This Halloween weekend, people all over the country will walk into haunted houses knowing exactly what they are getting into. The zombies are actors, the blood is fake, and the chainsaw is a prop, yet the moment something lunges out of the dark, hearts pound, hands fly up, and someone screams loud enough to make the rest of the group laugh. Researchers who study recreational fear describe this as a form of play, a way to experience fear and the emotions that come with it without any real cost or danger (Andersen et al.).
The interesting part is that knowing it's fake doesn't switch the response off. That gap between what the mind knows and what the body does is exactly what virtual reality taps into, and researchers have spent more than two decades measuring it, from simulated pits that make hearts race to simulated ledges that change the way people stand.
What may surprise people is that rehabilitation researchers have started putting that gap to work on purpose. Carefully controlled, simulated threats are being studied as a way to help people face a fear of falling, rehearse the balance reactions they need when something unexpected happens, move again after fear has taught them to avoid it, and build skills that hold up under pressure. In this post, we walk through the science of why a good scare works on the brain and body, and how immersive therapy is turning that science into a rehabilitation tool.
Your Brain Knows It's Fake, but Your Body Didn't Get the Memo
In a widely cited 2009 paper, Mel Slater of the EVENT Lab at the University of Barcelona set out to explain why people tend to respond realistically to situations they know are simulated. He described two separate ingredients. The first, which he calls place illusion, is the sensation of actually being in a place, and it depends on the environment responding to your body the way the real world would, so that turning your head, leaning, or looking down changes what you see in the way you expect. The second, which he calls plausibility illusion, is the sense that the events in front of you are really happening, and it depends on whether those events respond to you and how believable the scenario feels compared with what you would expect (Slater).
The most important detail in Slater's framework is one that every haunted house visitor already understands. In both illusions, the person knows for certain that they are not really there and that the events are not really occurring, yet Slater argues that when both illusions are present, people respond realistically anyway (Slater). That is the haunted house effect in a sentence, because nobody walking through Dystopia or any other scare attraction believes the zombie is real, but the actors there improvise and react to each group as they move through the rooms (Andersen et al.), which makes the scare plausible enough for the body to respond before the mind can talk it down.
Immersive therapy can supply both ingredients at once. Inside a virtual reality headset, head tracking makes the space respond the way a real room would, and well-designed therapy tasks, like reaching for an object or working through an everyday routine, make events respond to the patient doing them. When that combination works, the environment doesn't need to fool anyone to produce a genuine reaction, which is the foundation immersive therapy is built on. Researchers have found some clever ways to measure exactly how genuine that reaction can be, and Halloween fans will appreciate the first one.
The Pit Room: Measuring a Scare With a Heart Rate Monitor
One of the most famous scares in immersive research came out of a computer science lab at the University of North Carolina at Chapel Hill, and it was built a lot like a haunted house. Participants started in an ordinary training room, practicing walking around and picking up objects, and were then asked to carry an object into the next room. When the door opened, they found an unguarded hole in the floor dropping 20 feet to a furnished living room below, with only a 2-foot-wide walkway around the edge (Meehan et al.).
The researchers reported that users said they felt frightened, some described vertigo, and some refused to step onto the ledge at all and asked to stop at the doorway, while a few walked straight out over the hole as if the floor were made of glass, even though the real lab floor was flat and solid the entire time (Meehan et al.).
To measure the reaction, the team tracked heart rate, skin conductance, and skin temperature as participants moved from the safe room into the pit room. Heart rate climbed by an average of 6.3 beats per minute in the pit room compared with the training room, and change in heart rate proved to be the most sensitive of the three measures (Meehan et al.). For perspective, the authors pointed to earlier research in which people with a fear of heights who climbed a real fire escape and looked down saw their heart rate rise by an average of 13.4 beats per minute. Their own participants had no fear of heights and were facing a simulated drop, so a smaller response in the same direction was exactly what the researchers expected to find (Meehan et al.).
