Solving challenging and complex problems requires the player to apply what she knows in new ways, often synthesizing multiple skills and concepts to forge a unique solution.

Each time she applies a skill or concept in a new way, the player stretches her mental model, making it more flexible and deepening her understanding. She also grows more confident in that particular skill or concept because it was able to cross over and serve her in a new way, making it more likely that she’ll reach for it again in the future.

And each time she uses multiple skills and concepts together, the player is establishing links between those skills and concepts, slowly constructing one unified mental model to supercede several siloed ones. Unified mental models scale better; you can build more on top of them and you will use them more often, increasing your opportunities and willingness to revise them.

Revising a mental model isn’t easy. It takes significant skill and effort, and you will be in a state of temporary confusion as you work things out. If the adage is: “If it ain’t broke, don’t fix it,” then for mental models, it’s often: “If it ain’t completely broke, don’t fix it.” Given how hard it is, it may not be worth the time and effort to revise a mental model that is used infrequently. But revising a mental model that is used all the time can have a huge pay off. And convincing a player to significantly revise and upgrade one mental model can trigger a virtuous cycle because revising one mental model helps you develop the skills to revise mental models in general, lowering the cost of revising other mental models in the future.

Problem-solving in Petri Dish encourages mental model revision because problems and solutions build. A player may settle for a suboptimal solution that happens to work for one problem, but when the next problem amps up the complexity and challenge a little bit more, that suboptimal solution is going to fail. Players are rewarded for proactively building, testing, and revising hypotheses as they go, instead of doing the minimum and waiting. This builds effective habits of mind and pushes players to use higher-order thinking skills, such as analysis, synthesis, and evaluation.