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Unlike short-term memory, long-term memory stores information for a long time. It builds through repetition and familiar patterns.
UX designers can use long-term memory by creating consistent layouts or icons, so users learn to recognize them over time. This way, users won’t have to “relearn” how to use your design every time they visit.
Key UX metrics related to long-term memory are learnability and efficiency. How fast can users use the system the first time and how fast can they get better at using it?
Jakob’s law can help with improving learnability and efficiency.
Jakob’s Law
Users spend most of their time on other websites, so they expect your site to work like all the other sites they already know.”
This one is closely related to learnability. Common design patterns and by extension, design systems, help users use new systems (apps, websites, etc.) quickly. This is because they already have an existing mental model as to how something should look and function within their long-term memory, and they’re able to pull this information quicker.
A simple example is a button. A primary button is usually rectangular and has high emphasis, like colour fill and shadow. A star-shaped, dull-coloured button may not be perceived as a button for users. It may take some time for them to figure out that that “thing” is a button and is interactive.