Earlier quoted context omitted.
I thought the unique aspect here was comparing techniques against each other. Not that the techniques hadn't been studied. It didn't seem like a great distinction to me, but maybe it eliminates control issues when comparing two studies of different techniques vs comparing two different techniques in one study.
Yeah, I think the head-to-head between techniques is what's novel about the paper. But what confused me is that they got a strong positive off dual n-back in the first place; other studies of that exact technique have regularly come up ambiguous-to-negative.
But IQ isn't working memory, attention, or executive function. And the findings on Dual-N-Back and working memory are less ambiguous and more positive.
Also there have been some more interesting studies done on Dual-N-Back in terms of changing Type 1 dopamine receptor density, as well as volume changes in certain parts of the pre-frontal cortex. So it really does seem like it's doing something even if that doesn't translate into an IQ change.