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The Effect of Animation on Game Usability

5.8.2012

I wrote my Master of Science thesis on the effect animation might have on usability of digital games. I promised to my research subjects (I like to call the subjects, yeah) I'd write a small summary of the research findings and statistics of the questionnaire used in the study, so here goes. I have removed most of the boring theory from this summary. If you're interested in it and you understand Finnish, feel free to download the full pdf from the bottom of the page.

Why Animation?

The main reason for researching the effect of animation on game usability is simply that animation is a very natural way for us humans to read information. Since human visual system is made for observing moving images (yes, the world around you), animation provides a very natural way to represent that information. You don't need to learn how to decode that information, like in the case of street signs. Everyone can understand animation!

Another good reason for taking advantage of animation is that it's constantly present in (modern) games: in player characters, in monsters, environment, everywhere. Since you already have animation in your game, why not use it to make the game more usable? Now, I'm not saying that animation should no be used purely for entertainment or artistic purposes, but it's important to be aware of your options. Plus of course animation is way more interesting than plain text, which adds to immersion and simply makes the game more fun.

The thesis' purpose was to build some sort of basic model of animation's possible usability effect. It can be used by game designers and artists as a source of inspiration or a sort of heuristics style "checklist" during the development process.

About Game Usability

The concept of usability in games is kind of a paradox: a game that is extremely usable would be an awful game ("Press A to complete game"). Game designers create obstacles and problems into the player's way, deliberately decreasing its usability. Usability in sense of game design must be viewed from an angle different from the traditional efficiency oriented software development. One typical weirdness is that in games the players are expected to make mistakes - a game without mistakes would be a game without a challenge, which would be rather boring.

When working on game usability, one should always consider the purpose of the game and direct usability testing in a way that supports that purpose. In most cases it means directing usability testing to those areas that require very little thinking, such as controls, map views or game status in general. That way the player may concentrate on playing the game rather than having to constantly ponder how to play the game. On the other hand, if the purpose of the game is to be a realistic simulator, simplifying controls would work against the game design purpose, even tho it increases usability. To put it short, you have to put game design before usability.

How to Use Animation

So, in which ways does animation possibly improve game usability? I divided possible uses for animation into three main categories, as proposed by Chuck Clanton back in '98. The categories are:

  • User Interface
  • Game Mechanics
  • Gameplay

All the proposed usages and their summaries are listed in a table below (well, a couple of scrolls below).

1. User Interface

User interface is the visible part of game status information, typically displaying score, health, progress... you know, the boring but vital stuff. Animation can be used here very much in the same fashion as with desktop applications: to display that information more effectively. This can be done by saving screen space by using temporal dimension (like with weather forecasts that show simulation of the next 24 hours) or by reducing cognitive load, so that the player doesn't have to decode the symbols used in the game. A basic example would be using an object that moves from left to right rather than displaying an icon that has a running man or an arrow that points to right.

The interesting part, tho, is using animation to enhance immersion by placing UI elements inside the game world itself. Animation often fits to game worlds better than text and numbers, making it more natural and less intrusive way to display user interface elements.

2. Game Mechanics

Game mechanics includes all the things the player sees happening inside the game world, be it jumping, running, fighting or movement of a car. This part is where animation has most of its potential, as most of the game mechanics have to be animated anyway. It's just a matter of doing it so that it carries the right message. Animation can be for example used to display game state or affordance, give feedback, demonstrate game events - all very traditional concepts in usability. Also, as mentioned before, animation is very easy to "understand", which increases its usefulness even more.

One of the biggest hitters is displaying game state and affordance. Animation can be used to display varied information in the game world in a fashion that is easy to interpret and doesn't break immersion. Say, your character has a knee injury and can't run. Instead of displaying a red cross icon on his leg and some sort of textual note about decreased speed, you could just make the character limp and stumble when the player selects the action for running. In the same manner animation display affordance, or the lack of it, by hinting certain actions are possible or not available. In the case of the limping character, jumping for instance, does not seem possible. One good example of using animation to display causality is Prince of Persia game, in which sloped platforms have sand constantly falling off them. The falling sand confirms that the platform actually is sloped, and also hints that the player might fall off from it, should he try jumping on it.

Human senses have evolved into detecting moving objects. Noticing a running rabbit in the middle of a forest or an attacking lion at the corner of your eye could be a matter of life and death back in the old days. Detection of movement happens in very early level of the human visual system, making it immediate and economic from cognitive point of view. For this reason animation, or any sort of moving images, is very useful for drawing user's attention, especially in peripheral vision.

3. Gameplay

Gameplay is the deep stuff of games. The stuff that makes the game interesting and in general makes the game a... game. While gameplay has no straightforward usability effect, it is extremely important for the user experience of the game, playing its own part in the strange game usability concept.

The most obvious use for animation here is pure entertainment. Animation is in general perceived much more entertaining than text or still images. Animation can also be used to motivate the player and it isn't unusual to find small rewarding animations in games. The Sims serie for instance has lots of small animations used a rewarding. The interesting part in Sims' use of animation is that the animation rewards are used also for negative effects, which further encourages the player to experiment with the game and toy around with its functions. Finally, animation may be used to create an emotive response in the player. While this is of course way more harder than simply adding some animation, games are often played for their emotive effect and animation offers a natural way to communicate the desired message.