Three details from that work matter for rehab. Adding a 1.5-inch wooden ledge that participants could feel under their toes made the heart rate response stronger, raising the average increase from 4.9 beats per minute without the ledge to 7.6 with it, which means the more closely an environment matches what the body feels, the more genuine the reaction becomes (Meehan et al.). The reaction faded somewhat over as many as 12 visits spread across four days, but it never dropped to zero (Meehan et al.). Most telling of all, at the lowest frame rate the team tested, participants often lost their balance while inching toward the edge, and their heart rate jumped an average of 3.5 beats per minute each time it happened (Meehan et al.), which is a vivid reminder that a believable environment doesn't only change how people feel, it also changes how they move.
Why a Scare Sticks: Fear, Emotion, and Memory
Ask someone about a haunted house they visited years ago, and they will usually skip the hallways and go straight to the moment something jumped out at them. The Aarhus haunted house study captured a version of this, since visitors asked about the three filmed scares right after they exited remembered those specific moments in nearly 94 percent of cases (Andersen et al.). A review published in Frontiers in Psychology explains why that happens, summarizing substantial evidence that emotional events are remembered more clearly, more accurately, and for longer than neutral ones (Tyng et al.).
The brain mechanics behind that effect are well mapped. When emotional information is being encoded, the amygdala and the hippocampus become active together, and the amygdala strengthens consolidation, which is the process that turns a fragile new memory into a lasting one, while the prefrontal cortex helps encode and organize what is being learned (Tyng et al.). Emotionally intense experiences also trigger the release of stress hormones that act on the amygdala and further strengthen consolidation, and emotional stimuli tend to grab attention ahead of everything else, using up more of the brain's limited attentional resources than neutral information does (Tyng et al.).
Surprise plays a role of its own. The same review describes surprise as a mismatch between what a person expected and what actually happened, a mismatch that pulls attention toward whatever caused it, and it describes curiosity as a state that prepares the brain to learn and remember (Tyng et al.). A jump scare is surprise in its purest form, which helps explain why it lands so hard and stays so long.
The dose matters a great deal, though. According to the review, mild and short-lived stress tends to help learning and performance, while excessive or chronic stress impairs learning and harms memory (Tyng et al.). That mirrors the haunted house research, where visitors enjoyed the scares more as fear rose to a moderate level and less once the scares became too intense (Andersen et al.). For rehabilitation, this is the whole reason any scare-based approach has to be brief, controlled, and graded, because a challenge that makes a patient's heart beat a little faster can help a lesson stick, while one that overwhelms them works against the very learning therapy is trying to build.
When a Simulated Drop Changes How People Stand
A racing heart is one thing, but balance is where this research starts to speak directly to rehab clinicians. Researchers in Mark Carpenter's balance lab at the University of British Columbia compared what happened when people stood at the edge of a real elevated platform with what happened when they stood at a simulated height built to match it in scale and visual detail. Participants responded to both versions in similar ways, with comparable shifts in how much and how quickly they swayed, along with similar changes in skin conductance, anxiety, fear, and confidence in their own balance (Cleworth et al.).
A follow-up thesis from the same lab tested what happens when the ground actually moves. Exposure to a simulated height significantly changed how participants' muscles responded when the surface beneath them shifted, and the author concluded that simulated height could produce responses similar to real height, making it a useful way to study balance problems tied to fear and anxiety in people who already have a fear of falling (Cleworth). That matters because, as the same work points out, fear of falling and fall risk are strongly related, and falls are a leading cause of injury among older adults (Cleworth).
The effect isn't limited to healthy adults, either. In a 2026 study from the University Children's Hospital Basel, 22 children with cerebral palsy and 24 typically developing children stood on a simulated plank, first at ground level and then 10 meters above the virtual ground. Both groups reported feeling less stable and more afraid of falling at height, and the researchers concluded that simulated heights may change postural balance ("Postural Balance").
