All the best games are easy to learn and difficult to master. They should reward the first quarter and the hundredth.
Bushnell came up with the concept based on his experience with his first game Computer Space in 1971. Its controls were based on four otherwise equivalent-looking buttons but with different functions, and Bushnell found that this had confused players that were trying to learn the game due to their lack of familiarity with these types of controls. Bushnell kept this in mind in designing their future games, such as in Pong and Asteroids, to keep the controls simple and easy to grasp while maintaining a challenging gameplay. The concept is also similar to a philosophy developed by George Parker, the founder of board game publisher Parker Brothers. Parker had said that "Each game must have an exciting, relevant theme and be easy enough for most people to understand. Finally, each game should be so sturdy that it could be played time and again, without wearing out."
- Bogost, Ian (April 2, 2009). "Persuasive Games: Familiarity, Habituation, and Catchiness". Gamasutra. Retrieved 26 February 2014.
- Freeman, Will (April 26, 2016). "Atari co-founder: mobile games make me want to throw my phone". The Guardian. Retrieved September 26, 2021.
- Bogost, Ian (2011). "Chapter 18: Habituation". How to Do Things with Videogames. University of Minnesota Press. pp. 125–133. ISBN 9781452933122.
- "Bushnell's Theorem: Easy to Learn, Difficult to Master". Wolfshead Online. Archived from the original on 26 February 2014. Retrieved 26 February 2014.
- Frank Cifaldi (March 11, 2010). "GDC: Blizzard's Core Game Design Concepts". Gamasutra. Retrieved 26 February 2014.