At the Pennsylvania College for Women (now known as Chatham University), as in high school, Carson was a bit of a loner. She originally studied English, but switched her major to biology in January 1928. She continued writing in the school's student newspaper. Though accepted to graduate school at Johns Hopkins University in 1928, she had to remain at the Pennsylvania College for Women for her senior year because of money problems. She graduated "magna cum laude" (highest honors) in 1929. After a summer course at the Marine Biological Laboratory, she continued her studies in zoology and genetics at Johns Hopkins in the fall of 1929.