design thinking, Interface Design, usability testing, User Behaviour, User Experience, UX Concepts, UX Knowledge, UX Methodology

Fitts’ Law in UX

Paul Fitts:

One of the founding fathers of Ergonomics, his famous “Fitt’s Law” (which predicts the time required to rapidly move to a target area, such as a button or control) is still in use today. Fitts was a psychologist who later served in the Air Force, where his work redesigning cockpits did a lot to improve aviation safety.

Relevance to UX:

It tracks the time it takes to point at something. Taking into consideration the size and distance of the target. Fundamentally it proves that its faster for you to hit larger targets closer to you than it is to hit smaller targets that are farther away from you.

If you look at the keys on your computer keyboard you will notice that the keys users press more often like the ‘enter’ key the ‘space bar’ and the ‘shift’ key are larger than the other modifying keys. These keys are larger so they are easier to hit.
They are also closer to the alpha numeric keys.key-board

Keys that are used less often like ‘alt’ delete’ ‘esc’ are farther away from the alphanumeric keys.

Similarly when designing an interface when a designer wants users to interact with their website interface or product they make sure they make it obvious. Targets or Buttons are easily located and easy to use. (Refer Below Image)

homepage.png

Its also signifies that the farther away a users mouse is and the smaller the onscreen target is the longer it takes for a user to move the cursor and click on target. (Refer Below Image)

yahoo.png

Fitts Law of Curve:

For Small Size Objects:

The size of the target matters. The larger the target the easier it is to hit.

button.png

This might lead us to think that the larger buttons are always better. However this rule cannot be applied always. Fitts Law works on curve. Which means smaller objects are easier to click if they are made large.

small-to-big.png

For Large Size Objects – The Gutenberg diagram :

However larger objects are already large. So if they are made larger yet they won’t be easier to click. Because of this curve the benefits of increased size begin to decrease. This ensure proper proportions are given to objects and that the purpose is served for the same.

Placement of Objects Onscreen – :

Actual physical placement of your screen elements are very important. The Gutenberg Diagram shows that the users tend to move through the screen from TOP LEFT to BOTTOM RIGHT. Therefore important objects and buttons must be placed in the BOTTOM RIGHT.

fb.jpg

Enter a caption

Designing in proportion and keeping in mind their appropriate usage is critical.

 

Text Links or One Word Link :

Always try and make a phrase a link rather than just one word.  (Refer image Below)

This makes the target link bigger and easier to click and understand.

phrase-link.png

 

Design for Different Devices :

Proper size, spacing and proportion of objects are crucial. Every item must be in sync and proportion to the other designed for serving the usage they are meant for.

 

Cheers,

RuthlessUX.com

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