicians don't have one standard way of deciding who is or isn't aware unless that person can use their words or their bodies. Okay, but some neuroscientists are asking what it would mean if there was a test that did exactly that.

[Regina Barber]

So today on the show Measuring Consciousness, you're listening to Shortwave, the science podcast from NPR.

[Rachel Carlson]

Foreign.

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[Regina Barber]

So, Rachel, we're talking about consciousness, but I'm not totally sure I know exactly what that word describes.

[Rachel Carlson]

So you're not alone. There's not really one answer, but when I asked researchers, I sort of got answers like this.

[Philosopher Tim Bain]

What's consc? It's the experience we're having right now,

[Neuroscientist Liad Mudryk]

what it is like, you know, to eat chocolate or to look at the

[Neuroscientist Marcello Massimini]

blue sky, everything that fades when I fall into dreamless sleep.

[Philosopher Tim Bain]

I think the best way to define consciousness is the way you might go about defining jazz. You don't try and give a musical definition in terms of theory or rhythm or chord progression or instrumentation. You play, you know, you play some jazz.

[Neuroscientist Liad Mudryk]

What it is like to be you

[Rachel Carlson]

and what it all really boiled down

[Neuroscientist Anil Seth]

to was, without consciousness, there really isn't anything at all. I mean, life matters to us because we're capable of having experiences.

[Regina Barber]

So consciousness is everything. Like our experiences, our emotions. Yeah, okay.

[Rachel Carlson]

Pretty much. It's not just one thing. Like, even in your daily cycle or my own, we're going through different stages of consciousness. Right. Like I'm dreaming or I'm starting to wake up or I'm falling asleep. You know, it's a spectrum. And that's exactly what makes the idea of deciding who is or isn't conscious so hard, even for you and me, and especially for people in vegetative states like the woman we heard about earlier, when they can't just tell us what they're experiencing or other states like comas.

[Gina]

Yeah.

[Rachel Carlson]

So Anil Seth, a neuroscientist at the University of Sussex in the uk says if we could understand this better or if we could have some kind of measurement, it would completely change how we understand people in the position. Like that woman, her quality of life.

[Neuroscientist Anil Seth]

We humans, we're moral agents in that we make decisions about how to treat other systems. And one of the criteria for making those decisions is whether or not that other system is conscious or capable of. Of consciousness.

[Regina Barber]

But like you said earlier, researchers are experimenting with new ways to get information about these different levels of experience. Right. Yeah.

[Rachel Carlson]

So we heard about one of those ways. That's the imagination test.

[Regina Barber]

Yeah, the tennis.

[Rachel Carlson]

Yes, that's like the tennis test we heard about from Adrian earlier, asking people to imagine doing something and then just seeing how their brain reacts.

[Regina Barber]

Okay.

[Rachel Carlson]

Another method combines two things. One is a magnet that stimulates the brain, and then the other part is a measurement of activity in the brain.

[Regina Barber]

Ooh, I want to hear about this magnet.

[Rachel Carlson]

Yeah. That magnet is basically meant to disturb a brain a little bit, because neuroscientists know that if you disturb a healthy brain with something like a magnet, it responds.

[Regina Barber]

I'm trying to imagine this. So it's like if you touch a block of jello and it, like, jiggles.

[Rachel Carlson]

Yeah. There's, like, the cause and effect. So the idea was to try this with people in vegetative states to see if their brains responded like healthy brains.

[Neuroscientist Anil Seth]

So it's a little bit like banging on the brain with an electrical hammer, and you listen to the echo.

[Rachel Carlson]

I talked about this with one of the people who've been at the forefront of this project, Marcello Massimini, a neuroscientist and a doctor. And he says once you disrupt the brain a little, you measure the echo it creates.

[Neuroscientist Marcello Massimini]

You are kind of looking for an orchestra that is well trained, trained, and, you know, super cohesive with different instruments and different partitions.

[Rachel Carlson]

So in theory, the more conscious someone is, the more complex and cohesive that symphony would sound. So it's sort of like all the different regions of their brain are working in harmony, but if they are disconnected,

[Neuroscientist Marcello Massimini]

they don't hear each other, they don't play along together. You're going to have something that is maybe just local and not propagated to the orchestra.

[Rachel Carlson]

Marcello co founded a company building a device that does this.

[Regina Barber]

So what do other researchers think about this test?

