First cause-effect: In memory or social perception, the first information to appear is often remembered firmly and accurately or the most impressive impression on the individual. Which of the following is a prime effect? ["Dai Li's deepest memory of the class teacher is his smile at the first meeting. Although the class teacher often smiles later, it is not as charming as when he first met.", 'Zhou Ping found that Manager Wang of the Human Resources Department was particularly warm and sincere to others. After he returned home, he kept telling his family how good Manager Wang was.', 'Two elementary school students met by chance 30 years later, and they all talked about the mutual description of each other at the graduation ceremony of the primary school.', 'Lao Li often remembers only the things at hand but not the past.']