Doherty Threshold: Propounded by Walter J. Doherty and Ahrvind J. Thadani states that “neither the user nor the computer should have to wait for each other”. The average interval between request and response should be less than 400 milliseconds. Keeping users waiting longer reduces productivity and loses attention. To achieve this both Front and Back-end engineers need to work together. For instance, back-end engineers ensure that frequently accessed resources are cached in-memory using a caching tool like Redis while Front-end engineers ensure that scripts and styles are minified and served only when needed.
Aesthetic and Usability Effect: An aesthetically pleasing design was studied in 1995 by Maasaki Kurosu and Kaori Kashimura from Hitachi design centre. They found out that users are more tolerant of minor functional defects, so far as an app is aesthetically appealing or beautiful. Keep in mind that the front-end of an application is what users interact with, as such it should be given the attention it deserves, to reflect the brand whilst allowing users to carry out functions seamlessly.
Fitts Law: Size and distance. The time to acquire a target is a function of the distance to and size of the target. The target here are buttons, links and Call To Actions (CTAs) users interact with. These should be conspicuous and strategically placed. As an example, an E-commerce site will not have the “Add to cart” button hidden at the footer of the product page, if the goal is to convert visitors to customers.
Jakob’s Law of Internet User Experience: “Users spend time on sites other than your site. They prefer your site to work just like other sites.” This law essentially discourages web developers from being too innovative to the extent where users are unable to interact with their products simply because it requires a steep learning curve.
Occam’s Razor: “Among competing hypothesis that predicts equally well, the one with the fewest assumptions should be selected”. In design, we strive to keep it simple. Not reaching for complex solutions where simpler ones would not just suffice but be perfect.
There you have it. Thanks for reading.
Did you spot a typo, an error or want to contribute? Here's the repo on GitHub