Salil Vadhan, Vicky Joseph Professor of Computer Science and Applied Mathematics & Lead PI on Harvard’s Privacy Tools Project, teaches COMPSCI 120: Introduction to Algorithms and their Limitations, a new introductory course in theoretical computer science “aimed at giving students the power of using mathematical abstraction and rigorous proof to understand computation with confidence.” Many computer science students are “builders” who enjoy the creative aspect of the field, yet their mathematical backgrounds are often quite diverse; to some, mathematical theory is unfamiliar. In redesigning the undergraduate computer science curriculum, it was a priority to make this “new language, reasoning, and way of thinking” accessible to students early in the program.
Vadhan supplemented traditional assignments, lecture material, and teaching fellow support with novel “Sender-Receiver” exercises, which were used repeatedly throughout the semester. In designing these, he worked with research associate Robert Haussman and postdoctoral fellow Deniz Marti from Harvard’s Learning Incubator (LInc).
In these exercises – where half the students are assigned to be “Senders” while the other half are “Receivers” – “Senders” review a mathematical proof and come to class prepared to teach a “Receiver” classmate both the high-level gist of the proof and some of the formal details. Students are randomly assigned into pairs for the interactive dialogue. Throughout the conversations, they practice engaging in and communicating across varying levels of conceptual complexity and, by the end, come away with a deeper understanding of the proof. Vadhan noted that “right from the first execution of it, we were really happy with what we saw happening in the class.”