Virtual Reality: The New World inside your phones

When we talk about Virtual Reality (VR), many of us think of science fiction films like 'Minority Report'. However, the truth is that nowadays, this technology completely blends in with our daily lives. Video games, medicine, education... Virtual Reality is here to stay. But what is it exactly?

WHAT IS VIRTUAL REALITY?

virtual reality (VR), the use of computer modeling and simulation that enables a person to interact with an artificial three-dimensional (3-D) visual or other sensory environment. VR applications immerse the user in a computer-generated environment that simulates reality through the use of interactive devices, which send and receive information and are worn as goggles, headsets, gloves, or body suits. In a typical VR format, a user wearing a helmet with a stereoscopic screen views animated images of a simulated environment. The illusion of “being there” (telepresence) is effected by motion sensors that pick up the user’s movements and adjust the view on the screen accordingly, usually in real time (the instant the user’s movement takes place). Thus, a user can tour a simulated suite of rooms, experiencing changing viewpoints and perspectives that are convincingly related to his own head turnings and steps. Wearing data gloves equipped with force-feedback devices that provide the sensation of touch, the user can even pick up and manipulate objects that he sees in the virtual environment.

The term virtual reality was coined in 1987 by Jaron Lanier, whose research and engineering contributed a number of products to the nascent VR industry. A common thread linking early VR research and technology development in the United States was the role of the federal government, particularly the Department of Defense, the National Science Foundation, and the National Aeronautics and Space Administration (NASA). Projects funded by these agencies and pursued at university-based research laboratories yielded an extensive pool of talented personnel in fields such as computer graphics, simulation, and networked environments and established links between academic, military, and commercial work. The history of this technological development, and the social context in which it took place, is the subject of this article.

Education and training

An important area of application for VR systems has always been training for real-life activities. The appeal of simulations is that they can provide training equal or nearly equal to practice with real systems, but at reduced cost and with greater safety. This is particularly the case for military training, and the first significant application of commercial simulators was pilot training during World War II. Flight simulators rely on visual and motion feedback to augment the sensation of flying while seated in a closed mechanical system on the ground. The Link Company, founded by former piano maker Edwin Link, began to construct the first prototype Link Trainers during the late 1920s, eventually settling on the “blue box” design acquired by the Army Air Corps in 1934. The first systems used motion feedback to increase familiarity with flight controls. Pilots trained by sitting in a simulated cockpit, which could be moved hydraulically in response to their actions (see ). Later versions added a “cyclorama” scene painted on a wall outside the simulator to provide limited visual feedback. Not until the Celestial Navigation Trainer, commissioned by the British government in World War II, were projected film strips used in Link Trainers—still, these systems could only project what had been filmed along a correct flight or landing path, not generate new imagery based on a trainee’s actions. By the 1960s, flight trainers were using film and closed-circuit television to enhance the visual experience of flying. The images could be distorted to generate flight paths that diverted slightly from what had been filmed; sometimes multiple cameras were used to provide different perspectives, or movable cameras were mounted over scale models to depict airports for simulated landings.

Inspired by the controls in the Link flight trainer, Sutherland suggested that such displays include multiple sensory outputs, force-feedback joysticks, muscle sensors, and eye trackers; a user would be fully immersed in the displayed environment and fly through “concepts which never before had any visual representation.” In 1968 he moved to the University of Utah, where he and his colleague David Evans founded Evans & Sutherland Computer Corporation. The new company initially focused on the development of graphics applications, such as scene generators for flight simulator systems. These systems could render scenes at roughly 20 frames per second in the early 1970s, about the minimum frame rate for effective flight training. General Electric Company constructed the first flight simulators with built-in, real-time computer image generation, first for the Apollo program in the 1960s, then for the U.S. Navy in 1972. By the mid-1970s, these systems were capable of generating simple 3-D models with a few hundred polygon faces; they utilized raster graphics (collections of dots) and could model solid objects with textures to enhance the sense of realism (see computer graphics). By the late 1970s, military flight simulators were also incorporating head-mounted displays, such as McDonnell Douglas Corporation’s VITAL helmet, primarily because they required much less space than a projected display. A sophisticated head tracker in the HMD followed a pilot’s eye movements to match computer-generated images (CGI) with his view and handling of the flight controls.

