Yeah, it just seems like its measuring engagement during the testing.

Would have been better to take measurements at "rest" as well, then compare them.

It'd be a lot easier to believe there's a larger increase in pupil size when concentrating than permenantly.

That being said both my parents had blue eyes, and looking at my DNA I should have blue eyes. But they're green, which can be explained by pupil dilation causing an increase in pigment density. Like how David Bowie has one eye that's permanently dilated so looking at a picture it looks like he has heterochromia when he doesnt.

https://slate.com/culture/2016/01/the-story-behind-david-bowie-s-unusual-eyes.html

Shits interesting, but there's going to need to be a lot of follow up studies to rule out confounding variables.