[Rachel Carlson]

The ones I spoke to were generally pretty excited and optimistic about it, which was actually quite surprising for me because scientists who study consciousness usually disagree a lot.

[Neuroscientist Liad Mudryk]

I find it to be a very impressive test for consciousness, but it's one out of several. Also, the other tests that we have kind of to our disposal are also quite good. And I think that only by combining those tests and comparing between them will we be able to actually get closer to being able to detect consciousness.

[Rachel Carlson]

That's Liad Mudryk. She's a professor of neuroscience and psychology at Tel Aviv University at and she also co directs the CFAR Brain, Mind and Consciousness program with Anil Seth, who we heard from before.

[Regina Barber]

Okay, so she's saying this is one option, but we should use it with other things. Things like that imagination exercise we heard about earlier.

[Rachel Carlson]

Exactly.

[Regina Barber]

Okay.

[Rachel Carlson]

Plus, I will say most of these tests for consciousness are many years away from being used regularly.

[Gina]

Oh, okay.

[Rachel Carlson]

You know, they're complicated, they're expensive, and they're not the easiest to immediately apply in medical settings.

[Regina Barber]

I know we talked about the medical reasons attests for consciousness consciousness would be helpful, but I imagine this could go south, like, pretty quickly. So are there any reasons we shouldn't have tests like these?

[Rachel Carlson]

I definitely had that question too. I was thinking about, like, IQ tests and some of the ways those have not always been used for good. And Liad said it's true there are some really big ethical questions here. Since we often associate having consciousness with

[Neuroscientist Liad Mudryk]

having moral worth, every question we ask about consciousness is loaded with ethical implications. And definitely being able to detect consciousness has wide implications. So think about being able to detect Consciousness in fetuses, at what point in pregnancy does the fetus become conscious? That's a huge question that has a lot of implications.

[Rachel Carlson]

It's really a question that once we have an answer for ourselves, for humans, it immediately has really broad applications beyond

[Neuroscientist Liad Mudryk]

people being able to differentiate between animals who are conscious and animals who are not. And also in AI or one day in robots, what happens when we start thinking about those robots, as, you know, entitled to some ethical considerations when they become conscious?

[Rachel Carlson]

It's honestly overwhelming when you start unraveling it. So I also talked to a philosopher at Monash University. His name's Tim Bain, and he co directs the CFAR Brain, Mind and Consciousness program with Anil and Liad. And he agreed with Liad, but he also made this point.

[Philosopher Tim Bain]

When we treat certain animals in certain ways or certain machines in certain ways, we're assuming that they are or are unconscious. When a surgeon starts surgery on someone who's had a general anesthetic, they're assuming that the person's not. That they're not experiencing pain. And so you're better off doing your best to provide those assumptions with as solid a theoretical, scientific basis as you can.

[Regina Barber]

Okay. So we're always kind of making these assumptions anyway. So having a better way to measure it means that we'll have more data to work with.

[Rachel Carlson]

Yeah, that's kind of a version of what everyone I talked to said, and it does make sense to me. Like, if you think back to the story Adrian Owen told us at the beginning of this episode, doctors were making assumptions about what that woman was or wasn't experiencing, like whether she was in pain or whether or not she was aware of what they were doing or saying around her. Until Adrian did this tennis experiment with her. He told me that some patients he's talked to who've regained their ability to speak or move later, remembered everything that was happening around them.

[Regina Barber]

What?

[Rachel Carlson]

And that's definitely not true for everyone, but I do think it points to how important consciousness is when it comes to these very real decisions about someone's quality of life. Plus, Gina, everyone I spoke to was thinking about future uses for things like this, you know, like the tech camp of it all. And I feel like we're at this juncture in time where humans are really interested in exactly what it is that makes us human and if or how we're different from things like AI or robots. And consciousness is an emerging tension point in that discussion. So I kind of expect to see a lot more research in this area in the coming years.

[Regina Barber]

Rachel Carlson, thank you so much for bringing us the story. It's made me think about consciousness so much more.

[Rachel Carlson]

Thanks, Gina.

[Regina Barber]

This episode was produced by Rachel Carlson and Hannah Chin. It was edited by our showrunner Rebecca Ramirez, and it was fact checked by Tyler Jones. Robert Rodriguez was the audio engineer. I'm Regina Barber. Thank you for listening to Short Waves from npr.

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