I'd like to know what aspects of undergraduate study you think contribute most to the way students learn, and their learning outcomes, which can be their grades or other measure of intellectual and academic ability.
As you certainly well know, learning is cyclic information processing. Therefore, for responding to your question, it is helping to know about a modern model of learning that is based on outcomes of neurosciences. If you drop me an e-mail to [email protected], I could send you a copy of a paper on such a model, if you like. (I have presented it at 2011 IEEE Global Engineering Education Conference (EDUCON) in Amman, title: Fairly Certifying Competences, Objectively Assessing Creativity). The paper is under IEEE copyright.
There are different classes of learning outcomes (knowledge in the wider sense): knowledge (in the narrow sense), skills, and competences. Roughly speaking, knowledge (in the narrow sense) is what you learn by heart, skills is what you acquire by training, competence is the ability to solve non-standard problems by comparative reflection.
In order that learners are going to learn, there is one thing that is indispensable:
motivation, motivation, motivation,
since motivation is the door-opener to essential subprocesses of learning. As better motivation is, as more probable it is that our "executive device" (part of the "working memory" cf. Baddeley and Hitch) initiates the next step in consolidating our memory.
Therefore, our first and most important task as educators is it to motivate learners. This is sometimes difficult, as we all know, particularly, if we need to motivate our learners to learn by heart, or to train routine jobs, since here is a point where learners need to repeat, and repeat, and repeat.
I know quite well that some schools of pedagogy or of psychology do not appreciate these activities, since the focus of their researchers is more on competences. However, competences cannot be acquired without skills, and skills cannot be acquired without knowledge. Therefore, we need to impart all classes of knowledge (in the wider sense), and that includes those parts that are acquired by repeated application.
Imparting competences is much more fun, since it is easier to motivate learners by promise of success.
With that in mind, answering your question is at the same time easy and difficult, since learning success depends on so many factors: instructors' ability to motivate and to explain, learners' readiness to: let them motivate; to repeat and to train though it might be tiring; their intellectual ability to understand complex scenarios; their readiness to work on a good knowledge background, since otherwise they have no possibility to compare and to reflect for working on their competences.
This is what makes instructors' work complex, and beautiful.