If there’s one familiar sound whenever a volunteer tries out an interactive device that uses electrical muscle stimulation, it is probably laughter. Even for experienced users of the technology, the sensation of a machine controlling your body feels unnatural and strange. Something about the experience disrupts people’s sense of agency—the feeling of being in control of one’s actions—which could interfere with the technology’s potential to improve learning and make virtual reality more realistic.
As Asst. Prof. Pedro Lopes explored devices through a human-computer interface lens, first in his doctoral work at the Hasso Plattner Institute in Germany and now at the University of Chicago, he grew interested in whether agency can be measured, controlled or even restored during use of such devices. In two recent pioneering papers, Lopes and collaborators have been on the trail of agency, using everything from pitching machines to fMRI brain scanners.
“We started by asking the question: Does electrical muscle stimulation always have to feel that unnatural, or is there anything we can do to make it feel more in tune with your own volition?” Lopes said. “I think we just started to answer it, but there are infinite ways to look at this thing because it’s such a philosophical question.”
The research on agency started with a simple demo performed at a 2018 conference by Jun Nishida, now a postdoctoral researcher at the University of Chicago: Could electrical muscle stimulation help people catch a marker dropped by another person at short range?
It did, and as expected, most volunteers attributed the action to the machine, not their own reflexes. But a small minority of participants disagreed, saying that the stimulation, known as EMS, must not have been on because they caught the marker unassisted.