Redundancy Principle, Coherence Principle, Signaling Principle, Contiguity Principles. These four theories are very practical. Whether it is a learning method or used in daily communication and expression, it is effective. In fact, when expressing or learning, first remove unnecessary information, let yourself or others get the most important information points, and use images, dynamics, and colors to assist memory. I watched this video of my own choice. During his speech, he used the four theories I mentioned. When he mentioned details or data, he would provide charts to help viewers understand and remember. When it comes to geographic location and ways, maps and icons are also used to highlight the key points. At the same time, he also highlighted that the business Amazon is doing is conducive to the ecology of the earth, not only expressing that Amazon is a big company, but also showing that this company has a worldview. Therefore, no matter in our daily communication or learning, it is effective to reduce unnecessary information as much as possible, and use images or colors to help us remember.