Laws of UX, 2nd Edition

Chapter 4. Hick’s Law

The time it takes to make a decision increases with the number and complexity of choices available.

Key Takeaways

• Minimize choices when response times are critical to decrease decision time.

• Break complex tasks into smaller steps in order to decrease mental effort.

• Avoid overwhelming users by highlighting recommended options.

• Be careful not to simplify to the point of abstraction.

Overview

One of the primary functions we have as designers is to synthesize information and present it in a way that doesn’t overwhelm the people who use the products and services we design. We do this because we understand, almost instinctively, that redundancy and excessiveness create confusion. This confusion is problematic when it comes to creating products and services that feel intuitive. Instead we should enable people to quickly and easily accomplish their goals. We risk causing confusion when we don’t completely understand the goals and constraints of the people using the product or service. Ultimately, our objective is to understand what the user seeks to accomplish so that we can reduce or eliminate anything that doesn’t contribute to them successfully achieving their goal(s). We, in essence, strive to simplify complexity through efficiency and elegance.

What is neither efficient nor elegant is when an interface provides too many options. This is a clear indication that those who created the product or service do not entirely understand the needs of the user. Complexity extends beyond just the user interface; it can be applied to processes as well. The absence of a distinctive and clear call to action, unclear information architecture, unnecessary steps, too many choices or too much information—all of these can be obstacles to users seeking to perform a specific task.

This observation directly relates to Hick’s law, which predicts that the time it takes to make a decision increases with the number and complexity of choices available. Not only is this principle fundamental to decision making, but it’s also critical to how people perceive and process the user interfaces we create. We’ll look at some examples of how this principle relates to design, but first let’s look at its origins.

Origins

Hick’s law was formulated in 1952 by psychologists William Edmund Hick and Ray Hyman, who were examining the relationship between the number of stimuli present and an individual’s reaction time to any given stimulus. What they found was that increasing the number of choices available logarithmically increases decision time. In other words, people take longer to make a decision when given more options to choose from. It turns out there is an actual formula to represent this relationship: RT = a + b log2 (n) (Figure 4-1). This formula calculates response time (RT) based on the number of stimuli present (n) and two arbitrary measurable constants that depend on the task (a, b).

Fortunately, we don’t need to understand the math behind this formula to grasp what it means. The concept is straightforward when applied to design: the time it takes for users to interact with an interface directly correlates to the number of options available to interact with. This implies that complex or busy interfaces result in longer decision times for users, because the users must first process the options that are available to them and then choose which is most relevant in relation to their goal. When an interface is too busy, actions are unclear or difficult to identify, and critical information is hard to find, the mental effort required to find what we are looking for increases. This increase in mental effort is commonly referred to as cognitive load, which we covered in Chapter 3, “Miller’s Law”.

Figure 4-1. Diagram representing Hick’s law

Psychology Concepts Paradox of Choice

Have you ever noticed it’s easy to get indecisive and overwhelmed with the more choices you have? Take, for example, a restaurant menu with a plethora of food and beverage options. This menu will inherently require more mental energy to process and decide on an option in comparison to a menu that’s focused around a dozen or so items. Despite the common assumption that the more choice we have the better, the opposite is often true: more choice leads to choice overload.¹

This is the paradox of choice: the range of choices that is available today for virtually anything is far greater than in the past, but still, people are not happier.² The paradox was popularized by American psychologist Barry Schwartz and relates the ideas of psychologist Herbert A. Simon from the 1950s to the psychological stress that most consumers face today.

Schwartz was inspired by a study conducted by psychologists Sheena Iyengar and Mark Lepper in 2000 that challenged the implicit assumption that having more choices is necessarily more intrinsically motivating than having fewer.³ In the experiment, shoppers at an upscale food market were presented with a display table showcasing 24 varieties of gourmet jam. Those who sampled the different spreads received a coupon offering a small discount on any jam purchase. On another day, shoppers encountered a similar table, but this time only six varieties of jam were on display. The larger display captured more attention compared to the smaller one. However, when it came time to make a purchase, individuals who saw the larger display were only one-tenth as likely to buy compared to those who saw the smaller display. In other words, shoppers were more likely to make a purchase when presented with a limited choice of gourmet jams compared to a larger selection.

Examples

Now that we have an understanding of Hick’s law, let’s take a look at some examples that demonstrate this principle. There are examples of Hick’s law in action everywhere, but we’ll start with a common one: remote controls.