Advances in flight simulators, human-computer interfaces, and augmented reality systems pointed to the possibility of immersive, real-time control systems, not only for research or training but also for improved performance. Since the 1960s, electrical engineer Thomas Furness had been working on visual displays and instrumentation in cockpits for the U.S. Air Force. By the late 1970s, he had begun development of virtual interfaces for flight control, and in 1982 he demonstrated the Visually Coupled Airborne Systems Simulator—better known as the Darth Vader helmet, for the armoured archvillain of the popular movie Star Wars. From 1986 to 1989, Furness directed the air force’s Super Cockpit program. The essential idea of this project was that the capacity of human pilots to handle spatial information depended on these data being “portrayed in a way that takes advantage of the human’s natural perceptual mechanisms.” Applying the HMD to this goal, Furness designed a system that projected information such as computer-generated 3-D maps, forward-looking infrared and radar imagery, and avionics data into an immersive, 3-D virtual space that the pilot could view and hear in real time. The helmet’s tracking system, voice-actuated controls, and sensors enabled the pilot to control the aircraft with gestures, utterances, and eye movements, translating immersion in a data-filled virtual space into control modalities. The more natural perceptual interface also reduced the complexity and number of controls in the cockpit. The Super Cockpit thus realized Licklider’s vision of man-machine symbiosis by creating a virtual environment in which pilots flew through data. Beginning in 1987, British Aerospace (now part of BAE Systems) also used the HMD as the basis for a similar training simulator, known as the Virtual Cockpit, that incorporated head, hand, and eye tracking, as well as speech recognition.

Sutherland and Furness brought the notion of simulator technology from real-world imagery to virtual worlds that represented abstract models and data. In these systems, visual verisimilitude was less important than immersion and feedback that engaged all the senses in a meaningful way. This approach had important implications for medical and scientific research. Project GROPE, started in 1967 at the University of North Carolina by Frederick Brooks, was particularly noteworthy for the advancements it made possible in the study of molecular biology. Brooks sought to enhance perception and comprehension of the interaction of a drug molecule with its receptor site on a protein by creating a window into the virtual world of molecular docking forces. He combined wire-frame imagery to represent molecules and physical forces with “haptic” (tactile) feedback mediated through special hand-grip devices to arrange the virtual molecules into a minimum binding energy configuration. Scientists using this system felt their way around the represented forces like flight trainees learning the instruments in a Link cockpit, “grasping” the physical situations depicted in the virtual world and hypothesizing new drugs based on their manipulations. During the 1990s, Brooks’s laboratory extended the use of virtual reality to radiology and ultrasound imaging.

Virtual reality was extended to surgery through the technology of telepresence, the use of robotic devices controlled remotely through mediated sensory feedback to perform a task. The foundation for virtual surgery was the expansion during the 1970s and ’80s of microsurgery and other less invasive forms of surgery. By the late 1980s, microcameras attached to endoscopic devices relayed images that could be shared among a group of surgeons looking at one or more monitors, often in diverse locations. In the early 1990s, a DARPA initiative funded research to develop telepresence workstations for surgical procedures. This was Sutherland’s “window into a virtual world,” with the added dimension of a level of sensory feedback that could match a surgeon’s fine motor control and hand-eye coordination. The first telesurgery equipment was developed at SRI International in 1993; the first robotic surgery was performed in 1998 at the Broussais Hospital in Paris.

