The Human Computer Integration Lab's smartwatch that is activated by slime mold

It’s alive! The Human Computer Integration Lab’s novel smartwatch is activated by an organism called Physarum polycephalum. (Photo courtesy Jasmine Lu)

Connect with slime mold

A living smartwatch tracks the bond between people and their devices.

Do you have a smartphone in your pocket or a smartwatch on your wrist? For many of us, our devices are constant companions—only to be ditched when a newer model is released. In 2021 a record 63 million tons of electronic waste were discarded worldwide, of which only 17 percent was recycled. But what if we developed emotional relationships with our devices like we do with our pets, wondered Jasmine Lu. Would we be so quick to abandon them?

Lu is a computer science PhD student in assistant professor Pedro Lopes’s Human Computer Integration Lab, which focuses on engineering interactive devices that integrate directly with a user’s body. Lopes’s research is a more immersive take on human-computer interaction, a field that explores the interfaces between people and technologies.

To probe the potential for a more caring bond with our electronics, Lu designed a smartwatch integrated with a living organism: a slime mold. The device, which tells time and monitors heart rate, works only when the slime mold is healthy. The wearer must care for the device, like a living Tamagotchi—the Japanese virtual pets popular in the ’90s. Lu didn’t set out to reimagine the egg-like toy, but after creating the slime mold watch, she recognized the similarities to her childhood virtual pet. She would feed it in the morning and bring it to school, hooked on her belt loop, she says. “I treasured it.”

Why a slime mold? Despite the name, it’s not like other types of mold, explains Lu. Slime molds are now known to be part of the protist kingdom—a diverse collection of mostly single-celled organisms distinct from fungi, plants, animals, and bacteria. The species Physarum polycephalum was chosen because it can rapidly grow toward food sources, which is how it is able, curiously, to solve mazes. Nicknamed “the blob,” the species is also resilient, able to go dormant when starved and to be revived even years later.

The slime mold lives in a transparent enclosure on the watch, and the wearer must give it oats and water on a regular schedule. When properly cared for, the slime mold will grow across a channel to reach oats on the other side of the enclosure, forming a living wire that conducts electricity and activates the device. (Electricity travels through the slime mold, but the current is low enough that the team didn’t observe any harm to its body; it continued to thrive, says Lu.)

The two-week study involved five participants and was split into phases: “caring” and “neglect.” Throughout the process, the participants kept a diary of the care they provided, the slime mold’s condition, and their own reflections. They were interviewed after each phase.

For the caring phase, they were asked to wear the watch for as much of the day as possible, watering the slime mold twice a day and feeding it oats every other day. All participants noted a sense of connection with the watch, and four described it as a little friend or pet. One named her slime mold Jeff. (The participants sometimes talked about the slime mold as a separate entity rather than part of the device, something Lu and Lopes hope to change with an updated design.)

One woman was reminded that her device had a life-form inside by its earthy smell and associated the healthy slime mold’s bright yellow color with happiness. Another linked the watch’s needs to her own: whenever she ate, she would check the slime mold. Yet another recounted how she was sick during part of the care phase, and her partner fed her oatmeal. “She started calling me her slime,” wrote the participant, because “we were eating the same stuff.”

The participants were then told to withhold water and food. Unsurprisingly, all five mentioned how much easier the second phase was; they felt relieved and disconnected. But each participant also felt sad or guilty while neglecting their slime mold. One woman who had eagerly shown off her living watch felt anxious about having to explain the slime mold’s neglected state. While the dried-out slime mold was technically dormant, many participants referred to it as dead.

The team collected the watches after the experiment, but in the exit interview, they asked hypothetically, “How would you dispose of the watch?” Responses included: toss the watch and keep the slime mold; sell it; and give it to a friend. “If you really couldn’t take care of a pet anymore,” said one of the participants, “you would try to rehome it.”

All participants identified as women, which was not a deliberate experimental design choice. Lu speculates there may have been some self-selection—many women grew up with toys where “caretaking is the central modality that they’re expected to engage with.” Tamagotchis were aggressively marketed toward girls, and four of the five participants happened to have direct experience with virtual pets. But “it was a small set of people,” says Lopes, “so you can’t generalize too much.” In the future, says Lu, “it would be interesting to explore this from a gendered perspective.”

Of course, slime mold watches will likely never catch on like Tamagotchis, nor was Lu suggesting with this research that biological devices are the practical solution to e-waste. Rather, exploring interactions between people and their living technology might teach engineers how to center a sense of care in their interactive designs. If engineers could make it easier to repair rather than replace devices, for instance, people with less computing or electronics literacy “might feel more empowered,” says Lu—more comfortable learning how devices work and exactly what they’re doing.

Lopes compares repairing your own device to people learning to bake bread during the pandemic. You could buy a mass-produced loaf at the store, “but folks are discovering some deeper connection by making their own.” You could buy the latest iPhone, but if you repair or upgrade the one you already have, it’s no longer the sole creation of Apple, says Lopes. In some ways, “it becomes partly yours.”

Consumer devices “are made so that you trash them, instead of engaging with them,” Lu told UChicago Computer Science News. “So I definitely think there is a design takeaway of focusing on this aspect of caring for devices instead of just consuming them.”