As the number of features available in TVs increased over the decades, so did the options available on their corresponding remotes. Eventually, we ended up with remotes so complex that using them required either muscle memory from repeated use or a significant amount of mental processing. This led to the phenomenon known as “grandparent-friendly remotes.” By taping off everything except for the essential buttons, grandkids were able to improve the usability of remotes for their loved ones, and they also did us all the favor of sharing the modified remotes online (Figure 4-2).

In contrast, today we have smart TV remotes: the streamlined cousins of the previous examples, with the controls simplified to only those that are absolutely necessary (Figure 4-3). The result is a remote that doesn’t require a substantial amount of mental energy. The complexity is transferred to the TV interface itself, where information can be effectively organized and progressively disclosed within menus.

Figure 4-2. Modified TV remotes that simplify the “interface” (sources: Sam Weller via Twitter, 2015 [left]; Luke Hannon via Twitter, 2016 [right])

Figure 4-3. A smart TV remote, which simplifies the controls to only those absolutely necessary (source: Apple, 2023)

Now that we’ve looked at some examples of Hick’s law at work in the physical world, let’s shift our focus to the digital. As we’ve seen already, the number of choices available can have a direct impact on the time it takes to make a decision. We can ensure better user experiences by providing the right choices at the right time rather than presenting all the possible choices all the time. An excellent example of this can be found with Google Search, which provides the varying means of filtering results by type (all, images, videos, news, etc.) only after you’ve begun your search (Figure 4-4). This helps to keep people focused on the more meaningful task at hand, rather than being overwhelmed with decisions at the outset.

Figure 4-4. Google simplifies the initial task of searching (left) and provides the ability to filter results only after the search has begun (right) (source: Google, 2023)

Let’s look at another example of Hick’s law. Onboarding is a crucial but risky process for new users, and few applications nail it as well as Notion (Figure 4-5). Notion helps beginners learn the basics of its product by providing an easy-to-follow checklist for getting started. This is an effective way to onboard users because it mimics the way we actually learn: we often learn best by doing and building upon what we already know. By providing steps in a risk-free environment, we can enable new users to start interacting with an app without them feeling overwhelmed by an endless amount of possibilities for getting started.

Figure 4-5. Screenshot from Notion’s progressive onboarding experience (source: Notion, 2023)

Another common example of Hick’s law in action can be found with streaming services and the choices we’re presented when deciding on what to watch. Take, for example, Netflix, which found that its customers took an average of 18 minutes to find a show or movie. The reason for this was they were often paralyzed with indecision when it came to selecting a show or movie based on the quantity of options in front of them. To help remedy this, Netflix introduced various features such as “Trending Now” and “Popular on Netflix” (Figure 4-6) as ways to provide more weight to specific options through the social proof that others have enjoyed them.

Figure 4-6. Netflix’s “Trending Now” and “Popular on Netflix” sections provide more weight to specific options via social proof (source: Netflix, 2023)

TECHNIQUECard Sorting

As we’ve seen in the previous examples, the number of choices can have a critical impact on the time it takes for people to make a decision. This is especially important when it comes to enabling users to find the information they need. Too many items can lead to more cognitive load for users, especially if the choices aren’t clear. Conversely, with too few choices it becomes more difficult for users to identify which item is most likely to lead them to the information they’re looking for. One particularly useful method for identifying users’ expectations when it comes to information architecture is card sorting. This handy research method is great for figuring out how items should be organized according to people’s mental models: simply have the participants organize topics within groups that make the most sense to them (Figure 4-7).

Figure 4-7. Card sorting

The steps required during this exercise are relatively straightforward. While there are a variety of approaches to card sorting (closed versus open, moderated versus unmoderated), they all follow the same general process. The following are the steps that make up a moderated open card sorting exercise,⁴ which is the most common type:

1. Identify topics

The first step is to identify the topics that the participants will be asked to organize. These topics should represent the main content within your information architecture, with each item written on an individual card (the exercise can also be conducted digitally). It’s recommended that you avoid labeling topics with the same words, which can bias participants and lead them to group these items together.⁵

2. Organize topics

The next step is to have the participants organize the topics, one at a time, into groupings that make sense to them. It’s common to have participants think out loud during this phase, which can provide valuable insight into their thought processes.

3. Name categories

Once the topics have been organized into groups, ask the participants to name each group they created based on the term they think best describes it. This step is particularly valuable because it reveals what each participant’s mental model is and will be helpful when determining what to eventually label categories within your information architecture.

