As we often find, understanding what something is can be aided by thinking about what it is not.
First, cognitive complexity is not difficulty. Memorization of the names of all the US presidents is not cognitively complex, though getting that right is difficult — and notably more difficult that it was when I had to do it in sixth grade. Low cognitive complexity does not assure low difficulty. While higher cognitive complexity tasks often are more difficult, practice can lower difficulty. Furthermore, different people vary in how easy or difficult they find individual tasks. Two people can differ in which of two tasks they find easier, regardless of their relative cognitive complexity.
Second, cognitive complexity is not grade level. The more advanced knowledge, skills and understandings found in later grades are not necessarily higher in cognitive complexity than those found in lower grades. In fact, some of the most advanced forms of knowledge contain large amounts of quite specialized memorized knowledge (e.g., drug dosing information). In fact, most experts have quite a bit of essentially memorized knowledge that is particular to their field — in addition to advanced understandings of complex ideas that they have expertise to apply with greater cognitive complexity and which connect and explain the significance and importance of that lower cognitive complexity stuff.
Third, cognitive complexity is not importance. Low cognitive complexity knowledge can be important or unimportant. Memorizing each of the facts below is low cognitive complexity, but some of them are more important than others.
| Content Area | Low Importance | High Importance |
| ELA | The name of Romeo’s first obsession in Romeo & Juliet | The correct usages of their, there and they're |
| Math | √3 = 1.733 | 7 x 8 = 56 |
| Science | The atomic mass of iron | Carbon dioxide acts as a greenhouse gas |
| Social Studies | Identity of James Polk’s vice-president | Exact wording of the 2nd Amendment to the US Constitution |
Similarly, high cognitive complexity skills can also vary in importance. Now, the square root of 3 (to four significant figures) is 1.732 — and not 1.733, as listed above – and that fact really does matter in some contexts. But memorizing that simply is not important.
Fourth, cognitive complexity is not the number of steps or amount of time a task takes. Memorizing the names of our 46 presidents might take a while to accomplish and certainly has 46 steps. That does not make it particularly cognitively complex. More of the same does not make the task more cognitively complex, even if it makes the task more exhausting or difficult.
Fifth, cognitive complexity is not the context or scope of a task. Low cognitive complexity tasks that are done as part of a larger project are not higher complexity for that scale of that larger task. For example, proof reading a 10 page paper is no more cognitive complex that proofreading a 2 page paper. The larger paper might be more complex and producing it might have been a more cognitively complex task, but the cognitive complexity of proofreading is not changed for the complexity of the larger task — though difficulty, time and number of steps well could have changed.
In fact, tasks of greater cognitive complexity often include or rely on subtasks for lower cognitive complexity. For example, the simple word recognition of sight reading is part of most school work — regardless of the overall cognitive complexity of that school work. But the cognitive complexity of the larger task does not make the subtasks more cognitively complex and the cognitive complexity of the larger tasks is not determined simply by adding up the cognitive complexity of all the subtasks.