Is it really that easy to spot genius? Lord knows which of the students in my classes are little Einsteins... I can barely get them to do homework.
And to tell you the truth, I've got enough on my plate with the kids with this issue and the kids with that issue to really worry about if Johnny Einstein is getting hard enough work.
The 'genius' tag is a hard one to pin down. Traditionally, with regard to verbal intelligence, we've talked about 'giftedness' in terms of students raking in IQ scores over twice the standard deviation of mean; in other words, students scoring over 130 (and more convincingly over 140) on a standard aptitude test. You can also think about it as a student ranking in the 98% percentile.
But, Gardner's research blew a wide hole in that theory of genius. After all, you don't even have to be literate to be a genius musician or painter. Back in the '90s the Sternberg studies demonstrated that students with different strengths respond with different levels of success to different assessments of intelligence. Therefore, a strict adherence to a verbal definition of intelligence is actually going to present a skewed understanding of overall intelligence -- perhaps even more so at those extremes above the second standard deviation.
And therein lies the problem.
Folks often equate giftedness with academic excellence. But the research shows no direct link between the two. In fact, by proportion, in relation to aptitude, there may be more underperforming GT students than underperforming students at any other general aptitude level.
So what does little Einstein look like?
No one knows.
And that's precisely why it's so important to differentiate the instruction and refrain from constant drill, drill, drill. Because something we do know about gifted kids is that by and large mundane tasks act as a discouragement to them. So some of those kids who seem to be struggling in your 'beginner-level' courses might actually be ridiculously gifted kids who are utterly bored and quickly becoming reactionary towards education precisely because it is so unmotivating to them.