4. Debrief participants (optional)

The optional but recommended final step during an open card sorting exercise is to ask the participants to explain their rationale for each of the groupings they created. This enables you to uncover why each participant made the decisions they did, identify any difficulties they experienced, and gather their thoughts on any topics that might have remained unsorted.

KEY CONSIDERATIONOversimplification

An important goal for designers is to eliminate unnecessary complexity for the users  of the products and services they design—to become elegant simplifiers. After all, good user experiences are often those that feel easy and intuitive, and where obstructions that might deter people from achieving their goals have been removed. As we’ve seen, simplifying an interface or process helps to reduce the cognitive load for users and increases the likelihood that they’ll complete their task and achieve their goal. But a balance must be struck when striving for simplicity, and it’s important not to take simplification too far. When an interface has been simplified to the point of abstraction, it’s no longer clear what actions are available, what the next steps are, or where to find specific information. In other words, the amount of visual information presented has been reduced to make the interface seem less complex, but this has led to a lack of sufficient cues to help guide people through a process or to the information they need. As a result, the amount of cognitive load required for users to achieve their goals has increased.

A common example of this is the use of iconography as a way to communicate critical information about possible actions (Figure 4-8). Using icons has a lot of advantages: they provide visual interest, they save space, they present excellent targets for taps or clicks, and they can provide quick recognition if they hold universal meaning. The challenge is that truly universal icons are rare, and icons often mean different things to different people. While relying on icons to convey information can help to simplify an interface, it can also make it harder to perform tasks or find information. This is especially true if the icons aren’t immediately recognizable to users, who more often than not will have a wide spectrum of knowledge and experience.

Figure 4-8. Screenshot of the app bar from Facebook’s iOS app (source: Facebook, 2023)

Another complicating factor is that similar icons may be used to represent different actions or information, sometimes in complete opposition, from one product or service to another. There is no icon standardization body that regulates what icons can be used where in websites or apps, which means that how icons are used is left to the discretion of the designers and their teams. We know that an icon can represent different things to different people, but what about when the same icon represents different actions? Since there is no standardization, the functionality attached to an icon can vary from one digital experience to another. Take, for example, the “heart” and “star” icons: they typically indicate the ability to favorite, like, bookmark, or rate an item, but they may sometimes simply indicate a featured item. Not only does the meaning and functionality of these two icons vary across different products and services, but they also often compete with each other. This obviously results in confusion and an increase in the cognitive load on users, because the icons’ meaning is hard to interpret precisely.

Adding contextual clues helps users to identify the options that are open to them and the relevance of the information available to the tasks they wish to perform. In the case of iconography, studies have shown that simply adding text labels to accompany icons will provide clarity and aid users with both discovery and recognition. This practice is even more critical when using icons for important elements such as navigation (Figure 4-9). The addition of text labels effectively reduces the abstraction of the icons alone by including additional information to help convey meaning and increase usability.

Figure 4-9. Text labels accompany icons in the navigation on the X (formerly Twitter) web app (source: X, 2023)

Conclusion

Hick’s law is a key concept in user experience design because it’s an underlying factor in everything we do. When an interface is too busy, actions are unclear or difficult to identify, and critical information is hard to find, a higher cognitive load is placed on users. Simplifying an interface or process helps to reduce the mental strain, but we must be sure to add contextual clues to help users identify the options available and determine the relevance of the information available to the tasks they wish to perform. It’s important to remember that each user has a goal, whether it’s to buy a product, understand something, or simply learn more about the content. I find the process of reduction, or eliminating any element that isn’t helping the user achieve their goal, a critical part of the design process. The less they have to think about what they need to do to reach their goal, the more likely it is they will achieve it.

¹ “Why Do We Have a Harder Time Choosing When We Have More Options?,” The Decision Lab, August 16, 2018, https://oreil.ly/mmpYT.

² Barry Schwartz, The Paradox of Choice: Why More Is Less (New York: HarperCollins, 2004).

³ Sheena S. Iyengar and Mark R. Lepper, “When Choice Is Demotivating: Can One Desire Too Much of a Good Thing?,” Journal of Personality and Social Psychology 79, no. 6 (2000): 995–1006.

⁴ In a closed exercise, the groups are predefined by the researcher.

⁵ Jakob Nielsen, “Card Sorting: Pushing Users Beyond Terminology Matches,” Nielsen Norman Group, August 23, 2009, https://oreil.ly/bxhNN.