1) Adult learners make up 40% of college students in the US and are defined as those over age 25 who participate in formal or informal education beyond high school. 2) Malcolm Knowles identified adults by those who fulfill adult roles like worker or parent and those who see themselves as responsible for their own lives. 3) Knowles is considered the father of adult learning theory which is based on the idea that adults learn differently than children with a focus on experience, problem-solving, and relevance to real-life situations.