None of these studies set out to scare people for fun. Researchers use simulated heights because they offer a safe, repeatable way to see how threat changes the way people stand and move, without anyone ever being in real danger. The bigger lesson for rehab is that if a believable environment can change how someone balances while their feet never leave the floor, it can also give patients practice that their bodies treat as real.
Fear of Falling: Using a Simulated Threat to Treat a Real One
For a lot of rehab patients, the scariest thing in their lives isn't a zombie or a chainsaw, it's the thought of hitting the floor. Researchers in Paris describe fear of falling as an intense fear of standing or walking, an ongoing concern that leads people to avoid activities they are still physically capable of doing. They report that it affects roughly 24 to 55 percent of older adults, rising to between 24 and 92 percent among people who have already fallen, and that its consequences can include physical injuries, reduced quality of life, impaired social interaction, and even accidental death (Levy et al.).
That team treated fear of falling the way clinicians treat other phobias, through gradual exposure, and they used virtual reality to do it. Sixteen older adults were randomly assigned either to treatment or to a waiting list, and the treatment group completed 12 weekly sessions of about 40 minutes each. Every session included a brief clinical interview, roughly 15 minutes of walking through simulated worlds that grew more challenging over time, starting with a level city sidewalk and progressing through a castle, an island, and an underground setting, followed by about 15 minutes of movement-based games such as washing a window covered in foam (Levy et al.). Fear of falling scores improved after treatment, with a significant difference between the treatment group and the waiting list, although the authors are clear that this was a small study and that further research is needed to confirm the effect (Levy et al.).
The most useful detail for clinicians came from what went wrong first. When the researchers initially tried simulated exposure on its own, patients walked carelessly afterward and were at risk of falling, which is why they added the movement games, to reconnect patients with what their bodies could actually do (Levy et al.). The authors also note that in conditions like Parkinson's disease, some fear of falling can be adaptive, so a specialist has to judge whether the fear matches the person's real walking difficulty (Levy et al.). The goal of a scare-based approach was never fearlessness, because the real target is a level of caution that matches a patient's real ability.
Training Under Pressure: Why a Little Fear in Practice Carries Over
Anyone who has walked a nervous patient up a curb or into a crowded lobby knows that a skill mastered in the therapy gym doesn't always survive the real world. Sports psychologists call the extreme version of this choking, and researchers at Vrije Universiteit Amsterdam wanted to know whether practicing with a little fear could prevent it. In one study, novices practiced throwing darts while hanging low on a climbing wall, either with or without mild anxiety, and were then tested under low, mild, and high anxiety, with the high-anxiety test taking place high up on the wall (Oudejans and Pijpers, "Training with Mild Anxiety"). Even though anxiety, heart rate, and perceived effort rose steadily from one test to the next, the group that had trained with anxiety performed equally well on all three, while the group that trained without it saw their performance drop under high anxiety (Oudejans and Pijpers, "Training with Mild Anxiety").
An earlier set of experiments with skilled performers found the same pattern, with performance holding up under pressure only after people had practiced under anxiety. The authors concluded that practicing with anxiety helps prevent choking because performers get used to the specific changes that come along with feeling anxious (Oudejans and Pijpers, "Training with Anxiety").
These studies involved dart throwers, not rehab patients, so they aren't proof that the same thing happens after a stroke or a joint replacement. They do, however, offer a strong explanation for a problem clinicians see all the time, which is that practice under perfectly calm, predictable conditions may not prepare someone for the moments in daily life that come with nerves attached, like crossing a busy intersection, stepping onto an icy porch, or showering at home for the first time after discharge. Immersive therapy makes it possible to add mild, controlled pressure to practice, such as a busier environment, a time limit, or a distraction, so patients can get used to performing while a little nervous before they have to do it for real.
Expecting the Unexpected: Surprise Slips and Trips in Balance Training
Haunted houses run on surprise, because the whole point is that you never know when the next door will swing open or what is waiting around the corner. Rehabilitation has its own version of that idea, called perturbation-based balance training, which uses repeated, deliberate disturbances to a person's balance to improve control of the rapid reactions that keep them upright (Mansfield et al.). In practice, those disturbances can come from a moving platform, a treadmill, or a well-timed nudge from a therapist.
