Considering macro cognitive load in user experience design
Cognitive load is the total mental effort being used in the working memory at any given time. In a user experience context cognitive load refers to the mental effort needed to effectively use software including websites and mobile applications. Complex applications with detailed processes, such as those found in enterprise software, typically create an initial cognitive strain that is higher compared to simpler and familiar experiences like online shopping.
As human beings we have finite cognitive capacity. Our brains begin to perform poorly when the amount of information we take in exceeds our ability to process it. Being mindful of cognitive load is perhaps the most important reason to design experiences and interfaces that are simple, uncluttered, and built on existing mental models (or a set of activities believed to be familiar to users).
The good news is that we’re in complete control of what we design. What’s often not considered is the entire digital and physical environment in which our software is used. Our cognitive capacity is constantly taxed by applications, notifications, and other interruptions well beyond our control as designers.
Take for example the environment in which I’m currently drafting this post. I’m using Google docs, a relatively simple and uncluttered interface. But I’ve also got the following competing for my maximum cognitive throughput:
- 10 additional browser tabs
- Notifications from Slack
- Notifications from Messages
- Notifications from Twitter
- Keynote visible behind my browser window
- Team members asking questions and talking to one another
It’s up to me to focus on the task at hand but I’d hardly consider myself an edge case in this scenario.
What does this mean for UX design?
We need to further simplify in cases where the software we design is used in an environment where other applications are likely to compete for attention. Simplification starts well before design and should include:
- A mix of qualitative and quantitative research to determine how the experiences we design can create the highest value with the fewest number of features. This should include field studies to observe actual behaviour, particularly in non-standard environments. Field studies give us insight into the entire environment so we can understand and design for context.
- Validation to ensure our proposed solution isn’t sacrificing value for the sake of simplicity. Iterative usability testing is an excellent way to measure the impact of features and layers of interaction as they’re added. Start simple and make adjustments as necessary.
- Interface design that directs attention to where we know users will find the most value. Interface elements should serve as wayfinding aids that provide a supporting role as users realize value through their experience.
It’s best practice to apply these points to all UX design and product development activities. Their importance is only magnified in environments where cognitive capacity is likely to be strained by applications other than ours. Most websites and web applications are victims of our poor multitasking abilities and should be simplified wherever possible.
The focused nature of mobile applications and the physical limitations of mobile hardware may reduce cognitive load but ever-shaping mental models only amplify the need for simplicity. And the contexts in which mobile applications are used can be loaded with distractions and competing demands on attention.
True experience design needs to consider the macro scenarios and environments in which our interfaces are used. Because the need for our products is often owed to those contexts, and so is the users’ satisfaction with the experiences we create.