Game designers have been designing for digital behavior change for longer than just about anyone. They design the environment that the users interact with and the rules through which all of the user's actions are interpreted. The goal of game design is to influence user behavior to create an intended experience. They are doing Behavioral Product Strategy.
As such, game designers are asking many of the same questions as applied behavioral scientists.
How do we design meaningful choices? A friend of mine named Javier Velasquez once told me: “Behavioral economics sets up a choice architecture so that people are most likely to pick one specific option. Game designers aim to give users meaningful choices where all of the options are equally valuable, they just represent different play styles that suit each player. There’s a balance there if you want to create engagement in product design.”How do we design the choices that people make so they are more likely to make choices that are in their best interests? How can we design their choices so people reveal their true preferences?
How do we recognize the goals that users have and design the product so they are likely to succeed? How do we recognize users when they are successful, track their progress, and return this information to them in ways that shape their behavior? How can we intelligently deliver feedback to the user in the form of data visualization to motivate the user to aim higher?
People are often going to fail when they attempt to achieve their goals. How do we Intentionally design for failure states so people try again instead of giving up? How do we increase the likelihood that they are successful when they try again?
How do we design for Difficulty Matching so the users don't get bored or frustrated from the tasks they are being asked to do? How do we build people's capabilities so they are able to overcome challenges they inevitably face, over the course of their whole experience?
How do we account for individual differences between users in skill level, goals, and playstyles so our target users gain value?
Questions can be answered through methods beyond experimentation. If millions of good games exist that are attempting to answer similar questions to behavioral scientists through their design decisions, then that just means they are using different methods to learn about people than behavioral scientists.