Entertainment

As virtual worlds became more detailed and immersive, people began to spend time in these spaces for entertainment, aesthetic inspiration, and socializing. Research that conceived of virtual places as fantasy spaces, focusing on the activity of the subject rather than replication of some real environment, was particularly conducive to entertainment. Beginning in 1969, Myron Krueger of the University of Wisconsin created a series of projects on the nature of human creativity in virtual environments, which he later called artificial reality. Much of Krueger’s work, especially his VIDEOPLACE system, processed interactions between a participant’s digitized image and computer-generated graphical objects. VIDEOPLACE could analyze and process the user’s actions in the real world and translate them into interactions with the system’s virtual objects in various preprogrammed ways. Different modes of interaction with names like “finger painting” and “digital drawing” suggest the aesthetic dimension of this system. VIDEOPLACE differed in several aspects from training and research simulations. In particular, the system reversed the emphasis from the user perceiving the computer’s generated world to the computer perceiving the user’s actions and converting these actions into compositions of objects and space within the virtual world. With the emphasis shifted to responsiveness and interaction, Krueger found that fidelity of representation became less important than the interactions between participants and the rapidity of response to images or other forms of sensory input.

The ability to manipulate virtual objects and not just see them is central to the presentation of compelling virtual worlds—hence the iconic significance of the data glove in the emergence of VR in commerce and popular culture. Data gloves relay a user’s hand and finger movements to a VR system, which then translates the wearer’s gestures into manipulations of virtual objects. The first data glove, developed in 1977 at the University of Illinois for a project funded by the National Endowment for the Arts, was called the Sayre Glove after one of the team members. In 1982 Thomas Zimmerman invented the first optical glove, and in 1983 Gary Grimes at Bell Laboratories constructed the Digital Data Entry Glove, the first glove with sufficient flexibility and tactile and inertial sensors to monitor hand position for a variety of applications, such as providing an alternative to keyboard input for data entry.

Zimmerman’s glove would have the greatest impact. He had been thinking for years about constructing an interface device for musicians based on the common practice of playing “air guitar”—in particular, a glove capable of tracking hand and finger movements could be used to control instruments such as electronic synthesizers. He patented an optical flex-sensing device (which used light-conducting fibres) in 1982, one year after Grimes patented his glove-based computer interface device. By then, Zimmerman was working at the Atari Research Center in Sunnyvale, California, along with Scott Fisher, Brenda Laurel, and other VR researchers who would be active during the 1980s and beyond. Jaron Lanier, another researcher at Atari, shared Zimmerman’s interest in electronic music. Beginning in 1983, they worked together on improving the design of the data glove, and in 1985 they left Atari to start up VPL Research; its first commercial product was the VPL DataGlove.

By 1985, Fisher had also left Atari to join NASA’s Ames Research Center at Moffett Field, California, as founding director of the Virtual Environment Workstation (VIEW) project. The VIEW project put together a package of objectives that summarized previous work on artificial environments, ranging from creation of multisensory and immersive “virtual environment workstations” to telepresence and teleoperation applications. Influenced by a range of prior projects that included Sensorama, flight simulators, and arcade rides, and surprised by the expense of the air force’s Darth Vader helmets, Fisher’s group focused on building low-cost, personal simulation environments. While the objective of NASA was to develop telerobotics for automated space stations in future planetary exploration, the group also considered the workstation’s use for entertainment, scientific, and educational purposes. The VIEW workstation, called the Virtual Visual Environment Display when completed in 1985, established a standard suite of VR technology that included a stereoscopic head-coupled display, head tracker, speech recognition, computer-generated imagery, data glove, and 3-D audio technology.

The VPL DataGlove was brought to market in 1987, and in October of that year it appeared on the cover of Scientific American (see photograph). VPL also spawned a full-body, motion-tracking system called the DataSuit, a head-mounted display called the EyePhone, and a shared VR system for two people called RB2 (“Reality Built for Two”). VPL declared June 7, 1989, “Virtual Reality Day.” On that day, both VPL and Autodesk publicly demonstrated the first commercial VR systems. The Autodesk VR CAD (computer-aided design) system was based on VPL’s RB2 technology but was scaled down for operation on personal computers. The marketing splash introduced Lanier’s new term virtual reality as a realization of “cyberspace,” a concept introduced in science fiction writer William Gibson’s Neuromancer in 1984. Lanier, the dreadlocked chief executive officer of VPL, became the public celebrity of the new VR industry, while announcements by Autodesk and VPL let loose a torrent of enthusiasm, speculation, and marketing hype. Soon it seemed that VR was everywhere, from the Mattel/Nintendo PowerGlove (1989) to the HMD in the movie The Lawnmower Man (1992), the Nintendo VirtualBoy game system (1995), and the television series VR5 (1995).

