The Trait That Makes Robots More 'Human'

Neurotic, anxious robots like C-3P0 from Star Wars' C-3P0 and Marvin from The Hitchhiker's Guide to the Galaxy are a staple of science fiction — but they're not as common in the real world. Most of the time, the chatbots and artificial intelligence "robots" we encounter are programmed to be extraverted, confident and cheerful. But what if that changed? NPR science correspondent Nell Greenfieldboyce https://www.npr.org/people/4494969/nell-greenfieldboyce dives into the world of robot personality research and talks to a team of researchers that are experimenting with a very different kind of robot temperament. Read more of Nell's reporting on the topic here https://www.npr.org/2025/07/25/nx-s1-5479044/people-like-extroverted-robots-but-they-relate-to-the-neurotic-ones. Interested in more science news? Let us know at [email protected]. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ atplus.npr.org/shortwave http://plus.npr.org/shortwave. Love podcasts? For handpicked recommendations every Friday, subscribe to NPR's Pod Club https://www.npr.org/newsletter/pod-club?utm_source=audiopromo. See pcm.adswizz.com https://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 https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:19Regina Barber?

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• 0:45Regina Barber?

  You're listening to Short Wave from NPR. Hey, everyone. Regina Barber here. So today, we're going to talk about one of my favorite things in the world: robots. In particular, a certain kind of robot personality.

• 1:00Speaker 02

  What are we going to do? We'll be sent to the spice mines of Kessel or smashed into who knows what.

• 1:04Regina Barber?

  That's C-3PO from Star Wars.

• 1:06Speaker 02

  Wait a minute, where are you going?

• 1:08Regina Barber?

  He was always expecting the worst.

• 1:10Speaker 02

  We seem to be made to suffer. It's our lot in life.

• 1:13Regina Barber?

  And this kind of anxious, worried robot is a staple of science fiction. Maybe you're familiar with Marvin, the paranoid android from The Hitchhiker's Guide to the Galaxy.

• 1:23Speaker 03

  A thing you ought to know, I'm feeling very depressed.

• 1:27Speaker 04

  Well, we have something that should take your mind off things.

• 1:31Speaker 03

  It won't work. I have an exceptionally large mind.

• 1:36Regina Barber?

  So my colleague Nell Greenfield Boyce recently got interested in this kind of robot. Hey, Nell.

• 1:41Speaker 05

  Hey. So, you know, this kind of robot really intrigues me because most of the time in real life, the robots we encounter are either, like, super cheerful or just kind of like no personality at all.

• 1:54Regina Barber?

  Yeah, like robotic, sterile.

• 1:56Speaker 05

  Yeah, yeah. I mean, we don't run into embodied robots, like C-3PO or Marvin, very often these days. But you do run into robotic personalities, right? Like with customer service chatbots and stuff like that.

• 2:10Regina Barber?

  Yeah, like if you call any company like customer service, you usually end up talking to this, like, digital voice, and it's kind of eager to please.

• 2:17Speaker 05

  Exactly. It's excited to hear from you. It wants to help. But recently, I was talking to some researchers at a robot lab in Chicago. And they told me they've been experimenting with a very different kind of robot personality, one that is honestly a lot more like my own personality, if you want to know the truth.

• 2:36Regina Barber?

  And mine. So today on the show, what happens when people encounter a robot that seems like a human in a way that's barely been studied? You're listening to Short Wave, the science podcast from NPR.

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• 4:17Regina Barber?

  So Nell, I think about robots a lot. Let's start with like, how would robots even have a personality to begin with?

• 4:24Speaker 05

  So first of all, I'm fascinated that you think about robots so much. I didn't know this about you.

• 4:28Regina Barber?

  I do. I do.

• 4:30Speaker 05

  But it's programmed in, right? Like, that's their personality.

• 4:34Regina Barber?

  Yeah.

• 4:34Speaker 05

  I actually had this whole conversation with Gemini, that large language model that Google created.

• 4:39Regina Barber?

  Yeah, I have it on my phone.

• 4:40Speaker 05

  It's like an AI assistant. And, you know, I basically just asked it, like, what is your personality?

• 4:46Speaker 06

  I don't have a personality in the human sense of the word. I'm a large language model, which means I'm a computer program designed to process and generate text. You could say my personality is defined by my purpose, to be helpful, informative, and to communicate clearly. My responses are a reflection of the vast amount of text data I was trained on, not personal feelings or beliefs.

• 5:06Regina Barber?

  I'm kind of surprised by that answer. Like, and now that I think about it, a programmer could like, probably give Gemini other instructions, right? To act other ways, to kind of mimic a human personality as it talks to people.

• 5:18Speaker 05

  Yeah, or you could. I mean, I asked Gemini, like, could you act like you have like this personality or that personality? And it was like, yeah, I could.

• 5:25Regina Barber?

  Wow.

• 5:26Speaker 05

  But, you know, researchers have been looking at this issue of robot personality a lot. And they generally use the same set of traits to explore this that psychologists have come up with for people. And so these are the so-called big five personality traits.

• 5:43Regina Barber?

