Researchers at Ecole Polytechnique Fédérale de Lausanne have found that virtual reality (VR) affects children differently than adults. The new research is key given how little work has been done in this area, for both adults and children.
Interesting Observation on VR
Back in 2016, EPFL graduate Jennifer Miehlbradt made an interesting observation. Miehlbradt allowed users to pilot drones on her VR by moving their torsos to navigate through a series of obstacles on a virtual landscape.
“Adults had no problem using simple torso movements to fly through the virtual obstacles, but I noticed that children just couldn’t do it,” said Miehlbradt. “That’s when Silvestro asked me to come to his office.”
At the time, Miehlbradt was being supervised by Silvestro Micera, Bertarelli Foundation Chair in Translation Neuroengineering. The pair realized that there was more to the VR torso experiment and that it could be revealing something about the development of a child’s nervous system. At that point, there had been no study in the literature on the effect of VR headsets on children.
With this in mind, the team decided to set out and study this over several years, collaborating with the Italian Institute of Technology. The study involved 80 children between the ages of 6 and 10, and the results were published last month in Scientific Reports.
“This study confirms the potential of technology to understand motor control,” says Micera.
Adults are easily able to disconnect their head movements from their torso for piloting, similar to the way they ride a bike. This process involves the complex integration of multiple sensory inputs, such as vision from the inner ear for balance, and proprioception, which is the body’s ability to sense movement, action and location.
For children, they are still developing their coordination of torso and head movement, which makes them different from adults right away. One of the interesting findings in this study is that it goes against the ontogenetic model that has been used for 25 years to describe the development of upper body coordination. This model predicts a one-directional transition from rigid control to a decoupling of the head-torso system, and it indicated that postural control is mature at 8 years.
Miehlbradt is currently finishing a postdoc at the University of Lausanne (UNIL).
“The model states that from the acquisition of walking around 1 year until 6-7 years, children will control their upper body as a whole with rigid links between the trunk, head and arms. After this age, the children gradually learn to control all their joints independently, but resort to the rigid strategy in challenging conditions,” continues Miehlbradt. “Instead, we found that when using a virtual system controlled by body movements, the younger children try to move their head and body separately, while the adults use the rigid strategy.”
Results of the Experiments
The experiment carried out by the team involved placing a VR headset and a movement sensor on the child as they were asked to play two games. In both of the experiments, the children demonstrated control abilities similar to adults’ when using their head. However, they were not able to keep up with adults when it came to using their torso to control.
The children were first asked to align their head and torso with a line displayed at different orientations within a virtual landscape. At the same time, the alignment error and head-torso coordination were measured. The experiment demonstrated that children can master head control fairly easily, but whenever they were asked to align their torso with the virtual line, the youngest children overestimated their movements and attempted to compensate by moving their heads.
In the second game, the children were asked to participate in a flight scenation. The child is seated on the back of a flying eagle in the virtual world, and they are tasked with catching golden coins that are placed along a path. The children once again had a much easier time controlling the bird’s flight with their head.
To the scientists, all of this indicated that head control is easier in VR environments because the desired orientation is aligned with the visual input. When it comes to the torso control, this requires the user to separate vision from the actual control, which requires head-torso coordination. Young children rely on visual input more than internal sensation of body posture, and the VR environment can quickly overwhelm a child’s brain.
“The results show that immersive VR can disrupt the children’s default coordination strategy, reweighting the various sensory inputs — vision, proprioception and vestibular inputs — in favor of vision,” explains Miehlbradt.
“VR has been gaining in popularity, not only for leisure but also for therapeutic applications such as rehabilitation and neurorehabilitation, or the treatment of phobias or fearful situations. The diversity of scenarios that can be created and the playful aspect that can be brought into otherwise cumbersome activities make this technology particularly appealing for children, and we should be aware that immersive VR can disrupt the child’s default coordination strategy,” Miehlbradt says.