Captain of her high school tennis team and a four-year veteran of college tennis in college, Amanda Studnicki had been training for this moment for years.
All he had to do now was think small. Like small ping pong.
For weeks, Studnicki, a graduate student at the University of Florida, served and faced off against dozens of players on a table tennis court. His opponents sported a sci-fi face, a cap of electrodes coming off their heads in a backpack as they played Studnicki or a ball service machine. That cyborg appearance was vital to Studnicki’s goal: to understand how our brains react to the intense demands of a high-speed sport like table tennis, and what difference a machine opponent makes.
Studnicki and his adviser, Daniel Ferris, found that the brains of table tennis players react very differently to human or mechanical opponents. Faced with the inscrutability of a ball-throwing machine, the players’ brains scrambled in anticipation of the next serve. While with the obvious signs that a human opponent was about to serve, his neurons buzzed in unison, seemingly confident in his next move.
The findings have implications for sports training, suggesting that human opponents provide a realism that cannot be replaced by machine helpers. And as robots become more common and sophisticated, understanding our brain’s response could help make our artificial companions more naturalistic.
“Robots are becoming more ubiquitous. There are companies like Boston Dynamics that are building robots that can interact with humans and other companies that are building welfare robots that help the elderly,” said Ferris, a professor of biomedical engineering at UF. “Humans interacting with robots will be different than when they interact with other humans. Our long-term goal is to try to understand how the brain reacts to these differences.”
Ferris’s lab has long studied the brain’s response to visual cues and motor tasks, such as walking and running. He was looking to upgrade to studying fast-paced, complex action when Studnicki, with his tennis background, joined the research group. So the lab decided that tennis was the perfect sport to address these questions. But oversized moves, especially high overhead serves, proved to be an obstacle to burgeoning technology.
“So we literally narrowed things down to table tennis and asked the same questions that we had before for tennis,” Ferris said. The researchers had yet to compensate for the smaller movements in table tennis. So Ferris and Studnicki doubled the 120 electrodes on a typical brain scan cap, with each additional electrode providing a check for rapid head movements during a match of table tennis.
With all these electrodes scanning the players’ brain activity, Studnicki and Ferris were able to tune into the region of the brain that converts sensory information into movement. This area is known as the parieto-occipital cortex.
“It takes all your senses (visual, vestibular, auditory) and provides information on how to create your motor plan. They’ve been studied a lot for simple tasks, like reaching and grabbing, but they’re all stationary,” Studnicki said. “We wanted to understand how complex movements work, like following a ball through space and intercepting it, and table tennis was perfect for this.”
The researchers analyzed dozens of hours of play against Studnicki and the ball machine. When playing against another human, the players’ neurons worked in unison, as if they all spoke the same language. By contrast, when the players faced a machine that pulled out balls, the neurons in their brains were not aligned with each other. In the world of neuroscience, this misalignment is known as desynchronization.
“If we have 100,000 people in a football stadium and they’re all cheering together, it’s like a synchronization in the brain, which is a sign that the brain is relaxed,” Ferris said. “If we have those same 100,000 people but they’re all talking to their friends, they’re busy but out of sync. In many cases, that desynchronization is an indication that the brain is doing a lot of calculations instead of sitting and idling.”
The team suspects that the players’ brains were so active while waiting for the robotic serves because the machine gives no clues as to what they are going to do next. What is clear is that our brains process these two experiences very differently, suggesting that training with a machine might not offer the same experience as playing against a real opponent.
“I still see a lot of value in practicing with a machine,” Studnicki said. “But I think the machines are going to evolve in the next 10 to 20 years, and we might see more natural behaviors for players to practice.”