#  Leveraging asymmetry in student's prior knowledge through peer learning exercises 

 



 ![Salil Vadhan](/sites/g/files/omnuum12666/files/vpl/files/salil_vadhan_240.jpg)

 

**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*](https://locator.tlt.harvard.edu/course/colgsas-218613/2022/fall/16532), 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.”

## The benefits

The “Sender-Receiver” exercise proved to be an effective tool for engaging students across a wide range of mathematical backgrounds and developed students’ skills for communicating complex ideas at multiple levels to their peers. Over time, students discovered which strategies worked best for them when tasked with the “Sender” role and reflected on the value of learning through two-way dialogue. By the end of the semester, some students had even adopted the protocol for their study groups to prepare for exams.

> *"One of the things that draws us to teaching is that through the process of explaining, we come away with a much deeper understanding than we had before.”*

## The challenges

One of the core challenges of peer learning exercises in courses with a wide range of background knowledge is ensuring that “everyone comes away feeling like it was a valuable experience for them.” Oftentimes it leaves behind students who get lost in the material, and students who are most comfortable feel like they haven’t learned anything new. In implementing these exercises, it’s crucial to be intentional about the concepts you select and be attentive to how the conversations are progressing.



 

##  Takeaways and best practices 

 



 ### Calibrate the complexity.

This exercise relies heavily on the “Sender” students coming to class prepared. It’s essential that instructors calibrate the complexity of the concepts these students need to grasp to ensure that the time can be used most effectively. If the concept is too difficult, students will be lost, but if it is too simple, the exercise won't generate as much conversation. Instructors should also be mindful of the balance between student-led instruction and providing an instructor-led digest of the concepts.



 

 ### Encourage collaborative spirit and reflection.

Active learning exercises provide a way for emphasizing a collaborative, rather than competitive or adversarial, spirit in classes. To formally support this dimension, students in COMPSCI 120 were expected to complete a short reflection survey after each activity and maintain a participation portfolio documenting the best examples of where they helped advance their classmates’ learning or improved the class.



 

  

 

 

 

### Bottom line

Active learning exercises like the “Sender-Receiver” peer learning activity used in [COMPSCI 120](https://salil.seas.harvard.edu/classes/intro-algorithms-and-their-limitations-fall21) can be an effective tool for developing a sense of community of learners, increasing student engagement, and helping students build skills for communicating complex information to other students with different knowledge backgrounds.



 

##  Related research 

 



  [### Use of an Online Social Annotation Platform to Enhance a Flipped Organic Chemistry Course

 ](https://hollis.harvard.edu/permalink/f/1mdq5o5/TN_cdi_openaire_primary_doi_3edf0cc0257f3e772cd7cb62f76426bd) An online social annotation platform, Perusall, was incorporated into a flipped organic chemistry course sequence. The platform provides an interactive chat enhanced with social media features that facilitates student engagement with each other as they... 

 

 

   [### Collaborative Online Annotation: Pedagogy, Assessment and Platform Comparisons

 ](https://hollis.harvard.edu/permalink/f/1mdq5o5/TN_cdi_doaj_primary_oai_doaj_org_article_561f4103b464423d81e5a3fdee908a44) Annotating a text while reading is commonplace and essentially as old as printed text itself. Collaborative online annotation platforms are enabling this process in new ways, turning reading from a solitary into a collective activity. 

 

 

   [### Use of a Social Annotation Platform for Pre-Class Reading Assignments in a Flipped Introductory Physics Class

 ](https://hollis.harvard.edu/permalink/f/1mdq5o5/TN_cdi_doaj_primary_oai_doaj_org_article_2a22610bbac2444c8d335e9804bd22cd) In this paper, we illustrate the successful implementation of pre-class reading assignments through a social learning platform that allows students to discuss the reading online with their classmates. We show how the platform can be used to understand how... 

 

 

  

 

 [ More Research arrow\_circle\_right ](/intopracticeresearch) 

 

 

 

##  Related resource 

 



  [### Ask a Librarian

 ](https://ask.library.harvard.edu/) For questions related to course materials that may not be immediately available through social annotation tools like Perusall, Ask a Librarian. 

 

 

   [### Interested in hearing from a faculty member using Perusall?

 ](/links/interested-hearing-faculty-member-using-perusall) Interested in hearing from a faculty member using Perusall? Watch this video of Professor Eric Beerbohm from VPAL’s Debate as Pedagogy event explaining how he used the platform to launch class discussions. 

 

 

   [### Introductory video from Perusall’s founders

 ](https://www.youtube.com/watch?v=_PfAc0D2erk) Interested in learning more about Perusall? Check out this introductory video from Perusall’s founders 

 

 

  

 

 [ More Resources arrow\_circle\_right ](/intopracticeresources) 

 

 

 

 



 

 See also:- [ SEAS ](/featured-faculty/seas)
- [ Into Practice Issues ](/practice-categories/practice-issues)
- [ active learning ](/activelearning)
- [ peer instruction ](/peerinstruction)
- [ collaborative learning ](/topics/collaborative-learning)