A team from the University of Toronto and the Toronto Rehabilitation Institute pooled the early evidence in a 2015 systematic review and meta-analysis published in Physical Therapy. Across eight randomized controlled trials involving 404 older adults and people with neurological conditions, participants who completed perturbation-based training were less likely to report a fall and reported fewer falls overall than those in the control groups (Mansfield et al.). The authors concluded that this kind of training appears to reduce fall risk among older adults and people with Parkinson's disease, while describing the trials as preliminary and calling for more research (Mansfield et al.).
The reasoning behind it is simple once you think about where falls actually happen. Very few people fall during a planned exercise with a therapist standing beside them, and far more fall when something unexpected happens, like a slick spot on the kitchen floor, a curb that is higher than it looked, or a dog darting between their feet. Training the body to respond to surprise prepares it for those moments in a way that predictable practice cannot. Immersive environments add a visual dimension to the same idea, since the pit room and height studies show that what people see can shift their balance and heart rate even when the floor beneath them never moves (Meehan et al.; Cleworth et al.). That doesn't make a headset a substitute for hands-on perturbation training, but it does show why the element of surprise deserves a place in balance rehab.
Facing a Fear of Movement: Graded Exposure for Chronic Pain
Not every fear in rehab involves heights or falls. Many people living with chronic pain develop kinesiophobia, a fear of movement rooted in the worry that moving will bring more pain or another injury. Researchers working within the Department of Veterans Affairs describe re-engaging patients in the movements they fear as a primary goal of chronic pain rehabilitation, while acknowledging that it is hard to do, because even safe movement can feel physically and emotionally uncomfortable (Fowler et al.).
One research team found that people with chronic low back pain and high pain-related fear specifically avoid bending forward at the lower back, so they built a virtual dodgeball game designed to draw out gradually more of that bending while lowering expectations of pain and harm, using a competitive, entertaining game to do it. Participants in the game group played 15 minutes of virtual dodgeball on three consecutive days (Thomas et al.). Later reviewers noted that the study reported high acceptability, with no participants withdrawing and no adverse events (Fowler et al.).
The VA has taken the idea further. A feasibility study at the James A. Haley Veterans' Hospital's Chronic Pain Rehabilitation Program was designed to give up to 20 Veterans immersive sessions as part of their physical therapy, organized as a ladder that moves from low-intensity distraction, like sitting in a chair during a guided meditation, to more interactive graded exposure, like standing and using full-body movement to paint (Fowler et al.). The authors pointed to an earlier randomized study in which adding guided virtual walking to physical therapy significantly reduced fear of movement and pain intensity compared with physical therapy alone, and they grounded the approach in the fear-avoidance model, which holds that as people gradually confront feared activities, the beliefs driving that fear are challenged and the fear response fades (Fowler et al.).
The "scare" in this kind of therapy looks nothing like a jump scare. It is a patient facing the exact movement they have been avoiding, in small steps, inside an environment safe enough to try it, which mirrors what the pit room researchers saw when reactions faded a little with each repeated visit, even though the drop itself never changed (Meehan et al.).
Why Realism Is What Makes the Scare Work
Every rehab clinician knows the gap between the clinic and real life. The therapy gym is quiet, well lit, flat, and predictable, while a patient's kitchen, a grocery store, or a busy parking lot is none of those things. Thomas Parsons of the University of North Texas describes a long-running tension in the neurosciences between ecological validity, meaning how well an assessment reflects real-world activity, and experimental control, noting that traditional tests often rely on simple, static tasks that leave out much of what real situations demand (Parsons). His review argues that immersive virtual environments can bridge that gap by combining the control of a laboratory with realistic, engaging scenarios that unfold over time (Parsons).
