It turns out that you can measure a person’s fear response. And anxiety. And perhaps other emotions. To figure this out, researchers needed to be able to reliably trigger these strong emotions in a setting where the participants’ reactions could be observed and measured. The researcher who nailed this particular challenge, Dr. Melis Yilmaz Balban, sees a lot of potential in using virtual reality experiences to mitigate anxiety or extreme fear responses. First, though, she’s exposing participants to VR simulations of situations where most humans would, indeed, feel fear or anxiety.
Her breakthrough discovery, though, came from research on mice, who have a reliable response to the fear triggered by an overhead predator. In the lab, Yilmaz Balban simulated an overhead predator, a hawk, for example, using a black disc that expands in size, as an approaching predator’s shadow would. Her study of the activity in mouse brains fueled her doctoral and post-doctoral research into neurological responses to fear.
It’s also the foundation of a new exploration into fear responses in humans that could lead to VR experiences that teach people—and allow them to practice—healthy behavioral responses to debilitating fear or anxiety reactions. This behavior-changing VR treatment could help people whose PTSD or extreme anxiety makes it difficult or impossible for them to participate in normal daily activities.
VR allows triggering—and addressing—fear response
The project, in its early stages, uses the Huberman Lab at Stanford University. The VR experiences include simulations using 360-degree photography of climbing 250 feet up a tree, swimming with sharks, being trapped in an elevator, and being attacked by a dog. The head of the lab, Dr. Andrew Huberman, collected much of the frightening footage himself.
These scary VR experiences provide a way to trigger and measure the participants’ response. “The first step is to understand what is the healthy range [of response] and what is the not healthy fear, objectively,” Yilmaz Balban said. “Nobody has really looked at the baseline: How do humans normally respond to this kind of thing?”
The project, still in early stages, aims to “create objective biomarkers of unhealthy fear and anxiety disorders,” she said, by measuring skin conductance response, heart rate, respiration, pupil size, and general behavior. Once the range of normal responses is understood, the next step would be to work on ways to “bring back those parameters that are ‘off’ to normal” in people with generalized anxiety disorders.
A lot depends on the stimulus, Yilmaz Balban said. For mice, overhead predators are an obvious, and consistent, fear trigger. Humans tend to be inconsistent in their responses to most stimuli, but “we have identified one stimulus, which is the heights, where I can say 90 percent of the people have a very reliable skin conductance response to the stimulus. It’s not behavior, but there is one parameter at least, the skin conductance response, that is very time-locked to this stimulus,” she said. That means that most people will show, at a minimum, a measurable skin response while looking down from a great height—real or virtual. This easily reproducible VR experience offers a “handle” or basis to compare the response of people who have a diagnosed anxiety disorder with those who do not, she said.
“The length of the response is different,” Yilmaz Balban said. A normal fear response subsides when the trigger ceases or is removed: You climb down from the tree or finish crossing the plank (or exit the VR experience); the snarling dog goes away. A pathological response or trauma-induced reaction lasts longer than the stimulus. Behavior changes too, she said, with “fidgety” participants less able to focus on cognitive games even after exiting the VR environment. These are the responses that Yilmaz Balban ultimately hopes to help mitigate with her research.
An opportunity for behavior change
Once Yilmaz Balban has identified an objective range of measurements for healthy and unhealthy fear and anxiety responses, behavioral therapists could create VR interventions that help participants change their response. Using VR offers two significant advantages:
- VR experiences can be highly personalized. “In VR, you can create any environment. You can tailor the environment to the person’s needs and then create behavioral choices that are alternative to what they normally do, for instance for addiction—and then train people for the other choice, for the better choice,” Yilmaz Balban said.
- VR offers immediacy. “The problem with therapy is that you have an event, you feel bad, you talk, you go out in the real world—and then it happens again. You have to remember what the therapist said and … it’s just hard for that to work. The brain doesn’t work like that. The brain works in millisecond time scale,” Yilmaz Balban said. In a VR environment, the behavioral therapy—the coached, healthy response—can occur at the moment the fear response is triggered. “We have a precise time where we can interfere with neural stimulation or even behavioral therapy,” she said.
These qualities create a visceral experience for participants that can feel very real.
Yilmaz Balban hopes to harness the abilities of VR to study the neurological responses to other stimuli, moving beyond fear. It could be possible to create profiles of other emotions, such as excitement, measuring the same neural and physical responses, such as a skin conductance response, pupil dilation, or heart rate increase, she said. “What we’re trying to do is create objective measures around emotion in general or internal states.” She’s also looking at brain activity to find correlating neural activity, which can help researchers distinguish fear from excitement. Observable behavior also provides clues as to whether a response is fearful or excited. “A lot goes on in the brain that gives us that feeling,” she said. “There is a neural correlate to everything. The ultimate goal is to understand that.”