Psychology Principles of UX Design

There is so much more to design than what meets the eye. It’s especially important to understand the people you are designing for. Psychology laws and principles and knowing how to apply them are essential for good design. This article looks at a few of them and how they can be applied.

Hick’s Law

The amount of time that it takes someone to make a decision depends on the number and complexity of the choices present. The greater those variables are, the longer it will take to make a choice. The point is to simplify the decision-making process by creating higher-level categories and breaking down complex processes into simpler ones with fewer choices.

Duolingo’s onboarding process, as seen above, does a good job of applying Hick’s Law to make a complex process easily digestible. Each step appears on its own screen with a limited number of simple choices.

How to apply Hick’s Law:

  • Minimize the amount of choices by categorizing them into higher levels
  • Simplify complex processes by breaking them down into smaller, more digestible steps. This includes making a purchase and onboarding process, as seen in the example above.

Fitts Law

The amount of time it takes to acquire a target depends on the size and distance to the target. The larger the distance is, the longer it will take to reach and the smaller the size, the longer it will take to select. Interactive elements should be larger

The app Typewise(A) applies Fitts law to the ios keyboard by creating larger targets. Compared to the standard ios keyboard (B), which some believe is too small and difficult to use, their size makes them easier to tap.

How to apply Fitts Law

  • Increase the size of touch targets so they can be accurately selected
  • Place touch targets in areas of the interface where they can be easily selected (thumb zone on mobile apps, edges on desktop)
  • Place touch targets of the same sequence close together

Von Restorff Effect

When multiple similar objects are present, the one that is different will be remembered. This is also known as the Isolation Effect.

On Drop Box’s pricing page, the Advanced option stands out from the others and is labeled as the best value. The user is directly drawn to it and is more likely to remember the features and choose this option.

How to apply Von Restorff Effect:

  • Use distinctive visual features such as colors, shapes, and sizes on items to make it more memorable and influence the user’s choices
  • Use this sparingly and make sure this element isn’t overused or else it will cause the user to be distracted.

Jakob’s Law

Users spend most of their time on other sites. Therefore, they expect your site to act similar to the other sites that they know.

Both examples above are from e-commerce product pages, Bloomingdales (A) and ASOS (B). They both follow the pattern common to most product pages and consist of mostly the same elements.

How to apply Jakob’s Law

  • Becoming familiar with common design patterns is probably the best way to ensure a design follows what users find familiar
  • Research and understand the sites that a particular target audience uses to understand the particular products they use

Miller’s Law

The average person can keep 7 (plus or minus 2) items in their working memory at a time. Because users have a relatively short-term working memory, chunking should be used to make content more easily digestible.

Sephora chunks similar items into categories on its homepage

How to apply Miller’s Law

  • Chunk content and information into easily, scannable groups

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