Anecdotally this fits with my experiences on death march projects. I've often seen people learn a new programming language and/or set of libraries while on a t

Anecdotally this fits with my experiences on death march projects. I've often seen people learn a new programming language and/or set of libraries while on a tight deadline and getting yelled at for being behind schedule. Their knowledge retention is drastically worse than when they're on a more relaxed project. In my experience, someone who takes an unhurried week to do a small project in an unfamiliar environment will learn a lot more than someone forced to spend a month frantically trying to make a deadline in that same environment. An interesting corollary is that someone who really cares about their job may end up being less effective in the long run than someone who does. Specifically, someone who cares about making their insane deadlines and who gets stressed at the thought of looking bad will end up retaining less knowledge about the programming languages and libraries that they use. They'll also be more inclined to copy/paste code without really understanding it just to make their deadline, etc. Conversely, when someone who doesn't care much about their company's priorities is given a task, they can take a more relaxed attitude and learn much more. They might say, "Well I'm supposed to finish this C# program in 2 days, but if I take 1 extra day then I can learn how to use the .NET logging framework, figure out how to use delegates, and really understand how its threading model differs from pthreads." In the long run, this employee will probably be more effective than the ones who listen to their managers and try to finish everything now-now-NOW! And according to the OP, they'll probably retain what they learn much better as well, which definitely fits with my experiences.