The group of researchers from Aalto University in Finland gathered volunteer gamers and asked them to tap away. Some users were given physical keys, others used touchscreen. The results showed a marked difference in timing.
Professor Antti Oulasvirta, one of the study authors said, “We can finally explain why games that require accurate timing are annoyingly hard on touchscreens.” The three major factors involve our basic physical limitations, predictability, and processing time.
First, people using a touchscreen can’t keep their finger hovering indefinitely at a constant distance from the screen. Even the slightest tremor or breath alters the distance between the finger and the screen, which therefore changes the time required to react to on-screen stimuli. By comparison, when using a keyboard or button, a player’s finger generally rests on the button. There is no variability in contact related to the distance from finger to activator (screen or button).
Next, the predictability issue arises after a player has tapped the touchscreen and is wondering if the game will react. The human neural system has a hard time predicting if the input event (tap or touch) registered in-game. Software detects and reacts to the touchscreen, but we don’t know instinctively how long that reaction will take. We can’t sense it, so it’s not predictable.
Last, after the input has been registered, the game still needs time to process it. That time varies based on a host of factors (when you want to throw your phone at the wall because some background process is making everything run slowly is the most extreme and rare case).
This research implies that making touch events more predictable will improve gamer’s performance, and therefore make a game or any touchscreen program seem less annoying. If the event is registered when the finger has reached the maximum surface contact area, people can improve their timing. What this means is designers may have to take a really close look at how devices or apps respond to touch and make some adjustments for feedback or response.
But this isn’t much of a surprise. Most gamers have already accepted what this research just proved: touchscreens today will never be as accurate for what we could describe as basic gaming inputs (press X to open that door) as physical keys. The problem with the variability of finger travel distance, an unpredictability that will make a given game harder on a touchscreen than on console or PC, won’t be solved until players can rest their fingers on a touchscreen during gameplay.
Of course, timing-based games will remain huge draws on touchscreen platforms. A game’s challenge is often part of its appeal, and this will likely continue even now that its been made clear you need hands as steady as a surgeon to beat some games. As well as our desire to challenge ourselves, this by no means applies to all touchscreen games, some of which require no timing whatsoever.
In any case, this research should serve game designers well. According to the experiment with Flappy Bird, “the model could predict how often gamers die,” so at least designers can put an accurate number on their brutality.
The paper on the subject titled “Modeling Error Rates in Temporal Pointing” will be presented at the CHI (pronounced Kai) 2016 conference, taking place May 7 -12 in Silicon Valley.