Numerous VR companies were founded in the early 1990s, most of them in Silicon Valley, but by mid-decade most of the energy unleashed by the VPL and Autodesk marketing campaigns had dissipated. The VR configuration that took shape over a span of projects leading from Sutherland to Lanier—HMD, data gloves, multimodal sensory input, and so forth—failed to have a broad appeal as quickly as the enthusiasts had predicted. Instead, the most visible and successfully marketed products were “location-based entertainment” systems rather than personal VR systems. These VR arcades and simulators, designed by teams from the game, movie, simulation, and theme park industries, combined the attributes of video games, amusement park rides, and highly immersive storytelling. Perhaps the most important of the early projects was Disneyland’s Star Tours, an immersive flight simulator ride based on the Star Wars movie series and designed in collaboration with producer George Lucas’s Industrial Light & Magic. Disney had long built themed rides utilizing advanced technology, such as animatronic characters—notably in Pirates of the Caribbean, an attraction originally installed at Disneyland in 1967. Star Tours utilized simulated motion and special-effects technology, mixing techniques learned from Hollywood films and military flight simulators with strong story lines and architectural elements that shaped the viewers’ experience from the moment they entered the waiting line for the attraction. After the opening of Star Tours in 1987, Walt Disney Imagineering embarked on a series of projects to apply interactive technology and immersive environments to ride systems, including 3-D motion-picture photography used in Honey, I Shrunk the Audience (1995), the DisneyQuest “indoor interactive theme park” (1998), and the multiplayer-gaming virtual world, Toontown Online (2001).

In 1990, Virtual World Entertainment opened the first BattleTech emporium in Chicago. Modeled loosely on the U.S. military’s SIMNET system of networked training simulators, BattleTech centres put players in individual “pods,” essentially cockpits that served as immersive, interactive consoles for both narrative and competitive game experiences. All the vehicles represented in the game were controlled by other players, each in his own pod and linked to a high-speed network set up for a simultaneous multiplayer experience. The player’s immersion in the virtual world of the competition resulted from a combination of elements, including a carefully constructed story line, the physical architecture of the arcade space and pod, and the networked virtual environment. During the 1990s, BattleTech centres were constructed in other cities around the world, and the BattleTech franchise also expanded to home electronic games, books, toys, and television.

While the Disney and Virtual World Entertainment projects were the best-known instances of location-based VR entertainments, other important projects included Iwerks Entertainment’s Turbo Tour and Turboride 3-D motion simulator theatres, first installed in San Francisco in 1992; motion-picture producer Steven Spielberg’s Gameworks arcades, the first of which opened in 1997 as a joint project of Universal Studios, Sega Corporation, and Dreamworks SKG; many individual VR arcade rides, beginning with Sega Arcade’s R360 gyroscope flight simulator, released in 1991; and, finally, Visions of Reality’s VR arcades, the spectacular failure of which contributed to the bursting of the investment bubble for VR ventures in the mid-1990s.

Living in virtual worlds

By the beginning of 1993, VPL had closed its doors and pundits were beginning to write of the demise of virtual reality. Despite the collapse of efforts to market VR workstations in the configuration stabilized at VPL and NASA, virtual world, augmented reality, and telepresence technologies were successfully launched throughout the 1990s and into the 21st century as platforms for creative work, research spaces, games, training environments, and social spaces. Military and medical needs also continued to drive these technologies through the 1990s, often in partnership with academic institutions or entertainment companies. With the rise of the Internet, attention shifted to the application of networking technology to these projects, bringing a vital social dimension to virtual worlds. People were learning to live in virtual spaces.

