Kids who played more video games gained more IQ points over two years, even after scientists accounted for their genes and family background. A study of 9,855 American children found gamers gained about 2.5 extra points. Researchers from Karolinska Institutet in Sweden and Vrije Universiteit Amsterdam used data from the ABCD Study, a large US project tracking how kids' brains develop. They tested intelligence at ages 9 to 10 and again two years later, and asked how much time kids spent watching videos, chatting online, and gaming. Smarter kids might pick different screen habits, so the team used DNA to account for each child's inherited tendency toward intelligence, along with family income and background. The study appeared in Scientific Reports in 2022. At the start, kids who watched more videos or chatted online more scored slightly lower, while gaming made no difference. Two years later, kids who gamed more than average had gained about 2.5 extra IQ points. Watching videos also seemed to help, by about 1.8 points, but that result went away when the researchers used parents' education in place of family income. Chatting online had no effect. Which games helped, and how much gaming is too much, the study can't say, and it looked at test scores with no data on school grades. Across nearly 10,000 kids, gaming still came with the biggest gain of any screen activity.

Kids are masters of reward hacking. If your feedback loop for controlling their sugar intake is yelling when you see candy in the bag, they will hide it where you cannot find it. Without explaining that sugar can harm their own compute capability if uncontrolled, they will simply use more compute to not get punished.