Hick's Law in UX design – A beginner's guide

What is Hick's Law?

Hick’s Law (or the Hick-Hyman Law) is named after psychologists William Edmund Hick and Ray Hyman. In the early 1950’s, they set out to understand the relationship between the number of stimuli present and an individual’s reaction time to any given stimulus. 

The parameters at play in Hick’s law are:

• Time 

• Choices

• Complexity

As you would expect, the more stimuli a person is presented with, the longer a person will take to reach a decision. Users bombarded with more choices need more time to make sense of their options and make a decision. 

How to define Hick’s Law

The formula for Hick’s Law is: RT = a + b log2 (n)

• RT = Reaction time 

• “a” and “b” = Arbitrary measurable constants that depend on the task that is to be carried out and the conditions under which they’re carried out. 

  1. a = Time that is not involved with decision making

  2. b = Empirically derived constant based on the time it takes to cognitively process each option (approximately 0.155 seconds)

• log2 =  logarithm function

• (n) = the number of equally probable alternatives/the number of stimuli/choices present.

Using this formula allows designers to calculate the relationship between the number of stimuli and an individual’s reaction to any given stimulus.

Example

Let’s say your phone starts playing a sound. 

It takes three seconds to detect that the sound is an alarm you set the day prior (...because we’re all human). So  a = 3 seconds. b = 0.155 sec. When trying to turn off the alarm, there are four options present: Snooze, stop, the home button and the power button. So n = 4. Now let’s plug these numbers into the equation to find the user's response time.

Using the above formula, the time to respond would be: (3 sec) + (0.155 sec)(log2 (4)) = 3.31 sec.

Now, let’s consider what happens if there were eight buttons to turn off the alarm instead of four? The response time would be 4.31 sec and increases logarithmically with the number of options presented. 

Hicks Law is all about keeping it simple! If users spend too much time making a choice then their experience suffers.

What are Hick’s Law examples?

You can find applications of Hick’s Law everywhere, not just in web and app design. Let’s take a look at a few examples.

If you had to pick a car, which would you pick?

What about now?

It’s much easier and quicker to choose between two cars than 16 cars, right? Here’s another Hick’s Law example.

Old cable TV remotes (left) have so many buttons that users needed a manual to explain how to use them. Apple’s reaction? Make the remote simpler (right) so users don’t have to spend time figuring out how to use it.

Even Google's evolution of their home screen has been optimised according to Hick’s law.

​​Just look at Google in 1998 (top), there were so many more options that crowded the page. In 2020 (bottom) the options are very limited, reducing the time it takes for a user to make a decision, performing the key action they want to undertake (searching the web) much easier.

How to apply Hick’s Law as a UX designer

Hick’s Law helps users simplify their decision-making process (and time taken) but at the same time not completely remove their choices. Applying Hick’s Law allows designers to balance user choice and complexity to avoid frustration or information overload, which leads users to making poor choices or abandoning the task or site.

Designers use Hick’s Law to: 

• Direct users to functions of their top priority

• Help users reach CTA’s and goals faster

• Support better conversion rates 

• Ensure user’s do not get confused

There are many ways designers use Hick’s Law. Here is a summary of the 6 most common applications by UX designers. 

1. Use categories

When it comes to grouping lots of content and making it scannable and scrollable, Netflix and other streaming platforms nail it. Netflix groups large amounts of content largely by genre but they also categorise based on:

• Original content

• Personalised content

• Popular and trending content

A user can explore many genres at a glance or dive into the ins and outs of the genre that’s most relevant to them.  

We see the use of Hick’s Law to categorise themes in ‘sliding carousels’. Another great example of categorising content could be ‘cards’ for an ecommerce store that quickly guides a user to women’s, men’s or kids clothing based on what they’re looking for.

2. Group navigation 

Just as you would group similar content into categories, grouping of related navigational items is an important part of making lots of content quickly findable. The Australian online shop THE ICONIC does this well. 

THE ICONIC groups thousands of products within a navigational structure that allows a user to narrow down what they’re looking for based on clothing, for example:

• User group

• Type

• Brand

• Range 

• Edit

We see THE ICONIC apply Hick’s Law to navigation design by implementing mega menus or drop-down menus. While this works well for a brand such as THE ICONIC, Amazon applies Hick’s Law to their navigation by prioritising search above all else. 

3. Simplify forms (sign up/check-out)

Users don't love completing forms. That’s why sign up forms or check-out experiences started allowing users to register with 3rd party accounts (such as Google or Facebook). It saves time, makes things easier for the user and speeds up their journey. Social login makes it super simple to sign up for a new product. Pinterest and other web applications implement this social login strategy to increase conversion rates. 

This method reduces friction through a one-click sign up (instead of filling out multiple form fields and selecting yet another password, users need to remember). Data shows that companies who provide social sign up will increase conversion by 20-40%. Now, that’s big! 

Whilst social sharing doesn’t work for every form, many forms can be optimised through Hick’s Law by removing all unnecessary fields and making relevant forms multi-step.

4. Simplify content

Similar to the above, users don’t love reading either. In fact, they scan websites, only reading approx. 20-28% of what’s on a page which means it’s important to resist the temptation to fit everything on a single page without rhyme or reason. The accounting software Xero does this well for landing pages by having a clear visual content structure that explains the proposition and just the minimum content needed for a user to take the desired action: ‘try Xero for free’. The first 2 modules (as seen in the image below) serve a clear purpose:

1. Showcase the proposition and key features of the product

2. Showcase social proof and built trust in the outcomes

Xero applies Hick’s Law by removing all unnecessary content (including the navigation or links to other website pages) as well as following the principles of good content design.

5. Easy sharing

When providing a set of sharing options, focus on the feature of sharing first. THEN, show the options for sharing. No need to show it all upfront. Airbnb does this really well.

When Airbnb incorporated this strategy (rather than showing all options upfront) they reported a 52% increase in shares. Designers often loosely refer to this as progressively showing features. 

6. Hide options

Similar to the above, sometimes ignorance to all the options (until you want to take action) is bliss. Spotify does this well by showing users what they need to see to find and play a song. But if a user right-clicks they have other options:

• Go to radio or album

• Show credits

• Save 

• Add to playlist 

• Share

Spotify does well to hide complex features and options… until the user wants them, in which case they’re just one click away.

Let’s summarise Hick’s Law in UX design

• Hick’s Law states that having too many options makes it harder for users to make a decision. As a result, they abandon the flow (or make mistakes). 

• Showing less options to users = less time to make a decision – and vice versa.

• Simplify the decision making process and actions taken by breaking down complex tasks into smaller steps.

• Reduce the number of navigational options for users. Card-sorting can be used to define categories and refine the information architecture. 

• Use qualitative and quantitative data to identify the main tasks that a user would like to achieve. Focus on these! 

• Avoid overwhelming and stressing users by highlighting the recommended options (and de-prioritise others).

• Use progressive information to minimise cognitive load.

Whether you're designing a site map, homepage, menu items, shopping cart, payment process, or something else, there’s an art to nailing down the right design decision that perfectly captures the concept of Hick’s Law. There are many factors at play which is why it helps to hire the experts who have the tools and expertise to make the right decision that works best for each business and user case. 

Contact Honest Fox if you want to level up or implement the principles of Hick’s Law to your website or app.