Laws of Psychology in User Experience Design

Design touches each of us in our very existence on this Earth.

From the physical objects we interact with, to the screens and interfaces begging to be tapped and touched, we are in a new age where there is no shortage of stimuli to keep our brains engaged (or possibly even overwhelmed).

As humans designing digital experiences for other humans, understanding key principles in psychology can help us build a blueprint to create meaningful interactions for others. For me personally, I try to make sure that I remove all biases of my own design preferences, and instead try to understand who I am designing for and what their biggest needs, wants, and desires are for their digital product.

Identifying universal patterns through the study of psychology, we can become better adapted to our own inner design strengths while at the same time designing digital products for the people using the interactions and surfaces we create.

So let’s dive into my top three psychological UX principles every designer should know and apply to their own design work.

Law 1: Hick’s Law

Hick’s Law is based on the principle of how much time it takes to make a decision which increases with the number and complexity of choices. As designers, we need to be aware of finding the right balance between how much to show the user to avoid overwhelming them from too many choices. In a more practical sense, we can see this practice applied in grocery stores like Aldi or Trader Joe’s. When a customer is presented with 50 kinds of canned tomato soup, the sheer amount of options becomes difficult to decipher which one to purchase. However, some stores only have two or three types of soup, and therefore their sales usually increase as the choices are limited. This also makes the decision-making process for the customer more efficient.

In a digital sense, we want to reduce the amount of time it takes for an interaction to be completed. If we place too many buttons, filters, switches, or images in a particular place where the user is weighing their options, information paralysis can set in and the user might deviate away from the website altogether and go elsewhere to purchase a product or find information.

By being aware of Hick’s Law through our design practice, we can ensure that we don’t fall into the trap of designing a tool that is functional, but overwhelms the user with too many options, resulting in valuable time lost through decision making. This is why simplicity always wins.

Key takeaways for Hick’s Law: (source)

1. Minimize choices when response times are critical to increase decision time.
2. Break complex tasks into smaller steps in order to decrease cognitive load.
3. Avoid overwhelming users by highlighting recommended options.
4. Use progressive onboarding to minimize cognitive load for new users.
5. Be careful not to simplify to the point of abstraction. (source)

Law 2: Miller’s Law

Similar to Hick’s Law, Miller’s Law reminds us that the human brain has difficulty remembering more than seven items in working memory at a time.

Translating this law into the practice of interface design, designers need to ensure limited options or asking users to remember information from a previous screen. By displaying relevant information for the user to complete the task at hand, we require less on a users working memory, and instead improve the experience by simply allowing the user to find the information they need to complete the task.

Key takeaways for Miller’s Law: (source)

1. Don’t use the “magical number seven” to justify unnecessary design limitations.
2. Organize content into smaller chunks to help users process, understand, and memorize easily.
3. Remember that short-term memory capacity will vary per individual based on their prior knowledge and situational context.

Law 3: Jakob’s Law

As user’s we are constantly making comparisons between websites. Some websites have easily organized information, a logo in the top right corner, and a menu horizontally displayed across the top left. However, some sites have hidden menus that the user must click to activate the links, or where menus at the bottom of the page follow more of a “non-conventional” design. And while the layout of a website most certainly should incorporate what the aesthetic or topic is about, the user should still be reminded of Jakob’s Law which states that users prefer that a site work the same way as other sites they already are familiar with.

Users spend most of their time on other sites. This means that users prefer your site to work the same way as all the other sites they already know.

Key takeaways for Jakob’s Law: (source)

1. Users will transfer expectations they have built around one familiar product to another that appears similar.
2. By leveraging existing mental models, we can create superior user experiences in which the users can focus on their tasks rather than on learning new models.
3. When making changes, minimize discord by empowering users to continue using a familiar version for a limited time.

As designers, it’s important to take into consideration all the psychological aspects of the users we are designing for, to ensure we do not force them into conforming to a technology but instead design for how people actually are.