Many serious games that are designed to promote learning, habit formation, or behaviour change
are most effective when played regularly in shorter bursts. This pattern of play is known
as Snacking. However, in the context of serious games,
little has been known about how individual game mechanics support player adherence over
time.
In our previous work, we developed a framework of five game mechanics which encourage sustained
engagement in successful casual games. Namely:
• Rewards: immediate gratifications for the players' actions
• Novelty: providing players with new game elements
• Completion: explicitly assigned tasks, quests, or goals
• Blocking: temporal prohibiting the playing • Waiting: game mechanics that outbreak
the players through the hindrance of their progress or restricted access to resources
Our previous work evaluated the framework using a casual game and showed that these
game mechanics can facilitate player behaviour that is characterized by playing frequently
in short sessions. However, it is unclear how these results translate into the context
of serious games, or into games engaged completely under a player's own volition.
So, in this work, we investigated: How do different Game Mechanics Affect Player
Attrition in a Serious Game?
We designed a field study, where we released six versions of a math learning game for mobile
devices and observed how the participants play over the course of three weeks.
As a testbed for our experiment, we developed a serious game, where we could include snacking
mechanics individually on top of a base game. We designed a simple math learning mobile
game called Infinitus Algebraica. The game shows numbers and operators arranged
in a grid and the goal is to solve as many equations as possible by selecting the corresponding
tiles.
We generated 350 levels in total which become more difficult though the progression.
To provide a ground for the snacking mechanics, we implemented 13 power-ups with an inventory
system and visuals skins as well as background music as rewards.
Base game version For the base game, we disabled the power-ups
and the inventory system. Also, the visual skins, background music, and all levels are
unlocked from the beginning.
Rewards We used a scoring mechanic with power-ups.
Completion We used an achievement system with 48 missions
for Completion. For completing a mission, the players received power-ups, skins, and
music.
Novelty For Novelty, we implemented an (RPG-like)
level-up system with 40 ranks. At milestone levels, the player received skins, music,
and power-ups.
Blocking In Blocking, we restricted the playtime to
10 minutes every 8 hours.
Waiting In Waiting, the power-ups were generated over
time. Every 8 hours the game selected and spawned power-ups. For the remaining time
until regeneration, we displayed a countdown and a notification inside the game.
We first conducted a single-session pre-study on Amazon Mechanical Turk with 50 participants
to evaluate the PX of the game and to validate the comparability between the game versions.
The analysis shows no significant differences in the personality factors or incoming motivation
between the conditions.
To investigate the effect of the game mechanics on adherence, we designed a 3-week behavioural
experiment in which the participants played in uncontrolled conditions. The game was distributed
for mobile platforms Android and iOS.
149 players downloaded the game. 99 of them played Infinitus Algebraica at least once.
The groups were comparable in terms of personality and incoming motivation.
All conditions yield a snacking behaviour with play sessions of around 20 to 30 minutes
and regular breaks of around $1 ½ days.
To investigate how the different conditions affect the player's adherence, we conducted
a survival analysis. The analysis showed that the conditions facilitated
different player behaviours. In Novelty, Waiting and Rewards, the participants played more
intensively in the first days and dropped off quickly.
In contrast Completion and Blocking mechanics facilitated the strongest sustained engagement
over the 3 weeks. Completion yielded by far the longest participation
with the game. While in most other conditions the participants
stopped playing after around 10 days, the participants in the Completion condition engaged
with the game for around 20 to 25 days. Our analysis show that these results cannot
be explained by motivation or differences in performance, but rather that the sustained
engagement can be attributed to the different game mechanics.
In conclusion: The snacking mechanics may facilitate sustained
engagement and can provoke the snacking pattern of play in Serious Games.
The snacking game mechanics are an effective method to design games towards a desired pattern
of play
In the context of Serious Games, meaningful and clear goals are most effective to facilitate
sustained engagement