Scientists have discovered that people can feel bionic tools, such as tweezers, as extensions of their own body in virtual reality (VR). This improves their task performance and dexterity. The study was published on June 6 in the journal iScience.
It was conducted by cognitive neuroscientists Ottavia Maddaluno from Sapienza University of Rome and the Santa Lucia Foundation IRCCS, alongside Viviana Betti. The researchers found that participants were faster and more precise in completing motor tasks in VR with bionic tools resembling tweezers than with a virtual human hand. For our biology to merge seamlessly with tools, we need to feel that the tools are part of our body,” says Maddaluno.
Our findings demonstrate that humans can experience a grafted tool as an integral part of their own body.
In the VR environment, participants were given either a human-like hand or a bionic tool resembling a pair of tweezers grafted onto their wrist. Their task was to pop bubbles of a specific color by pinching them with the tweezers or between their index finger and thumb. Results indicated that participants performed faster and more accurately with the tweezer-hands.
The researchers used a “cross-modal congruency task” to compare implicit embodiment between the virtual hand and the bionic tool.
Tweezers enhance dexterity in VR
Small vibrations were applied to the participants’ fingertips while a flickering light was displayed on the VR screen, either matching or mismatching the tactile stimulus.
Participants were faster and more accurate at identifying the stimulated fingers when the visual and tactile stimuli matched, indicating a sense of embodiment for both the human hand and the tweezer-hands. The sense of embodiment was stronger with the tweezer-hands. The researchers suggest this could be due to the simplicity of the tweezers, which might make it easier for the brain to accept and compute.
Additionally, the “uncanny valley” hypothesis may play a role, as the virtual human hands might be too similar yet distinct to feel perfectly embodied. The team also tested other bionic tools, such as a wrench-shaped tool and a virtual hand holding tweezers. They found evidence of embodiment in all cases.
However, the sense of embodiment and dexterity were highest when the tweezers were directly grafted onto the virtual wrists. The next step is to study if these bionic tools could be embodied in patients that have lost limbs,” says Maddaluno. We also want to investigate the plastic changes that this kind of bionic tool can induce in the brains of both healthy participants and amputees.
This research highlights the potential for integrating bionic tools into human biology.
It paves the way for advancements in prosthetic limb technology and robotics.