The designers of NASA’s Visual Environment Display workstation cited the goal of putting viewers inside an image; this meant figuratively putting users inside a computer by literally putting them inside an assemblage of input and output devices. By the mid-1990s, Mark Weiser at Xerox PARC had begun to articulate a research program that instead sought to introduce computers into the human world. In an article titled “The Computer for the 21st Century,” published in Scientific American (1991), Weiser introduced the concept of ubiquitous computing. Arguing that “the most profound technologies are those that disappear” by weaving “themselves into the fabric of everyday life until they are indistinguishable from it,” he proposed that future computing devices would outnumber people—embedded in real environments, worn on bodies, and communicating with each other through personal virtual agents. These computers would be so natural that human users would not need to think about them, thus inaugurating an era of “calm technology.” If Weiser’s ubiquitous computing is thought of as complementary rather than opposed to VR, one can see traces of his ideas in a variety of post-VR systems.

A large group of systems involved projecting images in physical spaces more natural than a VR workstation. In 1992 researchers from the University of Illinois at Chicago presented the first Cave Automatic Virtual Environment (CAVE). CAVE was a VR theatre, a cube with 10-foot-square walls onto which images were projected so that users were surrounded by sights and sounds. One or more people wearing lightweight stereoscopic glasses walked freely in the room, their head and eye movements tracked to adjust the imagery, and they interacted with 3-D virtual objects by manipulating a wand-like device with three buttons. The natural field of vision of anyone in a CAVE was filled with imagery, adding to the sense of immersion, but the environment allowed greater freedom of movement than VR workstations, and several people could share the space and discuss what they saw.

Other examples of more natural virtual spaces included the Virtual Reality Responsive Workbench, developed in the mid-1990s by the U.S. Naval Research Laboratory and collaborating institutions. This system projected stereoscopic 3-D images onto a horizontal tabletop display viewed through shutter glasses. With data gloves and a stylus, researchers could interact with the displayed image, which might represent data or a human body for scientific or medical applications. The shift to projected VR environments in artistic and scientific work put aside the bulky VR helmets of the 1980s in favour of lightweight eyeglasses, wearable sensors, and greater freedom of movement.

Another important application of VR during the 1990s was social interaction in virtual worlds. Military simulation and multiplayer networked gaming led the way. Indeed, the first concerted efforts by the military to tap the potential of computer-based war gaming and simulation had taken shape in the mid-1970s. During the 1980s, the increasing expense of traditional (live) exercises focused attention on the resource efficiency of computer-based simulations. The most important networked virtual environment to come out of this era was the DARPA-funded SIMulator NETworking (SIMNET) project, begun in 1983 under the direction of Jack Thorpe. SIMNET was a network of simulators (armoured vehicles and helicopters, initially) that were linked together for collective training. It differed from previous stand-alone simulator systems in two important respects. First, because the training objectives included command and control, the design focused on effect rather than physical fidelity; psychological or operational aspects of battle, for example, required only selective verisimilitude in cabinet design or computer-generated imagery. Second, by linking together simulators, SIMNET created a network not just of physical connections but also of social interactions between players. Aspects of the virtual world emerged from social interactions between participants that had not been explicitly programmed into the computer-generated environment. These interactions between participants were usually of greater relevance to collective training than anything an individual simulator station could provide. In gaming terms, player-versus-player interactions became as important as player-versus-environment interactions.

SIMNET was followed by a series of increasingly sophisticated networked simulations and projects. Important moments included The Battle of 73 Easting (1992), a fully 3-D simulation based on SIMNET of a key armoured battle in the Persian Gulf War; the approval of a standard protocol for Distributed Interactive Simulation in 1993; and the U.S. Army’s Synthetic Theater of War demonstration project (1997), a large-scale distributed simulation of a complete theatre battle capable of involving thousands of participants.

