Law of similarity

Synonyms: Invariance

Our brain groups similar objects to understand the surroundings better. The grouping criteria are the visual presentation of the objects such as the shape, color, the size of the objects. So the similar objects will be included in a category with the name tag. Our brain does it to analyze a big number of objects.

Why to Use It

This is how the law of similarity can help to improve our design.


1. Spend less time finding something

In this case, we want to speak about the location of the visual elements. The Apple website is quite simple but you can find all the information you need. The informational blocks are always on the upper line, and at the end of the website. So you don’t need to navigate more than 30 seconds to find the Apple Podcasts section. You just go down and find the second column.

2. Similar visual elements maintain users on their path to the end of the task

The user flows to the end of the task - buying or subscription - can be faster with similar elements. The user’s eye will catch the same elements and follow them. Let’s buy something at When we see similar elements - Shop Women and Shop Men - we recognize that all the products lie upon these two buttons. Afterward, we see the sections with different types of clothes. The square shapes of the sections will show us that now we can choose the clothes we want.

3. The law of similarity makes the interactions intuitive

Intuitive interfaces make our users feel good, not frustrated. You know what we are talking about if you have ever used the poor build website. All the needed elements should be visible. Categorize them by size, colors or shapes, so the user can easily navigate your website.

4. The law of similarity helps to involve users

The law of similarity describes how our brain works, and this knowledge can save the nerves of our customers. When we create friendly and intuitive interfaces people appreciate it.

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