Why we do research: UX principles and design trade-offs

By David

In The Psychologist’s View of UX Design, Susan Weinschenk writes about extrapolating user experience principles from research and psychology. We get users into our lab almost every week for usability testing and research, and usually clients drop in to observe the tests too. It is my favourite part of doing UX – its like brain gym – analysing what happens in the lab always sparks interesting debate and new insights.

On the back of our research we extrapolate user experience principles that guide our design thinking on projects that have similar challenges. I’m happy to see lots of overlaps between our, and the principles in Susan’s article. So quoting from Susan’s list, here are seven principles that I have been thinking about lately.

Surfacing information

It is better to show people a little bit of information and let them choose if they want more details. The fancy term for this is progressive disclosure.

We know that people are reluctant to read detailed information on a screen. Rather than show all the information upfront, or on lengthy FAQ pages, an alternative is to surface snippets of information where users need it, providing links to more detailed information.


Provide defaults. Defaults let people do less work to get the job done.

A lot is being written about defaults, besides helping users do less, it is also a tool that can be used when designing for behaviour change. It links to the idea of libertarian paternalism which ‘tries to influence choices in a way that will make choosers better off, as judged by themselves’.


People can’t multi-task. The research is very clear on this, so don’t expect them to.

An example of multi-tasking is asking users to collect paper documents, scan or photograph them, followed by uploading or emailing them. This sounds easy enough? Not so. Unless the process is super simple, most people will simply not do it, or postpone it indefinitely.


Assume people will make mistakes. Anticipate what they will be and try to prevent them.

In situations where users are likely to make errors, look for ways to shift the user’s burden onto the system. A classic example of this is when a user has to upload a file, asking them to identify the file format will cause many to fail the task. Don’t ask them, do it for them.


People can only remember about 3-4 items at a time. The 7 plus or minus 2 rule is an urban legend. Research shows the real number is 3-4.

Don’t expect users to remember information from one step to the next. Our research shows that breaking complex tasks down into a series of simple steps may fail to help users get something done, because people struggle to remember what they did in a previous step when its no longer in front of them.


Research shows that if you want people to fill out a form, give them something they want and then ask for them to fill out the form, not vice versa.

Filling out forms is something most users would rather not do. Many users will move on if you ask them to register before they are convinced that your product is useful to them. In Mobile Usability Jakob Nielsen and Raluca Budiu cautions against early registration:

Since 1999 a key usability guideline for e-commerce shopping cart and checkout processes has been to allow users to buy without having to register. Sites that allow ‘guest checkout’ have much higher conversion rates than site that require users to make up a user ID and password before they’re permitted the rare privilege of forking out their money.

Mental models

In order to create a positive UX, you can either match the conceptual model of your product or website to the users’ mental model, or you can figure out how to ‘teach’ the users to have a different mental model.

Understanding users’ mental models is ultimately why we do research. But understanding our own mental models as designers, and those of the stakeholders we design for, is equally important when we tackle wicked problems – projects where our designs need to fit both the mental models of users, and those of stakeholders in complex organisations.

User experience principles don’t provide answers to usability questions, and they don’t make our jobs easier by applying the same set of rules to all situations. Nielsen and Budiu sum it up nicely:

Usability questions seldom have a single answer. Rather, they are qualitative issues that specify the direction and nature of inevitable design trade-offs.

We find out what the design trade-offs are by doing research.