Transparency in Game UIs

Games are a decent starting point for seeing how mechanical transparency is addressed in computer interfaces since many times simulation games are built around the concept of optimizing some state of the game (resource use, growth, or simply just score etc.) based on decisions the player makes. Here I illustrate how games are approaching some of the facets of mechanical transparency I introduced before.

Specific Why of State. This is a precise explanation for a game element’s attributes including any relationships, the directionality of those relationships, and their valences.

Sim City 4 does this exceedingly well but using a “?” tool which when clicked on an element exposes the state of the attributes of that object relevant to game play. For instance, it will tell you the crime rate and freight trip length for industrial buildings. At any point in the game you get a snapshot of the status of an individual object. Another method used to expose state is by hovering the mouse over an object. This reveals less information than the “?” click, but still shows you “the top three conditions that currently have the most dramatic impact on the desirability of the area” [Sim City 4 manual]. When the state of elements is spatially structured as in a map, overlays are used to show the distribution of a variable across space. Graphs are used to show transparency of state over time, thus aggregations of individual elements’ state are shown as a time series. Sim City 4 manages to achieve a playable simulation in part because the information that is necessary for optimizing the simulation is transparent in the interface. This is done through hovering popups, clickable popups, spatially layered attributes, and temporally graphed attributes.

Another game I looked at, Oil God, adds an additional twist to communicating state transparency by adding an overlay network visual on top of a spatial layout to explicitly show relationships between game elements. Democracy 2 encodes two more variables into its graphical overlays: relationship valence (via red-green coloring) and directionality (via animation direction). Another perhaps simpler method for communicating specific state information is via textual feedback. For instance, in The Garbage Game, where the premise is to keep as much refuse out of landfills, I made a decision in the game to refill and reuse my plastic bottle and it told me: “We figure that a bottle will get refilled about three times on average, so we’ve reduced the volume of water bottle waste in your sorted recycling to 25 percent of the 17,677 tons that New Yorkers currently generate each year, or 4,420 tons.”

Specific Why of State Change. This relates to explicit descriptions of computational state and explanations of why a state has changed. What was the trigger, event, or decision that affected a state change? Was this trigger algorithmic or based on user input? This facet of mechanical transparency is lacking in many of the games I looked at. One game that did have some attempt at an explanation for state change is Energville. At the end of the game, a graph shows the economic, environmental, and security impacts of your decisions. Along the timeline of the graph there are icons of different events that have happened. Clicking on these expands them out with additional textual information. For instance, “2014: wind power fails to deliver. -resulting in a 20% increase in your Wind economic impact.” Since state change is a matter of an attribute over time, annotated graphs and timelines seem to be a natural interface metaphor for explaining state change. Another candidate would be animation. For embedding monikers about state change within an interface itself, something like the afterglow effects in Phosphor might also work.

General Why of State. This is a generic explanation for an element’s attribute or a relationship between attributes, which is not related to the specifics of any particular element.

General why of state involves explication of the existence and valence of a relationship rather than the actual mathematical description, which would be included in the specific why of state. Because the explanation is general in terms of being non-specific, external information and sources can be used to buttress the existence and valence of relationships in the model. One of the tensions that this general information brings up is the granularity of its availability. Is it embedded in the interface or simply available as blocks of text elsewhere? What we see in many games is that the general why of state is offloaded to textual explanation on a separate information page, sometimes also outside of the interactive application itself. In Energyville, which has players managing economic, environmental, and security impacts of energy decisions, each of these facets has explanations in plain text. For instance, the environmental facet, when clicked, lists out all the negative impacts on the environment and cites the names of some recent reports which were used to “inform the impact assessments.”

Sim City 4 and Democracy 2 follow a similar strategy of explaining in text generally what the relationships are between variables of interest. For instance, In Sim City 4, clicking a city opinion poll about land value tells you this: “Represents the average land value in your city. To raise land value place parks, schools, hospitals, and other amenities in your residential zones.” In Democracy 2, the textual information comes in the form of “Encyclopedia” articles, which explain and provide context for the variable currently under consideration. The advantage to a textual approach is that we have well understood conventions for citing information in text. Also, it’s unclear whether or not an abstract relationship could be represented well either in an image or in video material. The value of such multimedia assets may however serve as existence proof for some attribute of interest, if such an attribute is not already obvious.