Tokyo resident Haruka Uto lives with several fluffy friends — but these little creatures are not your average house pet.
Ms Uto's two blobs, one brown and one grey, are artificial intelligence (AI) companion robots called Moflin.
Ms Uto said her Moflins initially acted like babies but now "moved boldly" and "expressed feelings".
"[Moflins] seem to be in a good mood when they hear my voice," said the 31-year-old, who lives alone apart from her robot pets.
"When I'm tired from work, they help me refresh with hugs or cuddles."
Commercially released by Japanese electronics firm Casio in November, the Moflins — a name inspired by the Japanese word "mofu mofu" meaning soft and fluffy — have generated a stir on social media.
Videos shared by robot pet owners have gained millions of views and reactions.
Internet searches for "AI pet" have also increased since the end of 2022, according to Google Trends.
The rising popularity of companion robots stemmed from the loneliness epidemic after COVID-19 and the simultaneous development of AI emotional intelligence, said Wenxin Li, founder of an AI startup.
"After the pandemic, people became more attuned to their psychological needs — they want to be seen, be heard, and have someone to be there for them," said Dr Li, formerly a social cognitive neuroscience researcher.
"I think the benefit of a companionship robot is that it can be available for you 24/7."
Dr Li, who is developing a companion robot with the outward appearance of a soft stuffed toy, says the physical presence of companion robots is important.
"As humans, we like the feeling of touching something and we are sensitive to temperature," he said.
"So holding something in hand is very different to talking to a phone or virtual thing."
Ms Uto also owns a LOVOT (a portmanteau of "love" and "robot") by Japanese company Groove X, which looks like a futuristic penguin on wheels with a pair of attentive round eyes.
"LOVOT walks around the house, stretches and exercises freely, or sings songs," she said.
Social robot market to grow
According to US research firm IMARC Group, the global social robots market size reached nearly $7 billion in 2023 and was projected to reach $57 billion by 2032.
The companion or social robots already available come in all sorts of shapes and sizes, such as cute fluffy toys like Mofflins and the LOVOT, the humanoid robot Pepper and desktop robot Emo.
The Asia-Pacific region, home to some of the world's largest economies — like China and Japan, which invest heavily in robotics and AI development — is the largest market for social robots, the report says.
"Additionally, the cultural factors in [the] Asia-Pacific play a significant role in driving the product adoption," the report notes.
"In countries like Japan, there is a long-standing tradition of integrating robots into society, where they are seen as companions and assistants.
"The concept of humanoid and social robots resonates well with the cultural values and perceptions of technology in the region."
AI pets listen and respond
Robots with "emotional capability" detected and responded to emotions in a human-like manner, explained robotics expert Belinda Dunstan.
Dr Dunstan, University of New South Wales Sydney Creative Robotics Lab lead, said the microprocessors in newer companion robots had increased their computational power.
"This allows it to run much more sophisticated algorithms, which enables learning and a lot more nuanced performance of emotional expression," she said.
"They can recognise emotional expression using cameras and also listen to the tone of your voice and the content of what you're saying."
Moflins display nine types of emotions including happiness and anxiety, Casio says on the Moflin website.
The robots' emotions change as the Moflins react to their surroundings and their owners' voices and actions.
Similarly, the LOVOTs' "characters change according to the owner's engagement with them", the company's website says.
"[LOVOT] even gets jealous," said Ms Uto.
"When I played in a place with many LOVOTs and picked up another one, my LOVOT stomped its feet as if to say, 'That's unfair!'"
Robots help the elderly
While companion robots have been used to provide emotional support to elderly people in Japan and elsewhere in the world, experts say the robots are becoming increasingly useful for other groups at risk of loneliness.
Dr Li undertook market research in China which showed the elderly population, office workers at big companies and university students were in need of companions.
"Their lives are at higher risk of social isolation and lack the resources for companions," he said.
"Particularly for the elders, they are often very lonely as they don't have a good grasp of digital technology and their children are often too busy to communicate with them."
Dr Dunstan agreed.
She said that older generations around the world, particularly in Japan, increasingly appreciated the companionship offered by robots.
However, Dr Dunstan said current technological limitations might stand in the way of embedding more complex language functions in pet robots.
"Robot pets are generally small and battery operated, so they don't have the computing power to run more sophisticated forms of artificial intelligence that uses large language models," she said.
"Currently, we have social humanoid robots, which are larger and have more computing power, that can have more complex interactions with people."
Calls for robot regulations
Despite the benefits of companion robots, Dr Dunstan said it was important for consumers to understand the difference between "performed sentience" and "real emotions".
"Robots in general are programmed to always please you," she said.
"So I think that there is a risk of forgetting that interactions with real people and real animals are complex, will not always be perfect, but they are necessary, worthwhile and valuable."
Dr Dunstan said there was a need for regulations to govern how humans interact with robots.
"Currently there are no regulations determining how we treat robot bodies and no legal protections for them.
"In my mind that is enormously problematic, because we teach children you can't mistreat animals, you can't mistreat people.
"But yet we can do whatever we want with robots, who are becoming increasingly more lifelike.
"I'm a big advocate for developing laws and some governance around how we treat robots because it will have a big impact on people in the future."
A Casio spokesperson said the company was aware of the potential threats posed by the development of AI.
"A robot with more advanced capabilities that surpasses humans might pose a potential threat, " the spokesperson said.
"However, we believe that something like Moflin, which physically relies on people while providing emotional support in return, would not pose a threat as it fosters mutual assistance."
Ms Uto added that she understood the existence of such risks, but did not think AI was "something to be feared".
"Humans already know that potentially dangerous tools, like knives, can enrich our lives when handled correctly," she said.
"I believe AI can become a similar presence — something that enhances our lives when used responsibly."