The other important source of populated virtual worlds was computer games. Early games such as Spacewar! (1962) and Adventure (c. 1975; see Zork) were played via time-shared computers, then over modems, and eventually on networks. Some were based on multiplayer role-playing in the virtual worlds depicted in the game, such as Mines of Moria (c. 1974) from the University of Illinois’s Project Plato and the original “multiuser dungeon,” or MUD, developed by Richard Bartle and Roy Trubshaw at the University of Essex, England, in 1979, which combined Adventure-like exploration of virtual spaces with social interaction. MUDs were shared environments that supported social interaction and performance as well as competitive play among a community of players, many of whom stayed with the game for years. Hundreds of themed multiplayer MUDs, MOOs (object-oriented MUDs), and bulletin-board-system games, or BBS games, provided persistent virtual spaces through the 1980s and ’90s. By the mid-1990s, advances in networking technology and graphics combined to open the door to graphical MUDs and “massively multiplayer” games, such as Ultima Online, Everquest, and Asheron’s Call, set in virtual worlds populated by thousands of players at a time.

Competitive networked games also provided virtual spaces for interaction between players. In 1993 id Software introduced DOOM, which defined the game genre known as the first-person shooter and established competitive multiplayer gaming as the leading-edge category of games on personal computers. The programming team, led by John Carmack, took advantage of accelerated 3-D graphics hardware to enable rapid movement through an open virtual space as seen from the perspective of each player. DOOM’s fast peer-to-peer networking was perfect for multiplayer gaming, and id’s John Romero devised the “death match” as a mode of fast, violent, and competitive gameplay. The U.S. military also adapted the first-person shooter for training purposes, beginning with a modified version of DOOM, known as Marine Doom, used by the Marine Corps and leading to the adoption of the Unreal game engine for the U.S. Army’s official game, America’s Army (2002), developed by the Modeling, Simulation, and Virtual Environments Institute of the Naval Postgraduate School in Monterey, California. First-person shooters, squad-based tactical games, and real-time strategy games are now routinely developed in parallel military and commercial versions, and these immersive, interactive, real-time training simulations have become a form of mainstream entertainment.

Concerns and challenges

Health and safety

There are many health and safety considerations of virtual reality. A number of unwanted symptoms have been caused by prolonged use of virtual reality, and these may have slowed proliferation of the technology. Most virtual reality systems come with consumer warnings, including: seizures; developmental issues in children; trip-and-fall and collision warnings; discomfort; repetitive stress injury; and interference with medical devices. Some users may experience twitches, seizures or blackouts while using VR headsets, even if they do not have a history of epilepsy and have never had blackouts or seizures before. One in 4,000 people, or .025%, may experience these symptoms. Motion sickness, eyestrain, headaches, and discomfort are the most prevalent short-term adverse effects. In addition, because of the virtual reality headsets' heavy weight, discomfort may be more likely among children. Therefore, children are advised against using VR headsets. Other problems may occur in physical interactions with one's environment. While wearing VR headsets, people quickly lose awareness of their real-world surroundings and may injure themselves by tripping over, or colliding with real-world objects.

VR headsets may regularly cause eye fatigue, as does all screened technology, because people tend to blink less when watching screens, causing their eyes to become more dried out. There have been some concerns about VR headsets contributing to myopia, but although VR headsets sit close to the eyes, they may not necessarily contribute to nearsightedness if the focal length of the image being displayed is sufficiently far away.

Virtual reality sickness (also known as cybersickness) occurs when a person's exposure to a virtual environment causes symptoms that are similar to motion sickness symptoms. Women are significantly more affected than men by headset-induced symptoms, at rates of around 77% and 33% respectively. The most common symptoms are general discomfort, headache, stomach awareness, nausea, vomiting, pallor, sweating, fatigue, drowsiness, disorientation, and apathy. For example, Nintendo's Virtual Boy received much criticism for its negative physical effects, including "dizziness, nausea, and headaches". These motion sickness symptoms are caused by a disconnect between what is being seen and what the rest of the body perceives. When the vestibular system, the body's internal balancing system, does not experience the motion that it expects from visual input through the eyes, the user may experience VR sickness. This can also happen if the VR system does not have a high enough frame rate, or if there is a lag between the body's movement and the onscreen visual reaction to it. Because approximately 25–40% of people experience some kind of VR sickness when using VR machines, companies are actively looking for ways to reduce VR sickness.

