The Fulfilment Gap

In 2017, I wrote an impassioned piece on modern UIs after roughly week 1 of the HCI course I took during that semester of my undergrad. In it, I coined the term the ‘fulfilment gap’, which more or less simplified the ideas presented in Don Norman’s The Design of Everyday Things. Here, I’d like to revisit the idea, formalize it, and explore some notable advancements in this area in recent years.

First, the broad idea of a ‘fulfilment gap’ is the distance between a desire and said desire’s reconciliation. This can be applied to almost anything. The set of actions and steps needed for me to ingest a slice of cake is a fulfilment gap where my desire is a slice of cake and the reconciliation of this desire is the satisfaction of my desire for cake. Every action taken from the conception of this desire:

• Deciding what kind of cake I want
• Picking up the cake at the grocery store
• Cutting out a slice
• Grabbing a plate and fork
• Eating the slice of cake

All make up the fulfilment gap. Applying this to the realm of HCI, I present the following precise definition of ‘Fulfilment Gap‘ as this: the set of steps needed to produce a desired result in a piece of technology.

Good UI design often follows the principle of minimizing the fulfilment gap. In my original blog post, my general thought was that it’s impossible to eliminate the gap entirely with current technology. But we’re getting there. The release of devices like the Apple Vision Pro in early 2024 introduced precise gesture controls – almost entirely removing a while dimension of interactions. Brain-computer implants trialed by Neuralink have taken it a step further and created digital pathways from brain directly to machine. It was only a few years after my first post that someone tweeted something with their mind.

And as for how I feel about UIs in 2025, I won’t say they suck! But as a developer there is something a little underwhelming about the state of web design and how everything kind of all looks like same. But stuff, on average, is a lot easier to use than it’s been so at least the gap is closing on that front.