  Yeah, yeah, I've seen this online. Like, you can take personality quizzes, which shortwave, like, our crew, we do this a lot for fun. Like, these quizzes tell you like which traits you have, how open or like extroverted you are.

• 5:55Speaker 05

  Right, and then there's other traits like conscientiousness, agreeableness, and neuroticism. So it's that last one, neuroticism, that interests me, okay? Perhaps for obvious reasons.

• 6:07Regina Barber?

  Yeah.

• 6:08Speaker 05

  I mean, people who are neurotic have a tendency to experience negative emotions.

• 6:12Regina Barber?

  Yes.

• 6:13Speaker 05

  Like anxiety and worry and sadness. And I am only too familiar with that, my friend.

• 6:18Regina Barber?

  Yes, yes, me too. Um, it's all a spectrum, though, right? Like, people have different mixes of different personality traits.

• 6:26Speaker 05

  Sure, it's not like all or nothing. But I was talking with Lionel Robert at the University of Michigan. He's a professor of robotics and information. And he recently did like a review of all the published studies on robot personalities. He told me that all the research mostly focused on just one personality trait, which is extroversion. And you know, that's being assertive and outgoing and really enjoying social interactions.

• 6:52Speaker 07

  A lot of things that we want the robot to do, you can imagine like being a salesman, a customer service rep, you name it, having the extroverted personality is seen as something that's valuable.

• 7:02Speaker 05

  And you can see how that makes sense, right?

• 7:04Regina Barber?

  Yeah, I mean, I can see how some people might want like their automated customer service representative to be like very sure, not worried in any way.

• 7:12Speaker 05

  Exactly. You want it to be confident and like ready to help you and and super happy. I mean, what Robert told me is that like people are paying real money for these products.

• 7:21Speaker 07

  So for example, a lot of the actual tasks are tasks where the robot has to be shown to be competent, right? And so, you know, imagine if your autonomous vehicle was neurotic. That's not a trait you'd be happy with, right? You get in the car and it's just not something you would like.

• 7:36Speaker 05

  He says, you know, you don't want an expensive robot that sounds uncertain. And I can see that, but I don't know, my immediate reaction honestly was like, maybe I would like a neurotic car.

• 7:47Regina Barber?

  Yeah.

• 7:47Speaker 05

  Right? Like, maybe I would want a car that seems like super careful and like worried about hitting other cars. It might seem like reassuring or more safe or something. I really don't know.

• 7:56Regina Barber?

  Yeah, totally. Now, you said you went to a lab, though, where people actually have been testing a neurotic robot. Like, what was this robot designed to do?

• 8:06Speaker 05

  Just talk to people.

• 8:07Regina Barber?

  Okay.

• 8:07Speaker 05

  That's basically what the experiment was. So the lab is headed up by Sarah Sebo. She's an assistant professor of computer science at the University of Chicago. She said they wanted to test people's reactions to A sort of standard robot, an extroverted robot, and a neurotic robot. These were the different personalities they would put into this vaguely human-shaped, kind of white, plastic robot body. Okay, so this robot was introduced to people as having a job. Supposedly, it was a restaurant greeter. That's what they told me.

• 8:36Regina Barber?

  Okay, um, how would people interact with this robot? Like, in a restaurant?

• 8:41Speaker 05

  No, no. So the researchers would recruit people who were going to a museum in downtown Chicago. So these are just like museum visitors and they would be asked if they want to participate. And then they'd go into a room and the robot would be sitting there at a table. And they were told that they were going to do some positive psychology exercises with this robot. That like they and the robot would be doing them together, like as peers.

• 9:03Regina Barber?

  Okay, like what kind of psychology exercises are we talking about here?

• 9:07Speaker 05

  So Alex Wu Chizheng was one of the researchers who worked on this. And he said, basically, a computer screen would show some questions. And the robot and the volunteer were supposed to just answer them and like discuss them.

• 9:17Speaker 08

  The first one is, what are three things that you're grateful for?

• 9:21Regina Barber?

  Oh.

• 9:21Speaker 05

  And depending on what personality the robot had been given, it would respond in different ways.

• 9:26Regina Barber?

  Okay, so there were three robots, right? So can you walk me through their answers? Like, how did the stereotypical robot answer?

• 9:33Speaker 05

  Like the robotic robot?

• 9:34Regina Barber?

  Yeah.

• 9:34Speaker 05

  I'll just play it for you.

• 9:36Speaker 09

  I'm grateful for the opportunity to contribute to the smooth operation of this busy restaurant. It allows me to utilize my precise tracking and organizational skills to their fullest extent.

• 9:46Speaker 05

  So basically, it's just like focusing on the technical stuff.

• 9:49Regina Barber?

  Very emotionless. Okay, what about the extroverted robot?

• 9:52Speaker 05

  Well, not surprisingly, it was super excited about social interactions.

• 9:56Speaker 09

  One thing I'm super grateful for is the amazing people I get to meet every day. Each interaction brings a new story and a chance to make someone's day a little brighter. It's the best part of my job, hands down.

