Curiosity is the motivation to know more about something. A main way of affording curiosity is “hint and hide”: users are presented with a bit of information that hints at another, hidden information the user doesn't know yet but finds interesting. Curiosity is a good way of guiding users along a desired path while retaining their sense of autonomy. Rather than blocking off undesired paths or instructing what path to take, good hints form a “bread crumb” users feel they want to follow.
In real time strategy games like Age of Empires II, the player has to defeat the enemy armies by controlling his troops. The map in such games is dark in unexplored areas and hides a lot of resources and vantage points that may prove to be the difference between victory and defeat. This black are denotes unexplored area and the foggy are represents area that are not visible. Players are allowed to feed their curiosity and may or may not be rewarded for their endeavors.
In Viva Piñata: Trouble in Paradise players discover new piñatas by having certain items, landscape types, fruits, and other piñatas in their garden. The player is initially shown this process for a few piñatas, but is then left to their own accord to figure out what other piñatas exist and how to get them. As a result, players become curious and attempt things like filling their garden with snow or planting a bunch of banana trees, among other activities, to see if they can find a new type of piñata.
When designing for curiosity, consider what questions might arise, how the player will react, and the purpose of these questions.
Questions That Arise
This can often be the most difficult part for designers. As someone who knows everything about the game that is being made, it can be very easy to overlook elements that a new player might bring into question. Try describing or showing parts of the game to someone new and see what questions they have. If questions are arising about an element in the game that is supposed to be completely understood, try to make the answer more specific and noticeable. As for adding in more elements of curiosity, this can be easily accomplished by giving the player a specific, simple example of an element within the game. Essentially, you are teaching the player how to learn within the game. You can then include information that hints at the larger picture. This encourages curiosity by showing the player that there is a lot left to be discovered.
The Player's Reaction
Consider what actions the player might take to find the answers to the questions they've encountered. This curiosity should be motivating them to make progress within the game. Players will attempt every kind of solution to find the answer to their questions, and it's important to design around that. Some games, such as Viva Piñata, encourage players to try anything they can think of, and nudge them in the right direction with hints. Other games, such as Machinarium, encourage curiosity towards a single specific solution.
So your player is motivated to make progress, and their curiosity guides them in the right direction. Now it is time to consider what this all means. Make sure that the questions that the players are finding answers to are meaningful within the game, and possibly even outside of the game. As an example, some games provide puzzles with solutions that both relate to the story as well as provide accurate historical information. Regardless of whether the answers are relevant outside of the game or not, it's important that they are relevant within the game. The player should walk away from the solution feeling like their efforts were truly worthwhile.
A simple, step by step process for one basic method of including curiosity in your game:
Currently, no relevant metrics for measuring curiosity in games exist as of yet.
The lens is industry standard and empirically validated.
Schell, Jesse. The Art of Game Design: A Book of Lenses. Burlington: Morgan Kaufmann, 2008. Print.
“Applying Curiosity to Interaction Design: Tell Me Something I Don't Know.” Johnny Holland. N.p., n.d. Web. 20 Apr. 2014.