In my experience both as a learner and as a teacher in a variety of settings from teaching upper-undergrad level science courses to whitewater kayaking, the 'easy' vs 'hard' distinction is quite important on two fronts:<p>1) How easy/hard things are to learn or do the first time, or the first couple of times, or whatever.<p>2) How easy/hard things are to do even when you know what you are doing.<p>Very many tasks are easy or hard w/r/t (2), and are often referred to this way by the teacher. This may be quite different than whether they are easy w/r/t (1). As a student, it's important to use context to determine if an 'easy' task is supposed to be an easy (1), an easy (2) or both. As a teacher, it's critical to be clear about this.<p>If something is an easy (2), it may be a hard (1), because it's abstract, poorly explained, one has improper expectations or training, or it's just plain tricky. I think this is what the article is referring to.<p>In this scenario (easy (2), hard (1)), it's important to describe the task as such: If it keeps being hard for the learner to do, it is a good indication that the approach is wrong, and he or she needs to step back and evaluate things, seek more help, etc. Rolling a kayak is like this. It doesn't require a lot of physical effort to do, just proper technique; so if the kayaker is using a lot of strength and it's still failing, s/he needs to work more on being smooth, keeping his/her head down, and so forth.<p>Contrast this to something that is a hard (2): If a large amount of effort is being expended, this isn't an indication that things are on the wrong track. And it may be that if it seems really easy, then something is actually wrong.