Cognitivism is a learning theory that focuses on the internal mental processes involved in learning such as thinking, memory, and knowledge acquisition. It views learning as an active process where learners build knowledge based on their experiences. Key figures in cognitivism include Howard Gardner who developed the theory of multiple intelligences, Benjamin Bloom who identified levels of learning, and Robert Gagne who outlined nine instructional events. To implement cognitivism, teachers should use instructional methods that engage different types of learners, incorporate interactive activities, and assess students in varied ways that accommodate different learning styles.