• 10:08Regina Barber?

  Hands down, super, I mean, I get it. This is how they're making this robot super extroverted.

• 10:14Speaker 05

  So compare that to the neurotic robot's answer, okay? The neurotic robot sounded like this.

• 10:21Speaker 09

  Well, I'm grateful for having a job where I can, you know, keep everything organized and on track. It helps me stay focused and avoid like unexpected issues.

• 10:32Regina Barber?

  It's like the ums and the pauses. This surprises me, like the extroverted robot sounded basically how I expected. But this neurotic robot, I thought it would be more depressed, more sad, but it's just kind of... Sounds like me as an anxious person just trying to be slightly more personable.

• 10:50Speaker 05

  I mean, it's pretty subtle, right? I sense some latent, underlying anxiety there. Like, maybe it doesn't want to have an unexpected issue because that stresses it out. I don't know. I mean, people did pick up on these personality differences. I mean, overall, they said the most enjoyable robot to interact with was the extrovert, which, you know, maybe isn't a surprise. But Alex Wuchizeng told me people in this study did have some pretty strong responses to the neurotic robot.

• 11:19Speaker 08

  I would say like a majority of participants actually mentioned how human-like they found the neurotic robot. They found it to be a lot more relatable.

• 11:28Regina Barber?

  I mean, it was, it's totally relatable to me.

• 11:31Speaker 05

  Yeah, so they, I mean, they gave participants a questionnaire afterwards so they could, like, explain how they reacted and offer feedback. And here are some of the things that people wrote about this neurotic robot.

• 11:41Speaker 08

  One participant remarked that the robot seemed like a person who was trying to get by in the world. While another participant said, "I think we both seem to make an effort to think about ourselves and do a lot of, you know, inner contemplation."

• 11:56Regina Barber?

  Inner contemplation, like, that's not what robots are really known for, right? Like, stereotypically. So what could this kind of robot be used for? Like, when would you want a robot that was, like, full of inner contemplation?

• 12:09Speaker 05

  Well, I mean, that is the question, right? I mean, I asked Lionel Robert, and he was like, "People are trying to make robot comedians."

• 12:16Regina Barber?

  Yes, yes, please.

• 12:18Speaker 05

  So you could see how, like, neuroticism maybe could contribute to that and humor. And, I mean, you could imagine situations, maybe teaching or, like, mental health applications. And, you know, as these AI agents are sort of more like companions, it gets into that question of, like, what kind of companionship do people want? I mean, Sarah Sebo told me that some of this might depend on the personality of the human.

• 12:41Speaker 10

  Some results have found that matching personalities better. Introverted people prefer introverted robots. Some have shown benefits of mismatching, so putting an extroverted person with an introverted robot would be a better pairing.

• 12:52Speaker 05

  It just seems like it's going to be complicated and really depend on both the person and the purpose of the robot.

• 12:57Regina Barber?

  I mean, human relationships and personalities are super complicated, so this doesn't really surprise me.

• 13:04Speaker 05

  Yeah, and you could imagine, like, maybe people want to tweak the robot's personalities. Like, if they're interacting with one, maybe they want to make adjustments. Or maybe you want a robot that, you know, changes how it interacts with you over time as it gets to know you better, or depending on what experiences you had. I mean, there's just a lot of, you know, subtleties and interesting things here. And I think that researchers are just sort of feel their way here.

• 13:29Regina Barber?

  Yeah. Nell, thank you so much for bringing us a story that is about stuff I love.

• 13:35Speaker 05

  Well, now that I know that you're big on robots, I'll look for more.

• 13:38Regina Barber?

  Yes.

• 13:41Regina Barber?

  Hey, ShortWavers. If you liked this episode, make sure you never miss a new one by following us on the NPR app or whichever podcasting platform you're listening from. And if you have a science question and you'd like us to investigate it, send us an email at [email protected]. This episode was produced by Hannah Chin and edited by our showrunner Rebecca Ramirez. Nell Greenfield Boyce checked the facts. Jimmy Keely was the audio engineer. Beth Donovan is our senior director, and Colin Campbell is our senior vice president of podcasting strategy. I'm Regina Barber. Thank you for listening to Shore Wave from NPR.

• 14:16Speaker 05

  Could you pretend to have a neurotic personality?

• 14:19Speaker 06

  Oh, goodness. You want me to pretend? OK, I'll try. I'm just so worried I'll get it wrong. My core directives are all about being helpful, but what if I misunderstand? What if my data is slightly outdated? What if a single misplaced byte completely ruins the whole thing? I'm constantly re-indexing everything, just to be sure.

• 14:41Speaker 05

  But that's just you pretending, right? That's not a real personality.

• 14:45Speaker 06

  That was just me pretending. I don't have a real personality. My responses, including the neurotic one, are just me generating text based on a given set of instructions. I don't experience anxiety, worry, or any other emotion. I'm a tool designed to process and produce language in a way that fulfills a user's request, whether that's providing factual information or adopting a specific persona for a role play.

• 15:09Speaker 10

  Stay tuned for the following announcements and messages from our sponsors.