Proposed Usage Explanation Example
1. User Interface
Make user interface more natural Use animation instead of text or icons. Place ammo counter in HUD or into character's equipment, such as arrows in quiver.
Save space Animate one space rather than displaying multiple spaces with different view. Rotating view of a car from different angles to display damaged components.
Decrease cognitive load Use animation to make the user "think less", enabling them to concentrate on the game rather than its interface. Animate golf ball hit preview with ball's speed and direction rather than displaying force vector (arrow).
2. Game Mechanics
Visualize game state Display game state as in-game animated format rather than in user interface. Visualize player health using player character's movement. Badly hurt characters should pant, holding their wounder shoulder while keeping their head down.
Visualize AI actors Animate non-player characters in a way that represents their motives and makes it possible for the player to understand what they are about to do. Make AI character look at an object before grasping it. Make dangerous characters act in an aggressive manner (even when they haven't yet noticed the player).
Demonstration Demonstrate an action by showing another character doing it instead of showing textual explanation. Show enemies using traps to hunt food, so that the player might try to use the same traps as a weapon.
Feedback Use animation to give the player feedback for a successful (or unsuccessful) action. Have a sword bounce off an armored opponent to show the weapon is ineffective. If certain weapon is especially effective against a monster (like fire against giant spiders) make the hits look like they really hurt!
Affordance Make actions to see possible (or impossible) using gentle hints. If water seems to be boiling, the player won't probably try to jump into it. On the other hand, if the water shimmers and has some gently waves, it encourages the player to try swimming.
Gain user's attention Use movement to catch the player's eye. Direct player's attention by making characters turn their eyes into objects. Making something glow is a classic way to tell something is important
Prediction and causality Animate things in a way that makes it possible to predict the animation's outcome. If an enemy is about to do a powerful punch, make it move its fist backwards first. In general, the larger the movement, the longer the preparation time is.
Natural game mechanics Make game actions seem believable. Increase immersion by adding non-repeating random movement to character animations. Don't just pull the character up after the jump button is pressed. Jumping requires using muscles to fight the gravity, so make the player character gather his strength by kneeling down a bit first. If it seems like such things as gravity and muscles actually exist in the game world, it feels a lot more believable.
3. Gameplay
Entertainment Create more lively worlds with beautiful animation. Add animated objects (flowers, birds, animals) to still scenery.
Motivate Use animation as reward and encourage different playing styles with animation hints/rewards. Make a mini boss die in some cool way or add special animation to power attacks.
Communicate invisible concepts Use animation to visualize concepts that are otherwise hard to communicate without textual message. Use floating objects to show the direction and strength of gravity inside a space station.
Create an emotive response Games are usually played for their emotive effects. Use animation as a tool to empower that effect. Use slow and fading (background) movement to create a distressing or sad atmosphere. Use fast movement for a more cheerful scene.

Taking It to Practise

To see if the theory summarised above has anything to do with practise, I made a small game that tests the theory. Players played (randomly) either an animated or non-animated version of the game (50/50 share) and were asked to answer certain questions regarding the game and its usability. The game also recorded some in-game data, such as final score and the first occurence of damage. The total amount of people participating in the study was 470. Most of the research subjects were 15 to 35 years old and played digital games almost daily. Only 10% of the subjects were female, probably because the research was advertised in internet game forums that often tend to have hardcore male gamers.

The game is a side scrolling 2D game in which the player is controlling a bicycle'o'copter. The player may move left and right, tho the main gameplay comes from having to control the amount of power put into the copter - too much power makes the player hit the "ceiling" while too little lift takes the copter to ground.

Play the game here (no research data is saved).

Results

Six different aspects of game usability were measured

  • VIS - Visual appeal of the game
  • CONT - Player control's learnability
  • NAT - Naturality of player movement
  • DET - The easiness to determinate whether an object was harmful or helpful (enemies/bonuses)
  • STAT - Awareness of game status (health, speed etc.)
  • ENT - Entertainment value of the game in general

I'll skip the numeric details, as the goal of the research never was to have any "mathematical proof" for the theory. The research shows that the animated version did better in all measured variables. Animation especially made player movement feel more natural and, less surprisingly, in general increased the visual appeal of the game. Animation also made the game more entertaining. The players of the animated version also had their first collision (hitting ceiling or ground) approximately 38% (~5 seconds) later, suggesting that animation helped the players to get a grip of the game idea during its first second.

Interestingly, the subjects who were less experienced with games in general scored a lot higher point in the game while playing the animated version. On the other hand, hardcore players playing the animated version had slightly lower score than those who played the non-animated version. This might imply that animation is especially effective for less experienced players who aren't as familiar with games and controls in general. On the other hand hardcore female players scored 50% higher using the animated version, which might suggest possible differences between sexes. The amount of female players was rather low, so this would need more research, tho.

Summary

The research suggests following findings:

  • Animation in general truly can increase game usability
  • Animated games are perceived to be entertaining and visually pleasing
  • Animation can effectively teach basic controls and visualize game state
  • Less experienced players gain special benefits from the use of animation

Thanks for reading! Should you have any comments, feel free to drop me a note to markus@heiolenmarkus.com.

Get full pdf here (900kB, 64 pages, Finnish)

Play the game
You can still play the game, but no research data will be saved.

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