Notes on Cognitive Load, Velocity, and Usability

Understanding the implications of your design decisions from a cognitive science perspective, is essential to being able to design a usable product.

Read more articles on Cognitive Science, Design, Methodology

Cognitive Load

What is cognitive load?

The amount of thinking that is required to digest, understand, and solve a problem is the basics of cognitive load. Reducing the cognitive load and removing friction from an interface translates into a more usable product. However, sometimes controlling the velocity of users through a flow may be what your users need.

A website or application that offers up 100’s of options all at once makes the decision making process, and the extraneous cognitive load, or the way the information is structured and presented, much higher than an application that only shows users options only when they need them.

Presenting fewer options to users makes understanding the options presented and making a decision from those options much faster. This is the theory behind Hicks Law:

in which describes the time it takes for a person to make decisions as a result of the possible choices he or she has.

Hicks Law, Wikipedia Page

Intrinsic Cognitive Load and Interpretation

The intrinsic cognitive load describes the inherent complexity of understanding a particular task. UX practitioners today are starting to understand how to reduce the amount of complexity in their design process to free their brains for the more important task of design thinking. Movements like Lean UX and the use of comics to communicate ideas to others helps reduce misinterpretation of a strategy by simply showing rather than telling.

UX Velocity

Good Friction, Bad Friction

It’s simple. Reduce the amount of friction in an interface’s design, to increase the usability.

This is the bad friction of usability.

The friction that increases the extraneous cognitive load, making us think about “how do I do (Insert your task here)?” The argument to reduce the amount of information and functionality for mobile users of a site or application was a reaction to an understanding of this concept.

However, mobile users need and want to perform the same tasks and access the same amount of information as desktop users, which is why I believe that solution to be lacking the appropriate amount of design thinking to solve the screen size problem and explains my feelings of disappointment when I see the “View full website” links on a major corporation’s mobile site.

Guess what? You’re increasing the bad usability friction when I can’t perform tasks on your mobile site, which was designed to reduce the friction. I would rather zoom in and out on your full website than to be directed to your slim down mobile site.

The Good Stuff

Good usability friction is controlled. Slowing the user down at a point in the flow where you want them to concentrate on the task at hand, or take their time. This can be controlled at a higher flow level, or simply by choosing left aligned, inline form labels to slow down the user through an important form they need to fill out.

Flow velocity is often overlooked when planning out the journey the user will take through a design. Consciously slowing users down, may help the focus the user when performing a complex or important task, like filling out taxes online. Intuit does this very well for their tax software TurboTax, without getting in the users way.