How to deal with students who refuse to do anything except take exams?
Welcome to higher education! Students will use formal assesement to guide their learning, and no amount of cajoling, or appealing to their sense professional or intellectual propriety will change that. Some students will always work above and beyond what the assessment requires of them, but most won't.
Assessment is how students comprehend what is the stated aim of a course. Instead of fighting against it, you might embrace it. For each learning outcome there should be an assessment that is aligned with that outcome - that is, it is impossible to successfully complete the assessment without have met the learning outcome. The learning activities are then designed to meet the outcomes. This might seem like &quot;teaching to the test&quot;, but in fact it is the opposite: in &quot;teaching to the test&quot;, the assessment defines learning outcomes, here the learning outcomes define the assessment. Biggs and Tang [1] refer to this as &quot;constructive alignment&quot;. [1] is a good read for the evidence that students have more or less always measured what they are supposed to learn by what they are assessed on.
Thus you would ask &quot;what learning outcome am I hoping my students achieve by this homework, and where is that assessed?&quot;. If the learning outcome isn't assessed anywhere, then it should be. If it doesn't meet a learning outcome then perhaps it shouldn't be set.
In practice we either make homework credit bearing (even if only a tiny percent of the overall credit), or, more frequently, ask an exam question that tests the learning outcome that a homework is aimed towards, and a student won't be able to answer without having done the homework. The final possibility is that the homework is practice for what will be tested in the exam. In this case you need to make this abundantly clear to the students. Even then, you will probably only get a fraction of the class doing it. The consolation is that this is the part of the class that deserves to do better in the exam and undoubtedly will.
[1] Biggs, J and Tang, C. (2011): Teaching for Quality Learning at University, (McGraw-Hill and Open University Press, Maidenhead)