As user experience (UX) practitioners, we use studies and principles from psychology, social psychology, and human computer interaction to help understand why users think and act the way they do. If we understand the why, then we can predict how they will interact with our interfaces in the future.

While there are many principles that can be applied to UX, three that I find particularly useful in our line of work include:

  1. The Hick-Hyman Law
  2. Principle of Least Effort
  3. Fitts’s Law

1. The Hick-Hyman Law

The more options, the better, right? The Hick-Hyman Law, also commonly referred to as Hick’s Law, says the more options, the longer. The Hick-Hyman Law predicts that the time it takes a user to make a decision is increased by the number of choices that user has.

In other words, the more options you have, the longer it will take you to make a decision. Let’s look at a practical example. Here’s an example from a Zion & Zion client’s old homepage. We ran a click test asking 30 participants where they would click to sign up for an upcoming fitness class.

The results form our click test are below:

Old Sun Health Homepage Example | 3 Human Interaction Principles to Apply to UX

As you can see, the results varied dramatically. That’s because there are more than 25 items (29, if you include the social icons) before you even begin scrolling.

Now, look at the homepage design for the new site that we developed for them. We ran the same click test with 30 participants, and the results are below:

New Sun Health Homepage Example | 3 Human Interaction Principles to Apply to UX

The second test took users significantly less time to make a decision. The time it takes users to make their decision was significantly shorter in part because of the reduced number of choices they had. That’s the Hick-Hyman Law.

In UX, you want your users to find the information they are looking for as fast as possible. So, do yourself a favor and remember the Hick-Hyman Law next time you’re tempted to give your users as many options as possible.

2. Principle of Least Effort

This is a simple principle, but also a very valuable one. The principle states that when there are several ways to achieve the same goal, we will choose the course that requires the least amount of effort.

Or in other words, we’re all lazy. As UX practitioners, we should take this into consideration when designing interfaces. Our goal for every website is to allow the user to accomplish their task in the easiest way possible.

Here’s a simple example. We built the new website for Salons by JC. In our research, we found that users coming to the website fell into three distinct user groups: salon professionals, salon customers, and salon franchisees. Each of these user groups had very distinct goals. To ensure each user group achieves their goal, we used insights from our research to structure the information architecture of the new website. As seen in the example below, the website’s navigation and callouts below the homepage masthead image were distinctly created for each unique user group.

Salons by JC Homepage Example | 3 Human Interaction Principles to Apply to UX

Although this may seem straight-forward, there are countless websites out there that don’t put their users’ needs first. If a user can’t find what they want on your website, they are going to move on to your competitor’s site who does put their needs first—taking the path of the least effort.

3. Fitt’s Law

Last but not least, Fitts’s Law. Fitts’s Law states the time it takes to move to a target can be calculated by the distance to the target and the size of the target. In other words, the farther away and the smaller the target is, the longer it will take the user to get to the target.

Let’s look at a real example. One wireframing tool we use at Zion & Zion is Mockflow. Mockflow is an online wireframing tool that allows you to quickly build low-fidelity prototypes, share the link with others, and collaborate. We love Mockflow, but there’s one element of the software that could be improved by referring to Fitts’s Law.

In the screenshot below, I’m editing the button elements toward the bottom of the page. Once I’m done editing the buttons, what do I need to do?

Old Wireframe Example | 3 Human Interaction Principles to Apply to UX

I need to go up to the top right of the screen to hit “Save Changes.” This may seem like an easy task, but when I’m quickly wireframing, I have to carefully move my mouse all the way up away from where I’m working to save my changes and continue wireframing. Not only is the button far away from what I’m editing, but it isn’t very large either. It’s pretty frustrating.

I did a quick mockup of how this experience could be improved using Fitts’s Law. It’s such a small adjustment but would save me time as I’m wireframing.

New Wireframe Example | 3 Human Interaction Principles to Apply to UX

You can see that by putting the “Save Changes” close to what I’m actually editing, it would take me less time to save my changes. Since MockFlow is a software I use in my day to day role at Zion & Zion, I know that a simple change like this would save me a lot of time and give me a better user experience, all thanks to Fitts’s Law.

Putting It Into Action

By using these tried-and-true principles, you can ensure a better experience for your users and more success for both you and your company.

In addition to these psychology principles, there are many tools available for UX practitioners. A recent Zion & Zion article reviews our favorite tools for user experience testing and design, so you can consider every aspect of user experience, from wireframing and research, through development and post-launch refinement.