The Von Restorff Effect
The Von Restorff effect was recognized by Hedwig von Restorff in 1933. She conducted a set of memory experiments around isolated and distinctive items, concluding that an isolated item, in a list of otherwise similar items, would be better remembered than an item in the same relative position in a list where all items were similar. The Von Restorff Effect, predicts that when multiple similar objects are present, the one that differs from the rest is most likely to be remembered. This refers to the phenomenon where people value a thing differently depending on whether it is placed in isolation and whether it is placed next to an alternative. In particular, a certain choice can be made to look more attractive if it is placed next to an alternative relative to which it is distinctively better in some respect.
This is the main reason why all call-to-actions look different from the rest of the action buttons on a site or application. We want users to be able to differentiate between a simple action button and a CTA, in order for them to have a clear understanding what the CTA does, while also remembering it throughout their use of the application or site.
Too many people think that plastering your brand color all over the page is the only way to make the brand memorable .We can draw user's attention to the places we want them to see or feel. For example, if we want the user to feel the color of your product as blue, we can add little blue around while another monochrome scheme is being used or we can add little blues to important action buttons to make them easily distinguishable while rest of the page is in greyscale.
If we want to emphasize a text in your presentation that we want an audience to read and remember, we need to make it different. Or if we want to show the important dates for our party in the poster, we need to make them different from the rest. So if we are building a user interface, and want people to follow certain things to improve the experience, differentiate items by their colors, shapes or sizes. While making this, be careful when we force a user to focus on certain parts of your user interface. if we end up with making too many different shapes or colors, users can be easily distracted with the noise. Maintain a balance to make cleaner interfaces with correct emphasis on relevant elements. If we use too many distinctive elements, we'll end up creating a messy UI which generates too much cognitive load on the user.
While designing interfaces, making an item different from the others affects the users' attention, by getting inside their heads and attracting their emotions. This can be done to improve the user experience through emphasizing particular information or making certain actions salient.