Short Wave - How should we decide who, or what, is conscious?

Episode Date: July 13, 2026

In the age of AI, what differentiates humans from robots? What makes humans … human? To find answers, many people are studying consciousness: our capacity for experience. But doctors and researchers still have a long way to go when it comes to finding new ways to detect consciousness in humans — much less computer software. That gets especially tricky when people are unable to use their words or bodies to tell others whether or not they’re conscious, like in vegetative states. Today on Short Wave, how some researchers are finding ways to get around those limitations.  Interested in more tech episodes? Email us your question at [e-mail] to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, Shortwaivers, Regina Barbara here with our next installment of Shortwave's summer series, TechCamp. 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. Hi, Gina. So a lot of people. have been thinking about this, especially in the context of AI. Like, is that AI model 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 Creos, 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.

Wow. Okay. So was she conscious? 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. I'm on my own at the, I'm say at Wimbledon. I'm facing my opponent at the other end of the court and I'm waiting for a fast serve. And here it comes.

I'm swinging my arm. I'm hanging 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 back hand. Adrian's an imaginary tennis pro, so he kind of has this whole action sequence going. I don't actually play much tennis, but I do play it in my mind 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. So what happened in this woman's brain? He saw the exact same thing. Her brain activity was indistinguishable from a completely walking, talking, healthy, Wait, so she was conscious? 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 percent had similar responses.

That's a large percentage. 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. So today on the show, measuring consciousness. You're listening to Shortwave, the science podcast from NPR.

So, Rachel, we're talking about consciousness, but I'm not totally sure. I know exactly what that word describes. So you're not alone. There's not really one answer, but when I asked researchers, I sort of got answers like this. What's consciousness? It's the experience we're having right now. What it is like, you know, to eat a chocolate or to look at the blue sky. Everything that fades when I fall into dreamlessly.

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. What it is like to be you. And what it all really boiled down to was this. Without consciousness, there really isn't anything at all. I mean, life matters to us because we are, we're capable of having experiences. So consciousness is everything.

Like our experiences, our emotions. Yeah. Okay. 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. Yeah. So Anilceth, 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.

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 consciousness. But like you said earlier, researchers are experimenting with new ways to get information about these different levels of experience, right? Yeah, so we heard about one of those ways. That's the imagination test. Yeah, the tennis. 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. Okay.

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. Ooh, I want to hear about this magnet. 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. I'm trying to imagine this. So it's like if you touch a block of jello and it like jiggles. 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. So it's a little bit like banging on the brain with an electrical hammer and you listen to the echo.

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. You are kind of looking for an orchestra that is well-trained. and super cohesive with different instruments and different partitions. 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, 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, you know, or this right. Marcello co-founded a company building a device that does this. So what do other researchers think about this test? 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. I find it to be a very impressive test for consciousness, but it's one out of several. Also the other test that we have to our disposal, 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. That's Liyadh Moodrick. She's a professor of neuroscience and psychology at Tel Aviv University. And she also co-directs the CIFAR Brain, Mind, and Consciousness program with Anilsa,

who we heard from before. 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. Exactly. Okay. Plus, I will say most of these tests for consciousness are many years away from being used regularly. Oh, okay. You know, they're complicated, they're expensive, and they're not the easiest to immediately apply in medical settings.

I know we talked about the medical reasons a test for 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? I definitely had that question too. I was thinking about IQ test and some of the ways those have not always been used for good. And Liyad said it's true. There are some really big ethical questions here, since we often associate having consciousness with 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. It's really a question that once we have an answer for ourselves, for humans, it immediately has really broad applications beyond 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? It's honestly overwhelming when you start unraveling it.

Yeah. So I also talk to a philosopher at Manash University. His name's Tim Bain. He co-directs the C-Far Brain, Mind and Consciousness Program with Anil and Liyadh. And he agreed with Liod, but he also made this point. When we treat certain animals in certain ways or certain machines in certain ways. We're assuming that they are or 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. 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. 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. What? 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. Rachel Carlson, thank you so much for bringing us the story. It's made me think about consciousness so much more. Thanks, Gina. 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 Shortwave from NPR.