The useful answer first
The corrected 2022 JAMA Network Open article found an association between heavy reported gaming and slightly better performance on two laboratory tasks in 9 and 10 year olds. It did not show that gaming caused the difference, that the effect matters in daily life, or that League of Legends data can measure a child’s cognitive ability.
Those distinctions matter because the headline is easy to inflate. The authors themselves described the reaction-time differences as very small and lacking clinical relevance.
What the researchers compared
The study used baseline data from the US Adolescent Brain Cognitive Development project. Its 2,217 participants were 9 or 10 years old.
The researchers created two unusually separated groups:
- children reporting no gaming hours in a typical week;
- children reporting at least 21 gaming hours a week, equivalent to three hours a day.
The final group sizes differed by task. The stop-signal analysis included 1,128 non-gamers and 679 gamers. The n-back analysis included 1,278 non-gamers and 800 gamers.
Participants completed:
- a stop-signal task intended to probe response inhibition;
- an n-back task intended to probe working memory;
- task-based functional MRI, which measured differences in blood oxygen level dependent signals while they performed those tasks.
The analysis adjusted for several demographic, behavioural, and psychiatric variables. Adjustment helps, but it cannot turn a cross-sectional comparison into a randomized experiment.
What the corrected paper found
The gaming group responded faster on parts of both tasks and had higher accuracy-related scores on the n-back task. The paper also reported group differences in task-related fMRI signals across several cortical regions.
The scale is more informative than the direction. The paper called the performance differences very small. For example, adjusted stop-signal reaction times were 287.3 milliseconds in the gaming group and 300.1 milliseconds in the non-gaming group. A statistically detectable difference in a large dataset is not automatically a useful or clinically meaningful effect.
The gaming group also had higher scores for attention problems, depression, and attention-deficit/hyperactivity disorder on the Child Behavior Checklist. That result does not establish that gaming caused those symptoms either. It is another association requiring follow-up.
Four limits that change the interpretation
1. It was a snapshot
Gaming exposure and task performance were measured at the same broad point in time. The study cannot tell whether gaming changed cognition, whether children with different cognitive profiles chose to game more, or whether another factor influenced both.
2. The contrast was extreme
The comparison was not between moderate and slightly heavier play. It compared zero reported weekly gaming with at least 21 hours. The findings should not be treated as a dose recommendation.
3. Game genre was not recorded
The screen-time question did not distinguish strategy games, action games, puzzles, single-player games, or multiplayer games. It therefore cannot support a League-specific conclusion.
4. The article was corrected
JAMA retracted and replaced the original article in April 2023 to correct analysis errors, then added clarifications in August 2023. Use the current corrected article, not an earlier news summary or cached version.
What this means for Saiki
Almost nothing direct.
The study tested children’s response inhibition and working memory in a laboratory. Saiki calculates self-report personality-domain scores and separate experimental gameplay indicators from recent League match statistics. It does not administer the stop-signal or n-back tasks, reproduce this study, or measure cognition.
The paper can support a modest editorial statement: gaming and cognitive-task performance are legitimate research topics. It cannot validate Saiki’s personality mappings, establish an IQ score, or prove that a player’s match history reveals stable psychological traits.
A defensible takeaway
The study is interesting because it uses a large neuroimaging dataset and reports both behavioural and brain-signal differences. The honest conclusion remains narrow: among these children, the two self-reported gaming groups differed slightly on two tasks and on associated fMRI signals. Causal direction, real-world importance, game-specific effects, and transfer to any commercial assessment remain unresolved.