The Law of Conservation of Complexity (Tesler’s Law)

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Image created with Midjourney. Image prompt: 2d illustration, minimal style of An engineer at a desk with a large, complex machine on one side and a streamlined, simple machine on the other. Users are interacting with the simpler machine, but are seen tackling more complex tasks

The development of digital products is a delicate balance of functionality and usability. Designers and developers strive to create solutions that are feature-rich yet user-friendly. One concept that offers valuable guidance in this endeavor is Tesler's Law, also known as The Law of Conservation of Complexity.

What is Tesler's Law?

Developed by Larry Tesler, a computer scientist who spent significant time working for Xerox PARC and Apple, Tesler's Law asserts that for any system, there is a certain amount of complexity which cannot be reduced. The idea is that complexity is conserved and can be shifted around but never eliminated.

While working on user interfaces, Tesler realized that the ease of interaction with an application was just as crucial as the application's functionality itself. He advocated for developers to invest extra effort in reducing application complexity rather than burdening users with it1.

Tesler's Law in Digital Product Examples

Email Clients

Consider the example of an email client. To make it easier for the end user, an email client might hide the complexities of protocols like SMTP and IMAP. Users don't need to understand these protocols to send or receive emails. The complexity is absorbed by the application, making it more user-friendly.

Graphic Design Software

In the realm of graphic design, applications like Adobe Photoshop have a high degree of complexity to provide powerful functionality. However, for users who need to perform simpler tasks, Adobe offers more user-friendly applications like Adobe Spark, which hides much of Photoshop's complexity.

E-Commerce Platforms

E-commerce platforms like Shopify provide business owners with the ability to set up an online store without needing to understand the complexities of web development, payment gateways, and security protocols. The platform handles the complexities, allowing the user to focus on running their business.

Implications for Digital Product Development

Understanding Tesler's Law can significantly inform the development of digital products.

User-Centric Design

The principle underscores the importance of a user-centric approach to design. By absorbing the complexity, we can create products that are easier for users to interact with, thereby improving the overall user experience.

Balancing Complexity

Tesler's Law is not an argument for oversimplification. If an application is too simple, it might not provide the functionality users need. Instead, it's about finding the right balance - reducing unnecessary complexity while ensuring users can still complete their desired tasks.

Encouraging Advanced Use

Interestingly, when applications become simpler, users tend to attempt more complex tasks, as suggested by user experience expert Bruce Tognazzini. This can lead to users discovering and using more advanced features, increasing their engagement with the product.

In conclusion, Tesler's Law is a powerful principle that highlights the importance of managing complexity in digital product development. By understanding and applying this law, we can create digital products that not only meet user needs but also provide a satisfying and efficient user experience.

Another take on the topic

Bruce Tognazzini's take on Tesler's Law centers on the idea that the complexity of a task can't be eliminated, but rather, it can only be shifted. He introduces what he calls the "Law of Commuting," which states that "The time of a commute is fixed. Only the distance is variable." This means that people will aim to experience an equal or increasing level of complexity in their lives, regardless of any efforts to reduce it. If the complexity people experience in a specific task is reduced, they will pursue more challenging tasks to maintain the same level of complexity.

Further, Tognazzini suggests that as we continue to reduce the proportion of complexity of any given function that we expose to the user, we can expect the difficulty and complexity of our own tasks, whether at the application or OS level, to increase over time. This has been the case so far, with technology transitioning from simple tools like memo writers and sketchpads to more complex applications like document processors and Photoshop1.

Bruce "Tog" Tognazzini is a prominent figure in the field of human-computer interaction and usability. He is a founding member of the Nielsen Norman Group, a leading firm in user experience, and served as an Apple employee in the early days, where he established the Apple Human Interface Group. Tognazzini has written several books on interface design, and his insights have shaped the principles of user-centric design in software development.