The scare research shows why that bridge holds weight. Slater's work explains why people respond realistically to simulated situations (Slater), the pit room shows that the response reaches all the way to the heart (Meehan et al.), and the height studies show it reaches posture and balance too (Cleworth et al.). Put together, the research suggests that when a patient reaches, steps, turns, or shifts their weight inside a believable immersive therapy environment, the reactions they use are much closer to the ones they would need at home than a rehearsed movement in an empty room.
Context matters for learning as well. In a study of adults with Parkinson's disease, the benefits of more demanding practice showed up most clearly when participants were tested in the same context where they had practiced (Onla-or and Winstein), which is a strong argument for practicing in settings that look and feel like the places patients are actually trying to get back to.
That is the real lesson hiding inside a haunted house. Every approach in this post, from simulated heights to virtual dodgeball, depends on the environment being believable enough for the brain and body to take it seriously. A threat the body doesn't believe teaches it very little, while a believable one draws out the same reactions, the same caution, and the same courage a patient will need when they face the real thing.
Keeping the Scare Safe: Graded, Consented, and Clinician-Controlled
Scare-based rehab only works when it looks nothing like an ambush. The approaches in this post share a few common features, starting with exposure that begins small and builds gradually, like the Paris team's worlds of increasing difficulty (Levy et al.) and the VA's ladder from distraction to active exposure (Fowler et al.). Choice matters just as much as pacing. At the haunted house, visitors who came because they wanted to enjoyed the experience more than those who came along for someone else (Andersen et al.), and in a clinic, that translates to patients understanding and agreeing to any challenge that is designed to make them a little nervous.
Physical safety needs the same attention. The pit room researchers saw participants lose their balance while inching toward the edge at the lowest frame rate they tested (Meehan et al.), and the fear of falling study found that patients walked carelessly after simulated exposure on its own (Levy et al.). Both are reminders that any immersive balance or mobility work calls for the same guarding, positioning, and screening a clinician would use for any other challenging task, along with real-world practice to connect what happens in the headset to what happens on solid ground.
The dose has to fit the person, too. Mild, short-lived stress tends to support learning, while excessive or chronic stress works against it (Tyng et al.), and patients living with anxiety disorders or trauma histories, including veterans whose service experiences can make sudden surprises distressing, need careful screening and may be better served by approaches with no startle element at all. The VA protocol's decision to start with calm distraction before moving toward exposure reflects exactly that kind of judgment (Fowler et al.), and it is a reminder that the person guiding the session, not the simulation, decides how much challenge is right.
A Quick Note on Smart Therapy™: Joy Instead of Fright
Smart Therapy™ doesn't use scare tactics or include any scary games, but it does draw on the same science from the other direction, since emotion helps the brain hold onto an experience whether that emotion is fear or fun. The review behind much of this post notes that curiosity prepares the brain to learn and remember, and that some studies find positive emotions support learning by boosting motivation and satisfaction (Tyng et al.). That is why Smart Therapy™ is built around engaging, game-based activities and everyday scenarios that patients genuinely enjoy, so the joy of hitting a target or finishing a task gives each session's practice a better chance of sticking, while the therapist adjusts the challenge in real time from a tablet that shows exactly what the patient sees.
The Science of a Good Scare
When someone screams in a haunted house this weekend, they will be proving something researchers have measured for more than twenty years, which is that a convincing environment reaches past what we know and changes what our bodies do. Hearts speed up at simulated drop-offs, posture shifts at heights that exist only inside a headset, and the emotional jolt of a well-timed surprise helps a moment stick in memory long after the lights come back on.
Rehabilitation researchers are learning to put that same science to work, with carefully graded exposure that helps people face a fear of falling, surprise perturbations that train the reactions that prevent falls, mild pressure that prepares patients for nerve-racking moments in daily life, and virtual games that coax people back into movements they have been afraid to make. In the right dose and in the right hands, a little fear can become a genuinely useful tool in rehab. If you'd like to see how clinicians use Smart Therapy™ to make immersive therapy engaging and memorable, visit neurorehabvr.com/smart-therapy-complete-solution to learn more.
Happy Halloween from all of us at Neuromersive!
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