Human hands have had 10 digits for millions of years.
But they look like scientists at the The University of Cambridge believes this is not enough.
The experts have created the ‘Third Thumb’: a steerable prosthesis that attaches to the edge of the right hand.
It allows wearers to pick up objects, open drinking bottles, search playing cards and even peel a banana – all with just one hand.
In their study, human volunteers quickly became accustomed to the extra digit – which “could push our motor abilities beyond current biological limitations.”
Cambridge researchers have shown that people have little difficulty learning very quickly how to use a third thumb: a controllable, prosthetic extra thumb
The study was led by Tamar Makin, professor of cognitive neuroscience at the University of Cambridge, and published in Science Robotics.
Professor Makin and colleagues think the thumb could be particularly valuable for amputees who, for example, have lost an arm and have difficulty performing everyday tasks with just one hand.
“Technology is changing our definition of what it means to be human,” they say in their article.
‘Machines are increasingly becoming part of our daily lives and even of our minds and bodies.
‘An exciting area for future technology is motor augmentation, which is designed to improve or extend people’s physical capabilities.’
The third thumb is worn on the opposite side of the palm from a person’s real thumb and is controlled by a pressure sensor placed under each big toe or foot that fits inside a shoe.
Pressure from the right toe pulls the prosthetic finger over the hand, while pressure applied with the left toe pulls it toward the fingers and releasing the pressure returns it to its original position.
Allows wearers to pick up objects, open drinking bottles, search playing cards and even peel a banana – all with just one hand
The extra figure could “bring our motor capabilities beyond current biological limitations,” the experts think
In their study, the team tested 596 participants, ranging in age from three to 96 years old, who were given one minute to familiarize themselves with the device.
The thumb came in different sizes to fit the hands of children and adults.
The participants performed two tasks: first, picking up pegs and placing them in a basket, and second, manipulating and moving five or six different foam objects of varying sizes.
Overall, the thumb was worn and controlled successfully by 99.3 percent of the sample, the researchers found.
And 98 percent of participants were able to successfully manipulate objects using the Third Thumb during the first minute of use.
Older and younger adults had similar levels of skill in using the device, although further research within the age range of older adults revealed a decline in performance with advancing age.
Third Thumb came in different sizes to fit the hands of children and adults
“This effect could be due to the general decline in sensorimotor and cognitive skills associated with aging,” the team says.
‘Additionally, these effects may also reflect a generational relationship with technology.’
It’s unclear when and how the academics might make their device available to the public, or how much it would cost.
But they hope it can “pave the way to setting a benchmark” for other “inclusive” human-centric devices.
“Future augmentation technologies could have a major impact on society and be useful to many people,” they write.