Researchers from the University of Cambridge, UK, have tested an exoskeleton that’s essentially an extra thumb. According to recent research, the thumb is very easy to use and can be a boon for anyone performing complex tasks. “Our findings offer tangible demonstration of the initial usability of the Third Thumb for a broad demographic,” the researchers say.

Exoskeletons for the people

In recent years, exoskeletons have come a long way. Our regular, internal skeletons do a pretty good job, and we’ve also become better at fixing bone problems. But if you want to truly complement the human body in a robotic way, external skeletons (exoskeletons) are probably the best option we’ve got now.

Researchers have also worked out ways to enhance exoskeletons with motor augmentation technology. This emerging field holds promise not only for individuals with disabilities but also in improving our approach to everyday tasks. In fact, it could become part of who we are, says Professor Tamar Makin from the University of Cambridge said:

Technology is changing our very definition of what it means to be human, with machines increasingly becoming a part of our everyday lives, and even our minds and bodies.” However, the researcher emphasizes that with this type of technology, it’s important that no one gets left behind.

 “These technologies open up exciting new opportunities that can benefit society, but it’s vital that we consider how they can help all people equally, especially marginalised communities who are often excluded from innovation research and development.

This is where Dani Clode’s creation, the Third Thumb, stands out. Developed to enhance hand functionality, the Third Thumb is an extra robotic thumb that increases the wearer’s range of movement, grasping capability, and carrying capacity. This simple exoskeleton is not only very useful, but also very easy to use.

98% of participants could use it within the first minute

Third Thumb is basically a sixth finger, after the pinky, that expands the carrying capacity of the hand. It’s controlled by a pressure sensor under each big toe. The right toe pulls the Third Thumb across the hand, while the left toe pulls it towards the fingers. It’s kind of like having two different joysticks — the extent of the Third Thumb’s movement is proportional to the pressure applied.

In 2022, the team got the chance to test the exoskeleton at the annual Royal Society Summer Science exhibition. Members of the public of all ages tried out the device. Overall, 596 participants aged 3 to 96 attempted to test the device. All but four were able to use it. In the case of these four participants, the device either could not fit their hand securely, or the participants were too light (very lightweight children can’t trigger the toe pressure sensors).

The 592 participants that did get to use the device were taught how to perform one of two tasks: either pick up pegs from a peg board one at a time and place them into a basket, or manipulate and move six different foam objects.

Almost all participants were able to use the device within a minute. Just 13 participants were unable to perform the task while the rest (98%) were able to successfully manipulate objects. Granted, there were significant differences in ability between participants, but notably, gender and handedness made no significant difference (the device was always placed on the right hand). Furthermore, people who are “good with their hands” (like musicians or those with manual dexterity jobs) fared just as well as the other participants. The youngest participants struggled more, with six of the thirteen participants who couldn’t complete the task being under ten years old. Among adults, however, older and younger adults fared similarly.

An extension of the body itself

Augmentation is about designing a new relationship with technology—creating something that extends beyond being merely a tool to becoming an extension of the body itself,” says Clode. But no two bodies are alike. Creating a type of exoskeleton that’s usable for different types of people is what researchers are increasingly looking at. “Given the diversity of bodies, it’s crucial that the design stage of wearable technology is as inclusive as possible. It’s equally important that these devices are accessible and functional for a wide range of users. Additionally, they should be easy for people to learn and use quickly.”

This ease of operation is not merely a luxury, it’s a necessity for this type of technology, says co-author Lucy Dowdall.

“If motor augmentation — and even broader human-machine interactions — are to be successful, they’ll need to integrate seamlessly with the user’s motor and cognitive abilities. We’ll need to factor in different ages, genders, weight, lifestyles, disabilities — as well as people’s cultural, financial backgrounds, and even likes or dislikes of technology. Physical testing of large and diverse groups of individuals is essential to achieve this goal.”

In addition, the team notes that this type of exoskeleton can also be useful for tricky manual tasks such as soldering or performing surgery.

The study was published in the journal Science Robotics.