From my experience as a Caltech undergrad, there was a "tragedy of the commons" in some of the larger classes. A student had a choice of doing the work early en

From my experience as a Caltech undergrad, there was a "tragedy of the commons" in some of the larger classes. A student had a choice of doing the work early entirely on their own, or waiting until their classmates had started working on it, and being able to exchange advice, compare approaches, or verify answers with those classmates. Thus there was a fairly strong dis-incentive to always being the first to dig deeply into an assignment, unless you were so much smarter than your classmates that their cooperation was useless to you.