Cognitive Load in mobile health applications: design implications

I have been using the British Airways app for a couple of months now and I do really like it. Today, I was trying to check in for an upcoming flight, and deeming myself as an ‘experienced user’ I thought I could do this while half watching tv (on mute) and listening to music. It turns out that I couldnt. I found myself ‘lost’ half way through the check-in process, I saw an OK button, I pressed it believing it wont be associated with a ‘terminal decision’ and I have booked myself the wrong seat (something I am only allowed to change  at the airport). Needless to say, this whole experience left me dissatisfied and somewhat annoyed (at the app and at myself).

This story is the inspiration for this post: ‘cognitive load’.

I have been reading about cognitive load theory and how to design to minimise cognitive strain in online medical health consultations.  How do we ensure that an mobile-based medical consultation (involving a series of health related questions) can support the user? Cognitive strain is correlated to effective decision making, so how can we ensure that the users will make correct choices during a mobile-based medical consultation?

In 1999, Professor Baba Shiv  did a simple experiment on 165 grad students.They asked half to memorize a seven-digit number and the other half to memorize a two-digit number. After completing the memorization task, participants were told the experiment was over, and then offered a snack choice of either chocolate cake or a fruit bowl.

As it turned out, the participants who memorised the 7 digit number were nearly 50% more likely to chose cake over fruit than the other group, which leads to the following conclusion:

‘Willpower and cognitive processing draw from the same pool of resources’

Which is where the problem begins, if both willpower and cognitive tasks use up resources from the same resources pool then this pool is more likely to deplete.  So what about the users? Could the act of making a choice within a multiple choice medical consultation a cognitive drain?  Could this cognitive drain (‘Was that the right choice?’) have an ‘after effect’ to the remaining questions? Is is unconsciously using up resources ?

Nielsen reports that in many of their studies, they have witness that when people have to ‘work hard’ in order to find a piece of information or manipulate a feature, they can become more suspicious, more vigilant, they might start questioning the credibility of your app/content, leading to a potential decrease of confidence and trust.

There are several design guidelines in literature

• Decrease possibility of mistranslation (e.g  unintuitive labels  (accurate, concise, familiar, comprehensive, front-loaded).
• Decrease perceived number of choices (e.g remove redundant links).
• Understand that your users will make mistakes and allow them to recover from them
• Use subtle and appropriate feedback that does not interrupt the flow.
• Test for cognitive strain as part of your design process.
• Do not assume that your product (App/website) is the only think your users are using. Assume a diminished cognitive capacity.

Lets hope I can recover from my mistake and I can finally secure that ‘aisle’ seat for my flight tomorrow.