Vergence-accommodation conflict (VAC) is one of the main causes of virtual reality sickness.

In January 2022 The Wall Street Journal found that VR usage could lead to physical injuries including leg, hand, arm and shoulder injuries. VR usage has also been tied to incidents that resulted in neck injuries, and death.

Children and teenagers in virtual reality

Children are becoming increasingly aware of VR, with the number in the USA having never heard of it dropping by half from Autumn 2016 (40%) to Spring 2017 (19%).

A 2022 research report by Piper Sandler revealed that only 26% of U.S. teens own a VR device, 5% use it daily, while 48% of teen headset owners "seldom" use it. Of the teens who don't own a VR headset, 9% plan to buy one. 50% of surveyed teens are unsure about the metaverse or don't have any interest, and don't have any plans to purchase a VR headset.

Studies show that young children, compared to adults, may respond cognitively and behaviorally to immersive VR in ways that differ from adults. VR places users directly into the media content, potentially making the experience very vivid and real for children. For example, children of 6–18 years of age reported higher levels of presence and "realness" of a virtual environment compared with adults 19–65 years of age.

Studies on VR consumer behavior or its effect on children and a code of ethical conduct involving underage users are especially needed, given the availability of VR porn and violent content. Related research on violence in video games suggests that exposure to media violence may affect attitudes, behavior, and even self-concept. Self-concept is a key indicator of core attitudes and coping abilities, particularly in adolescents. Early studies conducted on observing versus participating in violent VR games suggest that physiological arousal and aggressive thoughts, but not hostile feelings, are higher for participants than for observers of the virtual reality game.

Experiencing VR by children may further involve simultaneously holding the idea of the virtual world in mind while experiencing the physical world. Excessive usage of immersive technology that has very salient sensory features may compromise children's ability to maintain the rules of the physical world, particularly when wearing a VR headset that blocks out the location of objects in the physical world. Immersive VR can provide users with multisensory experiences that replicate reality or create scenarios that are impossible or dangerous in the physical world. Observations of 10 children experiencing VR for the first time suggested that 8-12-years-old kids were more confident to explore VR content when it was in a familiar situation, e.g. the children enjoyed playing in the kitchen context of Job Simulator, and enjoyed breaking rules by engaging in activities they are not allowed to do in reality, such as setting things on fire.

THE FUTURE OF VIRTUAL REALITY

Virtual Reality is one of the technologies with the highest projected potential for growth. According to the latest forecasts from IDC Research (2018), investment in VR and AR will multiply 21-fold over the next four years, reaching 15.5 billion euros by 2022. In addition, both technologies will be key to companies' digital transformation plans and their spending in this area will exceed that of the consumer sector by 2019. It is, therefore expected that by 2020 over half of the larger European companies will have a VR and RA strategy.

Nowadays, the market is demanding applications that go beyond leisure, tourism or marketing and are more affordable for users. Virtual interfaces also need to be improved to avoid defects such as clipping, which makes certain solid objects appear as though they can be passed through. Or to minimise the effects that VR produces in people, among them motion sickness, which consists of a dizziness induced by the mismatch between the movement of our body and what is being seen in the virtual world.

The big technology companies are already working to develop headsets that do not need cables and that allow images to be seen in HD. They are developing Virtual Reality headsets in 8K and with much more powerful processors. There is even talk that in the next few years they could integrate Artificial Intelligence. The latest 5G standard can also provide very interesting scenarios for the evolution of VR. This standard will allow more devices and large user communities to be connected. In addition, its almost imperceptible latency will make it possible for consumers to receive images in real time, almost as if they were seeing them with their own eyes.

All this means that Virtual Reality is no longer science fiction. It is integrated into our present and, in the coming years, it will lead to advances that will shape the future.