Functional Fixation and the Power of Parallel Prototyping

Skip navigation

Functional Fixation and the Power of Parallel Prototyping

Functional Fixation and the Power of Parallel Prototyping by Robert Bond

Instead of seeing all possible solutions to the problem, people often zero in on one idea and try to force it through. This phenomenon is called functional fixation and it can prevent us from creating the best solution possible. Fortunately, this type of developer block can be overcome through parallel prototyping.

In this post, I’ll explain why Mendix is the perfect platform for rapid prototyping and therefore is ideally suited to overcoming functional fixation.

What is Functional Fixation?

Let’s consider this theoretical situation, where you have been given the following task and list of materials:

Task: Affix a lit candle to the wall so that no wax drips onto the table below.


  • Candle
  • Box of tacks
  • Book of matches


Image 1: The materials provided

Do you have a solution to this? How about if we remove the tacks from the box:


Image 2: Has the solution become clear now?

All at once, the solution becomes clear: put the candle in the box and attach the box to the wall. Unfortunately, most people don’t see the box as a potential object in its own right. It’s viewed as a container of tacks, not as a candle holder. And this type of rigidity of thinking is what we call ‘Functional Fixation.’

This example showcases that it’s in our human nature to come up with an idea and stick with it, even when it no longer is the optimal choice. As designers, we tend to equate our idea with our intelligence and view any criticisms of the design as criticisms of ourselves. Admitting a design is no longer the best solution is admitting a failure of intellect. As a result, many design processes remain focused on refining an existing solution without considering dramatic alternatives. This one-track approach is known as Serial Design.

Even in Mendix, we frequently encounter this phenomenon.  We start up a new user story, think for a few minutes, conceive a brilliant idea to implement business functionality, and then start throwing together our Microflows. And sometimes, we hit a wall where our idea doesn’t quite work. This could happen for many reasons, maybe the users don’t like the experience, for example. Not wanting to abandon the idea, we often try to pack additional functionality into the existing solution. With this in mind, how can developers avoid falling into the trap of functional fixation and serial design?

Parallel Prototyping

Parallel prototyping means deliberately starting the design process with multiple competing ideas. As you go along, you evaluate the success of your ideas and whittle away solutions that underperform. In the end, your remaining solution is the best solution.

In the paper, Parallel Prototyping Leads to Better Design Results, More Divergence, and Increased Self-Effcacy,Dow et al. looked critically at the power of this method. In this study, teams designed advertisements either using parallel or serial design methods. Teams received feedback after each round of iteration and used website clicks to evaluate effectiveness. In the end, the parallel design produced >15% higher click rate.

With this study in mind, we see that you need to consider multiple approaches to ensure the best possible design. Fortunately the Mendix platform allows you to do just that!

Parallel Prototyping in the Mendix Platform

A rapid application development platform is ideally suited to parallel prototyping. Due to the speed at which designers can create pages and Microflows, it’s much easier to build multiple solutions for a single problem.

Consider another example:

Your users wanted a system to generate a request for assistance. But since this was a new idea for the group, no framework existed to copy. Some users thought that the system should collect minimal  information to speed the request process. Others felt that increasing the detail on a request would speed up the time it took to complete the request. Thanks to Mendix, I was able to create these two options through prototypes and run through the process with the users.

In the end, the business agreed on a hybrid of the two models that took the best of both designs. That solution would never have made itself apparent without actually building both processes in Mendix!

So if you find yourself stuck in serialized thinking, consider parallel prototyping to broaden your design horizon. Mendix is one of the few software tools that provides the speed required, so take advantage!

Happy Modeling!

Author Info

Robert Bond