They're testing their systems on epilepsy patients, who have these ECoG systems inserted anyway while they're waiting for surgery (the electrodes record the source of their seizures). The researchers are capturing these patients' movement commands from their brains, and using them to control robotic limbs. Someday such a system could be used by amputees to control their prosthetic limbs.
In between those two states, the other 48 fall in a positive correlation that, while not perfect, is quite undeniable. According to HSI's Edwin Ivanauskas, the correlation is stronger than that between household income and test scores, which have long been considered to be firmly connected to each other. The ACT scores were gathered from ACT.org, which has the official rankings and averages for the 2013 test, and the speed ratings were taken from Internet analytics firm Akamai's latest report.