Time Perception in VR - Making VR

By Stephan Reilly

The ability of players to spend inordinate amounts of time playing games is something that has merited a great deal of criticism since video games have become more commonplace. Players spend upwards of 3 billion hours a week playing games [2010 Jane McGonigal] and lately the mobile game Pokémon Go has become a phenomenon in North America being played by seemingly everyone with a smartphone. Needless to say, people spend a great deal of time playing games. With player’s time being the ultimate resource in games, rather than health or ammunition, it’s important to consider how designers are treating the player’s time. This is a design choice made all the more important when designing for virtual reality, an immersive medium through which a player can get well and truly lost.

There are several ways through which a game can change the player’s perception of time. One of the most obvious and easily executed methods is changing environmental cues like the movement of the sun or moon. Everyone has an internal clock by which their body keeps track of how much time has passed. This circadian clock, as it’s known scientifically, is how the body is able to regulate its processes and behaviours (like tiredness, hunger, etc.) based on the environmental cues of the day-night cycle. Humans have roughly a 24-hour circadian clock. We can tell approximately how much time has passed based on how much the sun has moved above us. With this in mind, there are a couple things designers can do to alter a player’s perception of time.

A recent study conducted by the University of Hamburg found that the position, movement and exposure to the sun can alter one’s perception of time [2016]. They tested 21 students by placing them in three different VR settings: one where the sun moved at normal 24-hour speed, one where the sun moved at double the normal speed and one where the sun didn’t move at all. The study found that those who were in the VR setting where the sun moved at double the normal rate greatly overestimated how long they were in VR for as opposed to the other two groups. With this in mind developers who wanted to extend a VR experience without actually creating more content and requiring the player to wear the headset for long periods of time could simply accelerate the speed of the day/night cycle in their games. Players will feel like they have been playing longer despite having actually played the same amount of time only their perception has changed.

Environmental cues such as the sun are known as “zeitgebers”. They range from light (as demonstrated by the study) to temperature, eating and drinking patterns and much more. Changing any of these can alter a player’s perception of time. When designing a VR game or really any VR experience it is incredibly important to keep zeitgebers in mind. Interestingly the same study that found altering the sun’s speed affected player’s perception of time also found that giving the player more tasks made the perceived time feel shorter. The old expression “time flies when you’re having fun” seems to ring true especially for VR where there is little to no distraction from the fun being had.

Altering zeitgebers in a game can change a player’s perception of time but it should be noted that humans can adapt to new environments or situations over time. This process is known as “neural adaptation” and basically is the process by which humans adapt to new circumstances over prolonged periods of time. For example, if someone moved to a different time zone eventually they would get used to the new 24-hour cycle of sleeping and eating. While the current VR experiences of hours at a time are not enough for this process to occur it’s interesting to note that in the future if VR became used more and more often we could conceivably replace our natural neural tendencies. Eventually, if a person was in a game with an accelerated sun they would adapt over weeks and no longer experience the same time perception discussed earlier.

In summation, a player’s time is the most valuable resource a developer has to consider in their games, before health, ammo or anything else. When developing for VR it is important to consider the player’s perception of time while playing. By utilising zeitgebers to create a shorter play session it can enhance a player’s experience and make for a more enjoyable playtime. As VR becomes used more and more frequently and for longer sessions, it’s crucial that developers keep in mind that neural adaptation can actually alter a player’s natural processes and greatly affect their life, especially in a medium as immersive and engaging as virtual reality.

Sources: IEEE Xplore, Ted Talk: Gaming can make a better world, University of Hamburg Study, Voices of VR Podcast #363

Further Studies:

Time Perception in VR

Long Term Use of Fully-Immersive Technology

Time Perception during Walking in Virtual Environments

Motion Perception During Immersive Walkthroughs