You can't say they're smartest...You can just say they're best at those games...Just like IQ isn't intelligence...It's logic ability...
The "Lumosity" test measures attention, memory, speed, problem-solving, and flexibility. That covers a lot of cognitive ground. It surely isn't a perfect measure of general intelligence, but I think the strong correlation with other measurements is significant.
* they probably did not get an equally good random sample of students at all participating schools
* they didn't test across pre-college and post-college intervals, so they aren't seeing any improvement of student performance over time that might be attributable to the colleges.