 UX designers can only design a product knowing the person who is going to use it. This is where understanding of psychology in UX design comes into play. Here's four essential psychological principles that you can use in your design. The first principle is the principle of least effort. People always look for ways to complete tasks with the least possible effort. The simplest designs usually are the most attractive ones. Principle two, the principle of socialization. People want to be social and they can rely on technology to help them feel more socially accepted. Implement social media buttons, product reviews and ratings to leverage social validation in your product.